Post Your Renders - Happy New Year yall

11920222425100

Comments

  • HeadwaxHeadwax Posts: 9,964
    edited February 2015

    Ah no, you'll never get such a wonderful render with one light (well I wouldn't!) I think a minimum of four would be the least, and still not produce such a great result.

    Though ( not on the surface) specifically 3d related I'd highly recommend

    http://www.amazon.com/Color-Light-Guide-Realist-Painter/dp/0740797719
    http://www.amazon.com/Imaginative-Realism-Paint-Doesnt-Exist/dp/0740785508

    Because in our work we are 'painting' what doesn't exist. Hence they are more relevant than they seem.

    It's all about the suspension of disbelief rather than emulating reality. Emulating reality just turns you into a drudge.

    I'm not enamoured of Gurney's style but his insights into the nature of reflected light etc are well worth the price of admission.


    here is his blog site, where he lets more than the occasional gem slip out into the world http://gurneyjourney.blogspot.com.au/

    great work you are doing

    Post edited by Headwax on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    As I have said before, gamma correction is not a "recipe for realism", it is a calibration setting that you only need to apply if your system does not automatically correct for certain nonlinearities in your images. If used when it is not necessary it can adversely affect your renders.

    And as stringtheory's image of the guy's face clearly shows, "realism" is, especially in this case, mostly a function of the hyper-high-resolution head scan and associated textures and bump/displacement maps.

  • HeadwaxHeadwax Posts: 9,964
    edited February 2015

    No need to repeat yourself Joe.

    Post edited by Headwax on
  • stringtheory9stringtheory9 Posts: 411
    edited February 2015

    head wax said:
    Ah no, you'll never get such a wonderful render with one light (well I wouldn't!) I think a minimum of four would be the least, and still not produce such a great result.

    Though ( not on the surface) specifically 3d related I'd highly recommend

    http://www.amazon.com/Color-Light-Guide-Realist-Painter/dp/0740797719
    http://www.amazon.com/Imaginative-Realism-Paint-Doesnt-Exist/dp/0740785508

    Because in our work we are 'painting' what doesn't exist. Hence they are more relevant than they seem.

    It's all about the suspension of disbelief rather than emulating reality. Emulating reality just turns you into a drudge.


    here is his blog site, where he lets more than the occasional gem slip out into the world http://gurneyjourney.blogspot.com.au/

    great work you are doing

    Those book look very much worth a read.


    It's all about the suspension of disbelief rather than emulating reality.

    That is a great quote to keep in mind. I think with the compromises I need to make for the sake of speed, having something not looking fake is way more a priority than having something looking completely realistic.


    Post edited by stringtheory9 on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    head wax said:
    Emulating reality just turns you into a drudge.

    Well, when discussing a medium (3D computer graphics) where most of the practitioners, and certainly many who frequent this forum, are highly interested in "realism", then that kind of sentiment seems a bit misplaced.

    And I suppose some might consider learning a new skill as somehow inhibiting creativity, but personally I don't. I suppose there's a case to be made that the finest painters manage to understand the core of how people are affected by images and the real world around them, and extract those key principles and apply them in magical ways. And since our perceptions are based upon a lifetime of observation of the real world around us, I find it hard to believe there's no merit in understanding how people perceive and react to real world light and texture.

    But anyway...

  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    And from the following discussion about the contents of one of the recommended books, it seems like the author tends to agree with my point:

    "There are lessons on sources of light, light and form, understanding the color wheel, how light reacts with surfaces and other elements, and visual perception. You'll learn interesting things like why the moon looks blue, when happens to light when it travels through green canopy, tips on mixing colors, and a whole lot more."

    Learning about the real world is a good thing.

  • HeadwaxHeadwax Posts: 9,964
    edited December 1969

    head wax said:
    Ah no, you'll never get such a wonderful render with one light (well I wouldn't!) I think a minimum of four would be the least, and still not produce such a great result.

    Though ( not on the surface) specifically 3d related I'd highly recommend

    http://www.amazon.com/Color-Light-Guide-Realist-Painter/dp/0740797719
    http://www.amazon.com/Imaginative-Realism-Paint-Doesnt-Exist/dp/0740785508

    Because in our work we are 'painting' what doesn't exist. Hence they are more relevant than they seem.

    It's all about the suspension of disbelief rather than emulating reality. Emulating reality just turns you into a drudge.


    here is his blog site, where he lets more than the occasional gem slip out into the world http://gurneyjourney.blogspot.com.au/

    great work you are doing

    Those book look very much worth a read.


    It's all about the suspension of disbelief rather than emulating reality.

    That is a great quote to keep in mind. I think with the compromises I need to make for the sake of speed, having something not looking fake is way more a priority than having something looking completely realistic.


    one interesting psych paper I read last year talks about the emotive quality of an image is usually related to suggestion than photorealisim. If you tell the viewer everything they won't engage their brain/emotion as much as if you leave areas where they fill in the blanks. Hence the dark monster you glimpse in the corner of your eye is sometimes more scary than the mouse that is throwing the shadow - courtesy of your emotive input.

  • stringtheory9stringtheory9 Posts: 411
    edited December 1969


    And as stringtheory's image of the guy's face clearly shows, "realism" is, especially in this case, mostly a function of the hyper-high-resolution head scan and associated textures and bump/displacement maps.

    I absolutely agree that the realism in the image of the old man is all due to the high res texture and detail. But it is so easy to screw up those great textures with bad lighting. Essentially most of what we do in 3D graphics is based on lighting some kind of texture along with bump/displacement. When I look at a Pixar movie, even though the characters and scenery cannot be deemed as "real", the lighting and textures still look real.

    I think this is the important take away regardless of the type of render that is being done (ultra realism or cartoon or somewhere in the middle). I myself am not going for ultra real. I am trying to achieve a fantasy art type of look which often has higher saturation and more contrast than what we would experience in real life. But, even with that said, I find the look that I am happiest with is one that looks more realistic which I then tweak to look more fantasy art looking. Otherwise my renders just seem to look fake.

  • MistaraMistara Posts: 38,675
    edited December 1969

    the vending machine stole aiko's change :lol: poor aiko

    Doc2.png
    1689 x 1600 - 1M
    Doc1.png
    1957 x 1600 - 2M
  • Rashad CarterRashad Carter Posts: 1,799
    edited December 1969

    stringtheory, congratulations on being one of the few people to even mention trying the task of matching a real life foto. You can learn a lot from an exercise like that.

    I'm a bit surprised that you're replicating so many low intensity lights.....

    Not sure why you're using so many replicated lights...

    Thanks JoeMamma. I have found that more spots at very low intensities produce much better texture clarity. I don't know the physics behind it but it seems bright lights tend to wash out the detail. I also find that textures that are in the shade of a few bright light sources are unsaturated and dead looking.

    Using lots of low level spots doesn't seem to cause this same effect. I have also found that the more spots used the less hard shadows. The spots in this render use the default hard shadow setting. My goal might be different than many others who are looking to get that perfect still. I have discovered that I am going to have to make a lot of wise compromises if I am going to render a movie in my lifetime.

    I would have expected Joe of all people to already appreciate the logic of this ideal. We have this discussion almost daily in the Bryce forum. After a million exhaustive tests of a thousand different theories, we've come to some clear conclusions. When it comes to faking GI. the more lights the better in most instances. I will explain. This is true regardless of the application in use. Universal truth.

    As most of us well know by now; Point based lights in CG rendering are problematic from the start, mostly because of the hard shadows they cast. Hard shadows are caused by light energy being radiated from an infinitely small point in space. In real life there is no such thing as an infinitely small point that radiates light, so CG gets off on the wrong foot from the start.

    As a basic rule, the smaller a radiant light source may be the harder the shadows it will cast into the world around it. Larger light sources like the sun cast softer shadows. But the hard shadows of individual point lights are just the obvious part of what's wrong with these lights. The less obvious part is that point lights also create "hard illumination" as well as the "hard shadows" we're already seeking to avoid.

    What is "Hard Illumination?" Off hand it is difficult to describe. It generally can be interpreted as a cheapness, a fakeness to the overall lighting. It tends to be a lighting scheme that lacks in subtlety. Hard lighting is exaggerated lighting. How does the exaggeration tend to occur?

    Answer: Because really small sized light sources not only cast hard (sharp) edged shadows, they also cast hard edged diffuse and specular highlights. They also produce harsher looking bump response. More in a moment.

    Keep in mind that a specular highlight is basically a blurred reflection of the light source itself, not the environment. So a large light source creates a wider specular with a softer edge gradient than a physically smaller light source of the same intensity would produce.

    Soft Shadows, when enabled, basically tell the render engine to redistribute the light being emanated from this single point to instead emanate from a "general area" around the center of the original point. The size of that area is determined by the user, larger areas are softer shadows. The total illumination of a single point is simply divided evenly among thousands of (virtual) points who's combined intensity equals that of the original point source. Because the rays are cast from an area instead of from a single origin their randomly scattered rays will arrive on the target mesh at differing angles producing what will appear to be a softened gradient shadow. In theory, enabling Soft Shadows should correct the basic flaw of the point light source. But not so fast.

    Here is a surprising fact. Even with Soft Shadows enabled, most point lights in CG (Including Carrara) still behave as tiny points when calculating specular highlights and diffuse highlights. By enlarging the "size" of your point light to produce soft shadows, you have ALSO enlarged the area that casts specular into the scene, which should result in a softer looking specular highlight as well. In theory, a soft shadow casting light source should produce a wider specular highlight, which we know is not the case when rendering in Carrara or in Bryce for that matter. Specular has to be adjusted separately from shadow softness in the shader and light settings regardless of the degree of shadow softness. But in real life, shadow softness and specular output are both affected by the physical size of a light source. Not so in Carrara or in most other biased engines.

    Since the rendering equation factors both diffuse and specular reflections, point based lights often end up creating exaggerated looking specular highlights even when soft shadows are enabled. This makes sense, because all of the specular energy is still concentrated into a single point, it isn't truly being dispersed over an area the way the soft shadow setting would want you to believe. So while the shadows light look nice and soft, the specular is still hard and therefore wrong.

    When faking GI, there are two considerations, Key Light and Indirect Light. It's obvious to most people that indirect light should appear to come from a general area, not a mere point. But indirect light should be both diffuse and specular in nature. Employing lots of dim light sources around the room is a good way to fake indirect lighting both in terms of diffuse and specular. But there is a good chance that you also want to avoid using individual point lights for key lighting as well, as using a light dome placed in the distance will also produce softened shadows in the final render output. Mesh lights are also a great solution since they avoid points all together.

    Having the rays casting from an area instead of a single point also creates better looking bump response. When all the light comes from a single infinitely tiny point there is no extra light to fill in some of those overly dark bumps in areas that face away from the point light source. But when casting rays from an area, at least a few of those rays are likely to end up penetrating those crevices created by the bump making the bump seem less extreme and harsh/fake.

    Using multiple point lights to create the impression of continuous illumination coming from a general area is what faking GI is really all about.

    The rule of thumb that I have come up with is that the full screen scene (1400 x 700) without characters has to render in under a minute at 2 pixel accuracy or I have to adjust something.

    When animating one should definitely count the minutes. Often quality will suffer for the sake of speed, but the real issue is the final balance of trade offs. So far so good based on the example you've uploaded.

    Having a real photo to use as a lighting guide is very useful but feedback from experienced users is the best. I'll be taking another swing at those surfaces :-)

    To my eye you could afford more light within the room than you have now. You've matched well enough the light coming in from the outside window. What I am missing is the light that has bounced around and returned to the wall where the windows are placed. As bright as those windows are, we can still see clearly the yellow painted wall these window sills are are placed within.

    It looks to me like you are "Spot Light Mapping" the surfaces of some of the items to appear to reflect some light back toward the center of the room. Truthfully, this approach can produce very nice results but it usually requires that you carefully map every single surface in the scene, which is very tedious.

    And that is how we got the incredible 3D Fill Light in Bryce 7.It is a BRILLIANT light source. When David Brinnen approached the fake GI study he had seen my generalized success using spotlight mapping, but he felt there HAD to be an easier way. He soon realized that instead of mapping each surface in the scene with spotlights, he could produce a better looking indoor GI by creating a network of floating radials within the volume of the room itself, kind of like air molecules randomly floating around. We asked the programmers to make this hand made light trick into an official lighting tool in Bryce 7 and Daz kindly did so.

    What this network of floating radials did that looked so good was that it got both light and shadow rays flying around in almost every direction, creating a nearly bias free ambient occlusion. It did a great job of carving out the geometric details without making the image appear flat and 2d the way scene ambience and glow channels would have.

    Below are a few links. First are a few links to the Fake GI studies we conducted all those years ago, where the ideals discussed above were discovered.

    This is the original Carrara 6 Cornell Room reference scene rendered with Full GI
    http://www.bryce5.com/details.php?image_id=3135&mode=search

    This was my attempt at recreating those Carrara 6 full GI results in Bryce using Spot Light Mapping
    http://www.bryce5.com/details.php?image_id=3131&mode=search

    Here is wireframe view of the spotlights I used to produce the appearance of the color bleed.
    http://www.bryce5.com/details.php?image_id=3132&mode=search

    Needless to say, the more dim lights I use in the simulation the smoother the resulting illumination.

    Lastly is a link to a recent render I did using the 3D Fill Light, which as I explained above, is an elegant solution available in Bryce 7 only to aid users in producing plausible fake GI for interiors.

    http://www.bryce5.com/details.php?image_id=5259&mode=search

    Fun fun

  • stringtheory9stringtheory9 Posts: 411
    edited December 1969

    Rashad,

    Thank you for a very informative post. The technical explanation of the multiple source vs. point lighting is great and makes a lot of sense. And thank you for the clear and helpful feedback on my scene lighting.

    The 3D fill lighting in your room render look amazing. What is the impact on rendering time?

    I have been wanting to test out a technique I've been thinking of (or maybe it's already being done). The Baker plugin lets you bake all shading domains into one texture map. You can also bake the rendered lighting into the texture. My thinking is that an indirect GI light render on a white surface would produce a gradient based spot light map. This can be baked into a single texture. The model could then be used as a surface replicator source and spot lights could then be replicated using the baked light map. Essentially a quickly way to emulate level of light emanating from dark and light areas of a baked GI surface. I have no idea if this is something that in practice will work; I guess I should give it a try.

  • scottidog2scottidog2 Posts: 319
    edited December 1969

    Rashad, I think your understanding of CGI lighting is quite deep. Thank You for bringing this awareness to our attention.

  • TangoAlphaTangoAlpha Posts: 4,584
    edited December 1969

    Here's another little track render. I'm sure you're all getting quite bored by now!

    Gonna play some more with the fake GI dome - more lights at lower intensity, as per the discussion here. Be interesting to see what that does (and how long it takes - with full GI, this render took about 4 ½ hours at AA-OA-SA settings of Good-0.5-1, gamma 1.8)

    EastTrack.jpg
    1300 x 1000 - 1M
  • MarkIsSleepyMarkIsSleepy Posts: 1,496
    edited February 2015

    the vending machine stole aiko's change :lol: poor aiko

    In that outfit she'll probably have no trouble borrowing some change from someone. :) Great expression on her face Misty.

    Here's another little track render. I'm sure you're all getting quite bored by now!

    Gonna play some more with the fake GI dome - more lights at lower intensity, as per the discussion here. Be interesting to see what that does (and how long it takes - with full GI, this render took about 4 ½ hours at AA-OA-SA settings of Good-0.5-1, gamma 1.8)

    Tim, I love every render of this set so much - it makes me want to go outside for a hike. Too bad it's 5 degrees F right now here. :(


    About the discussion about realism and lighting - my totally amateur two cents is that we should consider the final audience when balancing "realistic" v. "good enough." I have several recent renders I like on my desktop at work; none of them are perfect, in fact I think any one of us would find numerous flaws in them. But I get people asking all the time "where were those photos taken?" One image is a WIP mountain scene that I posted upthread - it has A LOT of issues still, but a woman who grew up in a mountainous region of Poland and saw real scenes just like that every day for the first 30 years of her life thought it was "amazing" and looked just like a real spot she knew.

    So if you are stressing out over the realism of the lighting and textures of your images, try showing them to someone who knows nothing about 3D or even about art - you might be surprised by how many of the issues that are bothering you are not even noticed by someone who doesn't look at renders every day. :)

    It's not necessary to perfectly emulate a photo - in my experience the human brain will fill in a lot of details based on their own experience and a lot of that extra time spent getting the tiny details perfect is wasted unless your intended audience is a group of artists.

    Post edited by MarkIsSleepy on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    head wax said:
    No need to repeat yourself Joe.

    Well, considering the refrain "Did you try use gamma of 2.2 to improve your render" is repeated here almost on a daily basis, I think a couple times a year mentioning a different perspective can't hurt can it? Or maybe it can... :) :)

  • VarselVarsel Posts: 574
    edited December 1969

    My latest Desktop Wallpaper.
    Just a quicky made for my girl's New Year Celebration.

    The text in the sky is Vietnamese and it means :

    May myriad things go according to your will

    (or that is what Wikipedia tells me - and she hasn't protested )

    Doc5red.jpg
    1920 x 1080 - 545K
  • DADA_universeDADA_universe Posts: 336
    edited December 1969

    stringtheory, congratulations on being one of the few people to even mention trying the task of matching a real life foto. You can learn a lot from an exercise like that.

    I'm a bit surprised that you're replicating so many low intensity lights.....

    Not sure why you're using so many replicated lights...

    Thanks JoeMamma. I have found that more spots at very low intensities produce much better texture clarity. I don't know the physics behind it but it seems bright lights tend to wash out the detail. I also find that textures that are in the shade of a few bright light sources are unsaturated and dead looking.

    Using lots of low level spots doesn't seem to cause this same effect. I have also found that the more spots used the less hard shadows. The spots in this render use the default hard shadow setting. My goal might be different than many others who are looking to get that perfect still. I have discovered that I am going to have to make a lot of wise compromises if I am going to render a movie in my lifetime.

    I would have expected Joe of all people to already appreciate the logic of this ideal. We have this discussion almost daily in the Bryce forum. After a million exhaustive tests of a thousand different theories, we've come to some clear conclusions. When it comes to faking GI. the more lights the better in most instances. I will explain. This is true regardless of the application in use. Universal truth.

    As most of us well know by now; Point based lights in CG rendering are problematic from the start, mostly because of the hard shadows they cast. Hard shadows are caused by light energy being radiated from an infinitely small point in space. In real life there is no such thing as an infinitely small point that radiates light, so CG gets off on the wrong foot from the start.

    As a basic rule, the smaller a radiant light source may be the harder the shadows it will cast into the world around it. Larger light sources like the sun cast softer shadows. But the hard shadows of individual point lights are just the obvious part of what's wrong with these lights. The less obvious part is that point lights also create "hard illumination" as well as the "hard shadows" we're already seeking to avoid.

    What is "Hard Illumination?" Off hand it is difficult to describe. It generally can be interpreted as a cheapness, a fakeness to the overall lighting. It tends to be a lighting scheme that lacks in subtlety. Hard lighting is exaggerated lighting. How does the exaggeration tend to occur?

    Answer: Because really small sized light sources not only cast hard (sharp) edged shadows, they also cast hard edged diffuse and specular highlights. They also produce harsher looking bump response. More in a moment.

    Keep in mind that a specular highlight is basically a blurred reflection of the light source itself, not the environment. So a large light source creates a wider specular with a softer edge gradient than a physically smaller light source of the same intensity would produce.

    Soft Shadows, when enabled, basically tell the render engine to redistribute the light being emanated from this single point to instead emanate from a "general area" around the center of the original point. The size of that area is determined by the user, larger areas are softer shadows. The total illumination of a single point is simply divided evenly among thousands of (virtual) points who's combined intensity equals that of the original point source. Because the rays are cast from an area instead of from a single origin their randomly scattered rays will arrive on the target mesh at differing angles producing what will appear to be a softened gradient shadow. In theory, enabling Soft Shadows should correct the basic flaw of the point light source. But not so fast.

    Here is a surprising fact. Even with Soft Shadows enabled, most point lights in CG (Including Carrara) still behave as tiny points when calculating specular highlights and diffuse highlights. By enlarging the "size" of your point light to produce soft shadows, you have ALSO enlarged the area that casts specular into the scene, which should result in a softer looking specular highlight as well. In theory, a soft shadow casting light source should produce a wider specular highlight, which we know is not the case when rendering in Carrara or in Bryce for that matter. Specular has to be adjusted separately from shadow softness in the shader and light settings regardless of the degree of shadow softness. But in real life, shadow softness and specular output are both affected by the physical size of a light source. Not so in Carrara or in most other biased engines.

    Since the rendering equation factors both diffuse and specular reflections, point based lights often end up creating exaggerated looking specular highlights even when soft shadows are enabled. This makes sense, because all of the specular energy is still concentrated into a single point, it isn't truly being dispersed over an area the way the soft shadow setting would want you to believe. So while the shadows light look nice and soft, the specular is still hard and therefore wrong.

    When faking GI, there are two considerations, Key Light and Indirect Light. It's obvious to most people that indirect light should appear to come from a general area, not a mere point. But indirect light should be both diffuse and specular in nature. Employing lots of dim light sources around the room is a good way to fake indirect lighting both in terms of diffuse and specular. But there is a good chance that you also want to avoid using individual point lights for key lighting as well, as using a light dome placed in the distance will also produce softened shadows in the final render output. Mesh lights are also a great solution since they avoid points all together.

    Having the rays casting from an area instead of a single point also creates better looking bump response. When all the light comes from a single infinitely tiny point there is no extra light to fill in some of those overly dark bumps in areas that face away from the point light source. But when casting rays from an area, at least a few of those rays are likely to end up penetrating those crevices created by the bump making the bump seem less extreme and harsh/fake.

    Using multiple point lights to create the impression of continuous illumination coming from a general area is what faking GI is really all about.

    The rule of thumb that I have come up with is that the full screen scene (1400 x 700) without characters has to render in under a minute at 2 pixel accuracy or I have to adjust something.

    When animating one should definitely count the minutes. Often quality will suffer for the sake of speed, but the real issue is the final balance of trade offs. So far so good based on the example you've uploaded.

    Having a real photo to use as a lighting guide is very useful but feedback from experienced users is the best. I'll be taking another swing at those surfaces :-)

    To my eye you could afford more light within the room than you have now. You've matched well enough the light coming in from the outside window. What I am missing is the light that has bounced around and returned to the wall where the windows are placed. As bright as those windows are, we can still see clearly the yellow painted wall these window sills are are placed within.

    It looks to me like you are "Spot Light Mapping" the surfaces of some of the items to appear to reflect some light back toward the center of the room. Truthfully, this approach can produce very nice results but it usually requires that you carefully map every single surface in the scene, which is very tedious.

    And that is how we got the incredible 3D Fill Light in Bryce 7.It is a BRILLIANT light source. When David Brinnen approached the fake GI study he had seen my generalized success using spotlight mapping, but he felt there HAD to be an easier way. He soon realized that instead of mapping each surface in the scene with spotlights, he could produce a better looking indoor GI by creating a network of floating radials within the volume of the room itself, kind of like air molecules randomly floating around. We asked the programmers to make this hand made light trick into an official lighting tool in Bryce 7 and Daz kindly did so.

    What this network of floating radials did that looked so good was that it got both light and shadow rays flying around in almost every direction, creating a nearly bias free ambient occlusion. It did a great job of carving out the geometric details without making the image appear flat and 2d the way scene ambience and glow channels would have.

    Below are a few links. First are a few links to the Fake GI studies we conducted all those years ago, where the ideals discussed above were discovered.

    This is the original Carrara 6 Cornell Room reference scene rendered with Full GI
    http://www.bryce5.com/details.php?image_id=3135&mode=search

    This was my attempt at recreating those Carrara 6 full GI results in Bryce using Spot Light Mapping
    http://www.bryce5.com/details.php?image_id=3131&mode=search

    Here is wireframe view of the spotlights I used to produce the appearance of the color bleed.
    http://www.bryce5.com/details.php?image_id=3132&mode=search

    Needless to say, the more dim lights I use in the simulation the smoother the resulting illumination.

    Lastly is a link to a recent render I did using the 3D Fill Light, which as I explained above, is an elegant solution available in Bryce 7 only to aid users in producing plausible fake GI for interiors.

    http://www.bryce5.com/details.php?image_id=5259&mode=search

    Fun fun

    Thank you for this rather 'illuminating' explanation Rashad, I was already sufficiently intrigued by StringTheory's approach (and thanks to him for keeping this on the front burner) to try it for my entry in this month's Carrara challenge, I found it to have a lot of promise, now I understand how and why it works even more, very interesting logic behind it too, I'm amazed at how fast it renders given that with two or three lights in your scene, there's little to calculate, yet the replicator delivers the power of a thousand lights for the same effort! An invaluable lighting technique for animations and stills too for that matter....

  • DADA_universeDADA_universe Posts: 336
    edited December 1969

    Varsel said:
    My latest Desktop Wallpaper.
    Just a quicky made for my girl's New Year Celebration.

    The text in the sky is Vietnamese and it means :

    May myriad things go according to your will

    (or that is what Wikipedia tells me - and she hasn't protested )

    Nice

  • DiomedeDiomede Posts: 15,125
    edited December 1969


    Below are a few links. First are a few links to the Fake GI studies we conducted all those years ago, where the ideals discussed above were discovered.

    This is the original Carrara 6 Cornell Room reference scene rendered with Full GI
    http://www.bryce5.com/details.php?image_id=3135&mode=search

    This was my attempt at recreating those Carrara 6 full GI results in Bryce using Spot Light Mapping
    http://www.bryce5.com/details.php?image_id=3131&mode=search

    Here is wireframe view of the spotlights I used to produce the appearance of the color bleed.
    http://www.bryce5.com/details.php?image_id=3132&mode=search

    Needless to say, the more dim lights I use in the simulation the smoother the resulting illumination.

    Lastly is a link to a recent render I did using the 3D Fill Light, which as I explained above, is an elegant solution available in Bryce 7 only to aid users in producing plausible fake GI for interiors.

    http://www.bryce5.com/details.php?image_id=5259&mode=search

    Fun fun

    Thank you for this rather 'illuminating' explanation Rashad, I was already sufficiently intrigued by StringTheory's approach (and thanks to him for keeping this on the front burner) to try it for my entry in this month's Carrara challenge, I found it to have a lot of promise, now I understand how and why it works even more, very interesting logic behind it too, I'm amazed at how fast it renders given that with two or three lights in your scene, there's little to calculate, yet the replicator delivers the power of a thousand lights for the same effort! An invaluable lighting technique for animations and stills too for that matter....

    Yes, thanks to all concerned for such an "illuminating" discussion. :cheese:

  • evilproducerevilproducer Posts: 9,050
    edited February 2015

    Tim_A said:
    Here's another little track render. I'm sure you're all getting quite bored by now!

    Gonna play some more with the fake GI dome - more lights at lower intensity, as per the discussion here. Be interesting to see what that does (and how long it takes - with full GI, this render took about 4 ½ hours at AA-OA-SA settings of Good-0.5-1, gamma 1.8)

    I think that looks great Tim. Makes me want to take a stroll down it as well, but like MDO2010 it is very cold here, although I think I have him beat as mine is in the negative and not positive. ;-)

    -2ºF (approximately -19ºC) here in north central Wisconsin. I can't wait for spring.

    Picture_1.png
    254 x 153 - 46K
    Post edited by evilproducer on
  • TangoAlphaTangoAlpha Posts: 4,584
    edited February 2015

    Okay here's the results of a back-to-back GI/Fake GI render, using the lots of very dim (1%) lights suggestion from higher up the thread. Gamma for both images was 2.2.

    The shadows in the GI render are almost totally black. bear in mind that these are big trees - 60ft typically, so not a whole lot of light will get through. I don't think you'll get a lot of detail in the shadows without burning out the bright areas (much like real life I guess). I might try a 'bright' render and see what happens.

    The fake GI setup had about 60 lights on a hemisphere at 1%, plus a green uplight set to ignore the ground. Much more detail in the shadows, but it's all kinda muddy andy lacking in contrast.

    In both images, the Gia figure is lit by a separate distant light set to 'Only Gia 6' (Ringo Monfort shader on Gia, but I need to tweak it to look less like fake tan and add a sweaty sheen. Guess I need to hit the skin shader threads!)

    The most surprising thing though is the render times. The GI render took 55 minutes - much less than other renders (4 ½ hours typical). I guess that's because it's a tighter shot, looking out of the scene and so there are only a handful of trees visible. The fake GI shot (2 hours typical on the other renders using 20 lights @ 7%) took a whopping 6 HOURS!!

    I don't think I'm in a hurry to try that again!

    Edit: Cranked the sunlight up to 800% for the last shot. 90 minute render, but looks a lot better I think.

    Stile-GI3.jpg
    1300 x 1000 - 1M
    Stile-Fake.jpg
    1300 x 1000 - 1M
    Stile-GI2.jpg
    1300 x 1000 - 1M
    Post edited by TangoAlpha on
  • stringtheory9stringtheory9 Posts: 411
    edited December 1969

    Tim_A said:
    Here's another little track render. I'm sure you're all getting quite bored by now!

    Gonna play some more with the fake GI dome - more lights at lower intensity, as per the discussion here. Be interesting to see what that does (and how long it takes - with full GI, this render took about 4 ½ hours at AA-OA-SA settings of Good-0.5-1, gamma 1.8)

    I think that looks great Tim. Makes me want to take a stroll down it as well, but like MDO2010 it is very cold here, although I think I have him beat as mine is in the negative and not positive. ;-)

    -2ºF (approximately -19ºC) here in north central Wisconsin. I can't wait for spring.

    It's going to be getting pretty freakin cold here on Monday night too!

    image.jpg
    640 x 1136 - 107K
  • TangoAlphaTangoAlpha Posts: 4,584
    edited February 2015

    43F? That was our high today - barmy warm!

    Post edited by TangoAlpha on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited February 2015


    Hard shadows are caused by light energy being radiated from an infinitely small point in space.

    As a basic rule, the smaller a radiant light source may be the harder the shadows it will cast into the world around it. Larger light sources like the sun cast softer shadows. But the hard shadows of individual point lights are just the obvious part of what's wrong with these lights. The less obvious part is that point lights also create "hard illumination" as well as the "hard shadows" we're already seeking to avoid.

    Rashad,
    That's an interesting treatise on lighting and shadows. But at the risk of inducing glassy-eyed disinterest and even, I imagine, some anger and dismissal from some forum members, I think you clearly have some basic misunderstandings on the topic.

    First, your belief that the size of the light source determines the softness/hardness of the shadows it will generate is, well, factually incorrect. And to say that the sun casts softer shadows since it is a large light source is, fairly obviously, just not true. I'm kind of surprised that you haven't seen extremely hard shadows generated by the sun on a clear day. Or conversely, soft shadows generated by a single "point source" light bulb behind a frosted glass.

    Honestly, I've been trying to figure out where to start in this discussion.

    But let me just clarify your basic premise...it is not the size of the light source which determines the hardness or softness of the shadows it casts. It is the “diffuseness” of the light source, combined with the characteristics of the surfaces surrounding the objects in your scene.

    What does that mean? Well, a diffuse light source is one which casts light rays in many different directions. For example, sunlight is, when it reaches the earth, all parallel rays of light in the same direction. Which is why sunlight alone, on a clear day with no diffuse light bouncing around the sky, casts extremely hard shadows. It is unidirectional light rays that are “collimated”. Basically a big word for parallel and uniform, not coming from all different directions. And since “collimated” light rays don't bend around stuff, they just keep going in the same direction, they generate harsh shadows.

    However, on a cloudy day, the light hitting the earth is not direct, unidirectional, parallel rays, it is light that bounces around inside the clouds. And that “diffuse” light causes soft shadows. Why? Because the light comes from many different directions, and “wraps around” the lighted object. And that light also bounces off surrounding surfaces, and makes the light even more diffuse, as well as inheriting the color of the surface it bounces off.

    Same thing occurs when a photographer uses a “soft box” or a “light wall”. You take a bunch of lights and apply a uniform, diffuse material in front of it to convert the “hard” lights into a diffuse light that bounces all around the object being photographed and makes nice, soft shadows. It's the diffuseness, the multi-directionality of the light rays, that causes the soft shadow effect.

    Keeping all of that in mind, in real life, it is very difficult to build a large light source that is NOT diffuse. The sun is a huge, non-diffuse light source. But typically all of our man-made light sources are point sources, made by heating elements that emit light, or LED's that emit diffuse light, etc. So if we need a diffuse light source, we need to convert those standard bulbs to diffuse light sources for photography, etc., when we need diffuse, soft shadows.

    Now, a single incandescent light bulb inside a clear glass is a point source of light, and it generates hard shadows. But the exact same light inside a frosted, diffuse glass will generate much softer shadows. That's why we buy “soft white” light bulbs. We don't like harsh shadows in our homes.

    Because really small sized light sources not only cast hard (sharp) edged shadows, they also cast hard edged diffuse and specular highlights. They also produce harsher looking bump response. More in a moment.

    Keep in mind that a specular highlight is basically a blurred reflection of the light source itself, not the environment. So a large light source creates a wider specular with a softer edge gradient than a physically smaller light source of the same intensity would produce.

    Wow...okay, well, I think there's another basic misunderstanding here. “Highlights”, specular or otherwise, are, in the real world, nothing more than the degree to which an object's surface reflects its environment. Period. That can include how it reflects light sources (like the sun or a light bulb), but it can also include any light reflected off surrounding objects. But the quality of the “highlight” is a function of the surface characteristics. A more uniform, reflective surface gives a “harder” and clearer reflection (think a shiny piece of highly reflective brass), while bumpier and more diffuse surface will give a softer reflection (or highlight, or whatever you want to call it). But keep in mind, in the real world there is no such thing as specular highlight or anything like that. It is all just reflections. Because, as I've said before, everything you “see” is nothing more than light bouncing off a surface somewhere. It's all reflections.

    In theory, a soft shadow casting light source should produce a wider specular highlight,

    Again, I think you're mistaken. Reflections are solely a function of the reflecting surface. I could be photographing a shiny chrome object with a soft box, and the “specular highlight” (aka, reflection) will be VERY clear, like a mirror, even thought the light source is very diffuse and generates soft shadows.

    When faking GI, there are two considerations, Key Light and Indirect Light. Using multiple point lights to create the impression of continuous illumination coming from a general area is what faking GI is really all about.

    Now, all of that being said, what causes soft shadows is lots of diffuse bounce light, or non-directional light coming from multiple sources OR surface reflections. Diffuse light that surrounds the object you are lighting. The reason why sunlight can cast soft shadows, even though it is highly unidirectional and collimated, is because it bounces off all the diffuse, bumpy surfaces around you, including the clouds and the atmosphere. And it is converted into diffuse light. And if you have a bright point source light in a highly reflective environment, with lots of diffuse surfaces, the bounce light will generate softer shadows.

    Think of it this way: let's say we're in a spaceship that is relatively close to the sun. And the sun is a HUGE light source, but its light rays are very unidirectional. So even we're standing 100 miles from the surface of the sun, and it is a HUGE light source, the shadows it generates are extremely harsh. SOLELY because it is not a diffuse light source.

    So the challenge in faking GI is to generate what appears to be diffuse light in your scene. And depending on whether you want and can afford a 100% solution, or a 90% solution or can settle for an 80% solution, there are a variety of methods to achieve your goal.

    Personally, I'm of the belief that those with a basic understanding of lighting and surfaces can obtain an 80 or 90% solution with only a handful of lights in their scenes. Especially if your scene is outdoors, or is illuminated by a single main light source, like the sun. When you move indoors, where most of your illumination is by diffuse bounce light, and non-linear man-made lights of varying colors and intensities, it becomes more difficult.

    Here's an example, what I consider an 80-90% solution which rendered very fast, and used only 5 spot lights and soft shadows. Certainly not for everyone, but at least it is an example of how you can get reasonable results with only a few lights and a decent understanding of how light and surfaces respond.

    Five_Lights.jpg
    808 x 644 - 82K
    Post edited by JoeMamma2000 on
  • stringtheory9stringtheory9 Posts: 411
    edited December 1969

    Tim_A said:
    43F? That was our high today - barmy warm!

    Us Southern Californians are big babies. :cheese:

  • Bunyip02Bunyip02 Posts: 8,341
    edited December 1969

    Tim_A said:
    Okay here's the results of a back-to-back GI/Fake GI render, using the lots of very dim (1%) lights suggestion from higher up the thread. Gamma for both images was 2.2.

    The shadows in the GI render are almost totally black. bear in mind that these are big trees - 60ft typically, so not a whole lot of light will get through. I don't think you'll get a lot of detail in the shadows without burning out the bright areas (much like real life I guess). I might try a 'bright' render and see what happens.

    The fake GI setup had about 60 lights on a hemisphere at 1%, plus a green uplight set to ignore the ground. Much more detail in the shadows, but it's all kinda muddy andy lacking in contrast.

    In both images, the Gia figure is lit by a separate distant light set to 'Only Gia 6' (Ringo Monfort shader on Gia, but I need to tweak it to look less like fake tan and add a sweaty sheen. Guess I need to hit the skin shader threads!)

    The most surprising thing though is the render times. The GI render took 55 minutes - much less than other renders (4 ½ hours typical). I guess that's because it's a tighter shot, looking out of the scene and so there are only a handful of trees visible. The fake GI shot (2 hours typical on the other renders using 20 lights @ 7%) took a whopping 6 HOURS!!

    I don't think I'm in a hurry to try that again!

    Edit: Cranked the sunlight up to 800% for the last shot. 90 minute render, but looks a lot better I think.

    Hello Tim

    I definitely liked the 3rd shot as well, less render time is even better.
    I'm still getting my head around how to best balance scenes with lights with render times.
    Guess that will happen with the more I use Carrara, but it's nice knowing other peoples experiences !!!!!!!

    Regards, Bunyip

  • DartanbeckDartanbeck Posts: 21,326
    edited February 2015

    Tim_A said:
    The shadows in the GI render are almost totally black. bear in mind that these are big trees - 60ft typically, so not a whole lot of light will get through.
    It adds a quite a bit to render time, but adding a bit of translucency to the leaves will allow light to pass through the leaves just enough to give a super-natural amount of detail using realistic lighting - without a cheat light from underneath. Adding Indirect Lighting can further add a LOT of realism but, of course, with a major hit on render times.

    In Howie Farkes scenes, set up the way he advises (his defaults) have this translucency added along with an artificial GI which works very well with his scenes. They are an excellent study course in natural realism rendering in wooded areas. In my EnvironKits, I weigh more heavily on the scene being a background for something much more important - something which the user adds to the scene. They still work using the scenes as the focus, but were designed to render much faster - allowing for animated outdoors scenes. So I've used a three (or more) light artificial indirect light rig in order to eliminate the need for translucency in the leaves - something that is a MUST, or must be cheated in order to get good shadows/light passage through dense forest - otherwise... yeah... black shadows prevail.

    With a cheat light system, even if it's only one light, it's important to find a happy medium to get it right, It's easy to add too much, and just as easy to have too little. The thing is, this happy medium will often be different for different people with different situations - the reason why I include separate presets for different conditions - helps get a start on the lighting. Howie also does some of this. His more closely resemble yours... highly details landscapes of immense clarity and realism.

    I think that you are doing a magnificent job with this piece! I love seeing your progress - and am always looking forward to seeing the next images! Bravo Tim_A!!! Bravo!!!

    EDIT:
    After looking at that last image with the high intensity light, I really love that one, and would love to see what just a tiny bit of leaf translucency would bring to the table. If you've never tried leaf translucency, what I do is set the translucency channel to "color" and set that color chip to what I imagine the leaf would do to light - what color would glow on the underside of the leaf. After that, to reduce the effect a lot (which is often very much necessary) drag the color almost all the way to the black corner of the triangle, more toward the color end than the gray scale side - if you get what I mean.

    Post edited by Dartanbeck on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    By the way, I hesitate to recommend non-Carrara-specific reading materials here, but in case there's anyone who wants to go a little deeper into understanding lighting and surfaces and how we perceive things, there's a very good book entitled "Visual Perception from a Computer Graphics Perspective"

    I'm a bit biased cuz one of the authors is an acquaintance of mine, and I haven't read the entire book (just skimmed it...), but I was pretty impressed by what I read. So if you want a deeper understanding of lighting and shadows and surfaces and how we perceive them, and how that affects our expectations when viewing CG images, you might want to take a look at it.

    On the other hand, they tend to agree with much of what I've been saying here over the years, so some might want to look elsewhere for reading materials :) :) :)

  • evilproducerevilproducer Posts: 9,050
    edited February 2015

    A "cheat" light from underneath isn't supposed to mimic leaf translucency, it is meant to simulate the light from the sun or sky, reflected off the ground back up towards the trees or structures. Basically it is supposed to mimic Indirect Light. I think Tim's issue with it looking flat is that it may be too bright or the shadows may not be as close to 100% as they could be. Or maybe it is the Gamma settings.

    The Skylight, if it is faster than the simulated GI rig, can still benefit from the ground light, because the Skylight doesn't reflect like full IL, so the terrain itself will block the 360º "atmospheric" light that the Skylight provides, only letting the light in from the top and sides.

    You are right of course that adding translucency to the leaves will add to the realism of the scene by allowing more filtered light through the trees illuminating the ground (but again, not reflecting upwards). As you mentioned, it will slow the render down considerably.

    There is also the ability to add a very, slight glow to the leaves of the trees to simulate the effect of translucency, but it won't allow the filtered light and could also compound the "flatness" of the lighting...

    Which brings me to a general observation of the whole Gamma thing and lighting "cheats." The method to get the best results from the Gamma settings is to not use the cheats as they are not part of a truly linear workflow, as outlined by Jeremy Birn in his Digital Lighting and Rendering book. Even when Phil initially brought up the concept of the 2.2 Gamma setting, he mentioned (if I recall correctly) that it was best used with GI, which is what most of the "cheats" are meant to simulate. So, if you're using lighting tricks to simulate GI, then it may be best to dial back the Gamma a bit.

    As to what constitutes a cheat that may not work well with Gamma, I would have to say that less than 100% shadow intensity could cause issues with it. Glow channels in the shader could also cause some problems. There are more I'm sure, but I'm getting tired and should probably go to bed.

    Post edited by evilproducer on
  • HeadwaxHeadwax Posts: 9,964
    edited December 1969

    Hi Tim

    Thanks for posting those renders, interesting the difference.
    Just thought you would like to see them combined with hdr program - all the details are present just a matter of getting them in one image!

This discussion has been closed.