Softer shadows in Carrara
sheila.moore
Posts: 21
Is there a way to soften the shadows other than check the soft shadows tab? The shadows a re still abit sharp. In DS you can dial in a raytraced number but I dont see anything like that in Carrara. Thanks
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2024 Daz Productions Inc. All Rights Reserved.
Comments
The soft shadow is used by lights with no size to mimick lights with size.
Other ways of doing it are :
After working with unbiased renderer (octane, lux, mitsuba), I must say I prefer the latter.
But I believe that's not the answer to your question.
You can adjust the softness using the "light radius" setting (wich represent the size of the light). You have to take into account the distance from the light to the object casting the shadow.
For instance, for a hazy sun (very far) , a size of 50 is a good start.
I am a new user. Can you tell me what a light with no size is?
No, there is no way to soften them better.
Carrara is using fixed number of samples with tree settings: fast, good and best.
Negative aspect of this is if radius of your light is big enough banding will occur
To avoid the banding effect, you can duplicate the light, halve the power and set different radius (for instance, 25 and 50 for a distant light). You can also use a warmer colour for the light with the smallest radius light.
A bulb, a spot or a distant light are just coordinates, precise to the nth decimal. They could be described as infintaly small, occupuying no space. To see is a point is lit or shadowed, a test is made to those coordinates. That makes for very sharp shadows (either seen or not seen).
With a shape light or a mesh lit with anything glows, the light has an actual geometry and occupies a volume in space. So, the test to see if a point is lit or shadowed is made aginst a volume, not a point. Add to that the shape of the light emitter and you have soft shadows.
Soft shadows are the easiest way to add, err, soft shadows! You will also need to set the radius. For a distant light, you need to set it quite high, try 100 or even 200 feet, the higher the figure, the softer the shadows. If you make it very large, you may be able to see banding, in which case increase the quality setting. For bulb and spot lights, the effect will be related to the position and distance of your light from your subject and will relate to real life examples, so for instance set it to 1ft for a spot that is around 1ft across.
Oh, yes, because workaround is one of the best (yet underappreciated) Carrara's undocumented features
If you use Studio and its native renderer, 3Delight, that is also a biased renderer and lights work the same way. It is just the jargon that is a bit different between the two programs. For instance, if I recall correctly a bulb light in Carrara would be a point light in Studio.
Snarkiness aside, workarounds are common in all sorts of programs, not just Carrara. When you get right down to it, aren't 3rd party plugins essentially workarounds that someone creates to address a shortcoming, or missing feature in a piece of software, and then gets paid for selling the workaround to other people?
Here's a render with a single distant light with soft shadows enabled, and light radius set to 1800. And fast quality.
I think it has a certain "soft shadows awesomeness" to it
There's also an option to team Carrara with say Photoshop and blur the shadows using a shadow render pass. That way you can separate out just the shadows and have total control over how the shadows appear (blur, color, etc.)
And here's the shadow pass for the above image. If nothing else it's instructive because it shows you ONLY what the shadow part of the image is. And you can clearly see the "Banding" in the cast shadows, while it might not be evident in the final render.
If you wanted you could take that shadow pass, which is packaged with the image, into Photoshop and blur it by hand to remove the banding, rather than playing with quality settings.
Just one other option.
And here's a quick shadow pass smudgy/blur to show how you can quickly make your shadows nicer and remove the banding.
In fact you could even take a hard shadow and blur it by hand to get soft shadows if you find the soft shadow calcs are taking too long.
Again, just another option.
all good stuff, thanks for asking OP, I relearnt stuff that I had forgotten ;)
I just use "fake 'gi'(?) "
Recipie follows:
Take One distant light as the sun - 100 percent light value and 100 percent shadows - make the light yellow
Duplicate that - make the duplicate a blue colour , reduce intensity to 10 percent, adjust the angle slightly but still have it pointing down, make shadows 12 percent.
Keep duplicating this light till bored (eg 5 times ;) ) these lights become the reflected light from the sky and will fill in the shadows of your main light with blue
End product: this will give you your skylights with ' soft' shadows
you need to tweak the numbers untill happy - eg main light might be 125 percent depending on how dark the yellow colour is
then you need ground lights to mimic reflected light from the ......... ground ;)
Sooty shadows are a real problem in 3D and generally my whole lighting strategy is geared toward avoiding them. I like using a "Light Hemisphere", i.e., a replicated light placed on a hemi shape. If you dial the replicated light's intensity way way down, with Hard Shadows, you can soften shadows and remove the sootyness, still leaving your main lights to do their job. Hard Shadows computes almost instantly so adding 100 lights to your Hemi won't cost ya much in render time, even with GI and IL turned on. They also create a bit of AO... for free.
Play around with it. Takes a while to get used too, but works very well for me.
- Don
Sooty or ashing in the shadows is a byproduct of GI, and not soft shadows. Soft shadows can have banding issues as has been mentioned.
The light dome Dondec mentioned is a great way to simulate GI, but depending what is in the scene, such as a lot of trees, items with trans-maps such as figure or prop hair, and dynamic hair, and how many replicated lights that are used, it can slow down to nearly the point of using thew skylight or full Indirect Light.
Speaking of GI and specifically Skylight, which is a partial GI, it's a great way to get the diffuse, soft shadows created by atmospheric light without a huge hit in light calculations. I would still say, generally speaking, you would need a distant or sun light for highlights, but the brightness may be able to be reduced, and if you add soft shadows to it, you can get a very realistic look.
So, it sounds as if you are coming at this from Studio, so I don't know if this can be done in Studio or not... As you know, soft shadows can really increase the render times, depending on what is in the scene, and if you have multiple lights with soft shadows, it can really go up. What I do in many cases is use light linking, which is basically including and excluding objects in your scene from particular lights.
Let's imagine you have a scene with a character with dynamic hair, and two lights with soft shadows, Lights A and B. When the render tiles hit that part of the scene it slows to a crawl. To solve the problem, you can set up Light A with your light intensities, falloff, soft shadows, etc. Then in the light's general tab, exclude the hair from the light. With Light A selected, either press Command+D, or go to, File--> Duplicate, to duplicate the light. Change the little bullet above where hair is selected from Exclude, to Include, and then in the Effects tab, turn off soft shadows. Do the same thing for Light B. The duplicated lights will be in the exact same position to the original lights.
It's not really a workaround. The technique of splitting the sun into two lights is called a key and spill light and is a classical way of simulating sun light.
From Jeremy Birn, author of Digital Lighting and Rendering, 3rd Edition
Don’t Forget the Spill Light
A spill light is one of the lights that’s most often missing from 3D renderings. A spill light is just a light coming from roughly the same direction or position as your key, but made more soft so that it covers a broader area than the key itself. A spill light around your key can make your rendering look much more natural and believable.
If you add a sunbeam to an interior rendering, the sunbeam will look better with a soft spill around it. After you have your main sunlight set up, and you have test-rendered it to make sure you like what it illuminates and where it casts shadows, you can duplicate the sunlight and rename the copy to become a spill light. Leave the spill light aimed the same direction as the sunlight, but set it to have much softer shadows, so that it spills out beyond the edge of the sunbeam. Make the spill dimmer than the sunlight itself. In some scenes, it is useful to give the spill a richly saturated color. For example, around sunset, the sun itself might be an ordinary yellow, but the spill could be a rich red or deep orange.
In my Hemlock Folly scene, I have a "Fake GI" light dome (I actually use a sphere primitive with a replicator mask so only the top half gets used). It produces a nice diffuse effect, although I find it does need an extra uplight for under tree canopies. BUT as the scene has become increasingly more complex & stuff gets dialled up to "11", the time benefit over "Skylight" has diminished to the extent that a Skylight render is often faster. I've never tried a full GI render on the scene, because the computer isn't dedicated to just 3D and life's too short.
I'm interested in Dondecs comment regarding lots of lights and hard shadows. That's a tweak I'll give a try over the weekend and see what difference it makes. (the machine is spitting out iRay renders right now, and these take even longer, cos they blow my tiny graphics card's memory!)
Tim_A, I'm a programmer and think in terms of "procedures" for doing repetitive things. This is what I came up with for my renders.
* Create your scene, setup basic intuitive based lighting like Sun or Practical lighting for indoors, then turn them all off and:
* Create a sphere or more preferably a "pill" shape the size of a human, set the color to 127 grey in the center of your scene and camera frame
* Introduce a hemi rig, turn the replicated lights down, use hard shadows at 100%, Scene Ambience OFF,
* I use Gamma 2.2.
Repeatitively rerender and sample the shade of the rendered sphered/pill. Try to get a 127 grey color back, at least in the center (where the polys are most facing the camera) This is how I calibrate my lighting... get it to return its own original color first with good looking, non-sooty shadows (that's controlled by the number of replicated lights).Once you have that, turn the hemi rig off and adjust your practical/Sun lighting to do the same... return 127 grey. Now your're working with "knowns".
I innitially hold the replicated light at 20% brightness then adjust its color darker until I get the 127 grey color back. Now its calibrated, I know, 20% brightness returns the original color. Higher than 20% adds brightens, less than 20% darkens. 20 always returns the original.
Now combine practical/Sun and hemi to suit your scene. The hemi rig is used to soften shadows and fill in darker regions.
I use between 80 and 120 replicated lights. Save the whole rig including the test Sphere/pill when its calibrated. Do pay attention to where your replicated lights are pointing, if using Spots or Distance lights. That's the basic idea. Hope this helps.
- Don
Tim I've not done a heavily wooded scene like I saw you post recently. But for rooms and outdoor scenes I've had good luck. One other thing, if you are able to make the floor not cast shadows (just receive), that can help with shadows closest to the floor (around feet).
- Don
Dondec, that's an interesting "calibration" procedure for your lights.
I'm not sure the ultimate purpose of the procedure though. What are you trying to accomplish?
Thanks.
I use the Hemi rig to soften shadows and fill in darker regions... more control, eliminate sooty shadows, provide natural AO.
Don't over think this JoeM :) ... just give it a try... see if you find it helpful.
- Don
No, I understand the big hemisphere of lights. People (including me) started doing that way back in the dark ages to get soft shadows when processors were slower than molasses in January. Thick molasses.
I'm just trying to understand the goal behind all the calibration of 127 (mid-gray). Just curious what you're going for. Actually I'm trying to under-think it cuz it seems like a lot of work. Maybe there's an easier way if I can understand you goal. Just trying to help.
Haha gotcha. Ok. Well for me, I work better with "procedures", and I hated fooling around with lights every darn time to solve shadow problems. First I tried using a Hemi light rig, and it seemed to work really well for figures, removing shadow issues. But every time I used it I was "fooling around with lights" again.
The 128 grey stuff gives me a handle, a reference point from which to start. If I calibrate it as I suggested, then drive it at say the 20% brightness level, which I already know returns the same color as the original texture mats (or close to it), I can work upward or downward from there. Usually upward, since I've been doing a lot of Sun lit things. But I always START at 20% see.
For outdoor things in bright light I found Sun strengths of 200-300% looked most natural to me as "sunlight". That coupled with 30-40% brightness on my Hemi rig, especially for characters, seemed to repeatedly solve any annoying shadow issues. The repeatability was a surprise. No fooling around.
In one other test, where my figure was completely shaded (under a tree) I used no Sun or Sky and only the Hemi because it created even lighting without strong shadows. There 20% or close too it was all I needed.
Now I do use the Hemi with GI... this is not a fake GI thing. It smoothes out your existing lighting and creates a better GI render. Also because you're adding extra "low intensity lights" in the scene Ive discovered you can reduce the GI render settings near rock bottom and still get great results... no blotchness.
So that it really. Make sense?
- Don
I've done a "quick" back of a napkin experiment using an outdoor scene (attached) with a large number of trees (poly leaves), ground cover plants (mix of poly and transmapped leaves) and reflective water. I've rendered the scene twice, varying just the hemisphere lights. The general lighting and render setup was as follows: Realistic sky, sunlight @ 60%, hemisphere replicated lights adjusted to give an overall value of 200% (40 lights at 5% or 100 lights at 2%). In the RayTracing section, Tranparency and Light Through Transparency are set, Gamma is set to 2.2., AA/OA/SA are set to Good / 0.5px / 1px. All GI is off. Machine used for the render is an i5 Mac at 3.2GHZ, 8GB RAM. Image rendered at 800x500.
Aesthetically, the scene may look better with the light settings reversed (ie sun at 200% and dome at 60%), but for the purposes of this test I just went with whatever the scene had last been saved at. As has already been pointed out, this is a complex and dense scene and similar results may not be reflected in smaller, less dense scenes.
Render 1 (40 lights @ 5%): 3 hours 55 minutes
Render 2 (100 lights @ 2%) 10 hours 4 minutes
Now, these are just 2 data points and the correlation may not be linear, but at a quick glance it appears that for every 10 lights in the dome, render time increases by an hour.
Yeah Tim_A, after seeing your results I went back to my scenes. Seems I was using this Light Rig on relatively low poly setups, or at least setups without a bunch of replicators. When I tried it on Byodo In which has a ton of trees and leaves, even a postage stamp render crawled (or hung) using 100 bulbs, Photon 1000 @ 2%, Light Qual Fast 4 px.
I guess for these types of scenes Fake GI seems a must.
I'm going to try a few more things, but that's all I've got at the moment.
- Don
It sounds like you are combining fake GI techniques (lots of lights) with actually turning GI on, which sounds like a recipe for long render times. I think you should do one or the other, but not both at once.