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Depth of Field - any tricks to speed up render?

jrm21jrm21 Posts: 140
edited January 2017 in Carrara Discussion

I am in the process of rendering a simple animation and want to use depth of field. Without DOF, frames were rendering in about 15-30 sec each. With DOF turned on it is over 10 minutes per frame. (Then after about 100 frames, Carrara locks up and needs to be force-quit. I am rendering as squenced images, so I can pick up where it left off).

 

I understand that DOF requires extra processing power. Are there any tricks or tips to speed up the render? Is there a way to handle the DOF in post, using different software (Mac based)? (I know how to do this with stills, but don't know if it can be done with animations/hundreds of frames)

Post edited by jrm21 on
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Comments

  • DUDUDUDU Posts: 1,945
    edited January 2017

    It's very strange, the DOF is calculated after the "normal" render and usually takes one or two seconds, depend on your DOF settings.

    The Carrara DOF has not a good quality and isn't so precis, if you could make a multi-pass render and use the compositing, it's far better...

    It's the same process for animation, the only think is to make your passes with the same camera if it is animated.

    Post edited by DUDU on
  • jrm21jrm21 Posts: 140
    edited January 2017

    Hmmm... from what I read, I though DOF was supposed to take a long time. Today, I have gone through 40 frames in 8 hours. WIthout DOF, the entire 15 second/30 fps animation rendered in uner an hour. From the frames I have seen so far, Carrara's DOF would be fine for my purposes. I was just hoping for a way to speed things up.

    Maybe I am misunderstanding how to create DOF in post. I can't test it now because Carrara is still rendering - another 80 frames to go. (16+ hours at this pace).

    I thought the process was to muli-pass render a depth map. Can't recall if that's a separate file or an alpha channel. Either way, simple enough to load the channel as a selection and apply a blur in Photoshop. Would I just create a PS action and batch process to run on each frame before turning the sequence into a moving file? Is there a better way to do this? Can it be done inside an NLE after the images are combined into a sequence?

    Post edited by jrm21 on
  • PhilWPhilW Posts: 5,145

    I think your best bet is to render a depth pass and do the DoF in postwork. Failing that, don't use RayTraced DoF for animations, it takes too long - play with the settings (intensity and quality) to get the best effect you can on a single frame without it taking too long.

  • DartanbeckDartanbeck Posts: 21,532
    PhilW said:

    I think your best bet is to render a depth pass and do the DoF in postwork. Failing that, don't use RayTraced DoF for animations, it takes too long - play with the settings (intensity and quality) to get the best effect you can on a single frame without it taking too long.

    My favorite option is to use rotoscoping techniques in Post, applying my depth of field and/or other blurs in Holwer.

    Rotoscoping is a curve which we can animate along a timeline. Then we can either work with pixels inside or outside the curve throughout the timeline. And in Howler, we can also animate the effect that we're applying as well - so we can go from no blur to full blur, for example, as well as a bunch of other effects.

    My biggest reason for starting doing it this way was to save time. Now I prefer it because of the control I get in the process. During render, we have to wait - and re-render if something comes out incorrectly. This way, we render faster, getting that phase done. Then we can adjust the effects in a more real time environment - post.

    But don't take this as me trying to switch your techniques. Carrara also allows us to animate the amount of DoF and does a beautiful job of it - it just taxes the render time is all. These were part of the reason why I stayed at 1280 x 720 (720p) instead of jumping to the higher 1080p, which takes a considerable amount more time to render.

  • jrm21jrm21 Posts: 140
    edited January 2017
    PhilW said:

    I think your best bet is to render a depth pass and do the DoF in postwork. Failing that, don't use RayTraced DoF for animations, it takes too long - play with the settings (intensity and quality) to get the best effect you can on a single frame without it taking too long.

    I don't have full raytracing activated. I do have skylight turned on with an HRD background in use. I had render times down very low and didn't expect DoF to add so much time. It's now almost 13 hours into the lastest render segment and working on frame 54.

    I'm figuring that DoF in post is the way to do. Just not sure how to do it. I can render a depth pass. It that done as an alpha channel in the file? If so i could proably work out a PS action to automated it. Is there an easier way? 

     

    Dartanbeck said:

    My favorite option is to use rotoscoping techniques in Post, applying my depth of field and/or other blurs in Holwer.

    Using a Mac over here. Howler doesn't seem to be an option.

    Dartanbeck said:

    My biggest reason for starting doing it this way was to save time. Now I prefer it because of the control I get in the process. During render, we have to wait - and re-render if something comes out incorrectly. This way, we render faster, getting that phase done. Then we can adjust the effects in a more real time environment - post.

    Howler aside, is there a way to do this in real time in other software? Photoshop? After Afffects? Motion? FCP X? I have all of those. 

    Dartanbeck said:

    But don't take this as me trying to switch your techniques. Carrara also allows us to animate the amount of DoF and does a beautiful job of it - it just taxes the render time is all. These were part of the reason why I stayed at 1280 x 720 (720p) instead of jumping to the higher 1080p, which takes a considerable amount more time to render.

    No - PLEASE switch my techniques. :) I am very pleased with the results from Carrara, just don't want to spend 4-5 days on a 15 second clip render. If there is a shorter method, I am all for it. Guess I should have stuck with 720 instead of jumping to 1080. Again - it is a simple scene that rendered quickly. I had no idea DoF would cause such an increase in render time.

    Post edited by jrm21 on
  • DartanbeckDartanbeck Posts: 21,532
    edited January 2017

    Howler aside, is there a way to do this in real time in other software? Photoshop? After Afffects? Motion? FCP X? I have all of those.

    Yes! All of them, I think. Find the one that is the most comfortable for you to figure out how to make animated selections in - because that is key.

    An option beside rotoscoping is to use multi-pass rendering to make these selections for you in the form of grayscale images - but that's harder for me to explain - especially since I don't have any of those software options.

    Speaking of using Sky Light and HDR in the background, we can also achieve a blurry background by using lower resolution backgrounds, but with a lot less control.

    Post edited by Dartanbeck on
  • DartanbeckDartanbeck Posts: 21,532
    jrm21 said:
    PhilW said:

    No - PLEASE switch my techniques. :) I am very pleased with the results from Carrara, just don't want to spend 4-5 days on a 15 second clip render. If there is a shorter method, I am all for it. Guess I should have stuck with 720 instead of jumping to 1080. Again - it is a simple scene that rendered quickly. I had no idea DoF would cause such an increase in render time.

    Well... while we're on the subject, I'd like to add that:

    There should be very few (if any) reasons to make such a long render. Even for a showing of continuous motion - going somewhere or whatever, doing so in several renders of shorter 2 to 5 or 6 second shots almost always looks a lot better in the end to the audience. Almost always.

    Split up the time using different cameras at different angles and make each render for only a few seconds, then load these sequences all into the Batch Queue render option, selecting the appropriate camera and time frame separately for each listing of the scene file in the queue.

  • jrm21jrm21 Posts: 140
    edited January 2017
    Dartanbeck said:

    Well... while we're on the subject, I'd like to add that:

    There should be very few (if any) reasons to make such a long render. Even for a showing of continuous motion - going somewhere or whatever, doing so in several renders of shorter 2 to 5 or 6 second shots almost always looks a lot better in the end to the audience. Almost always.

    Split up the time using different cameras at different angles and make each render for only a few seconds, then load these sequences all into the Batch Queue render option, selecting the appropriate camera and time frame separately for each listing of the scene file in the queue.

     

    Understood, and point well taken. 

    This particular item is just a simple particle generator spewing cubes. They are guided by a force. Force moves through the scene and camera follows. If it comes out the way I hope, it will be a b-roll for something I am working on (mostly live action). I ran it out to 15 seconds to get some variety in the shot. It would be a recurring image in the final product and I didn't want the same exact thing each time. In the end, this would be cut up into 4-5 separate pieces, each much shorter. One other possible use was going to be as an overlay on a longer section of the final video, where I would need about 10 seconds.

    So, yes, I get the concept of working in shorter pieces. For what I do, 5-10 seconds is the norm. With the way the particles evolve in this scene, I went to 15 seconds. As Carrara seems to lock up every 80-100 frames, I technically rendered 3-4 scenes of about 5 seconds anyway. :) Looks like that old render problem still exists - seems it starts taking about 9min/frame. After about 50 frames it is up to 20min/frame. Time keeps going up until things lock up. Another good reason to work in much shorter sections. That's also why I always render as sequenced images - you can easily pickup where you left off.

    Dartanbeck said:

    Speaking of using Sky Light and HDR in the background, we can also achieve a blurry background by using lower resolution backgrounds, but with a lot less control.

    I tend to use the old "Dimension Theory" HDR backgrounds from the cloud set. The ones I have provide a "detail" version and a "blurry" version. While I have had render success with both, the author noted that the "blurred" versions helped shorten render times. I think this ties in with you advice. The less detail (or resolution)  in the background, the less impact on render time.

     

    Once this is done, I will render one frame with a depth channel to see how Carrara handles the file. Then I guess I'll drop by the PS, Motion and AE sites to see how to work that format to create DoF in post.

     

     

    Thanks

    Post edited by jrm21 on
  • DartanbeckDartanbeck Posts: 21,532

    Awesome!

    Particles, eh?

    They, too, can be a good source of render slow-down/computer lock-up. It's always a juggling act between how many we emit and how long we allow them to stick around, along with how many (max) we allow to exist at any one time.

    Since we can ask particles to do any enormous amount of calculations, like collisions and respecting forces, we can easily tax our computers to the end of their allowed memory. 

    What you're doing sounds cool!

  • cyborgty_074ff6c243cyborgty_074ff6c243 Posts: 132
    If you use the Octane render plugin, shots with depth of field are rendered quite fast. But if using Carrara's renderer, I always used depth pass and use After Effects 'camera lens blur'. You should set the 'Blur Map' layer to the layer with your depth pass sequence. You could then set the Blur focal distance as desired.
  • FifthElementFifthElement Posts: 569
    edited January 2017
    jrm21 said:

    I don't have full raytracing activated. I do have skylight turned on with an HRD background in use. I had render times down very low and didn't expect DoF to add so much time. It's now almost 13 hours into the lastest render segment and working on frame 54.

     

    I reckon you are talking about render setting (Render room: Full Raytracing check box) so to just set the record straight, I think PhilW was talking about Raytraced Depth of Field setting in Camera properties (under Effects tab).

    Here is the screenshot:

    Non-raytraced DOF in Carrara should not take more than a second (maybe few, depending on image size), because it is using a depth pass to make it so (not a good implementation, but, it works), raytraced one works with reflections and refractions and it is fully accurate but it takes a very long time, I used it few times myself, I prefer "fake"" one in stills and animations.

    Fusion (free software) does a OK job with depth pass from Carrara (which in itself is not that good, lots of banding in it and it is not antialiased).

    I prefer making my own "depth pass" using Sparrowhawke3D's Distance Falloff Shader applied to all my objects in the scene, much easier to control in Fusion (or software of your choice).

    Here is download page: http://www.sparrowhawke3d.com/Sparrowhawke3DLaboratory.html

    Cheers smiley

    CarraraDOF.jpg
    513 x 324 - 45K
    Post edited by FifthElement on
  • FifthElementFifthElement Posts: 569
    edited January 2017

    Double post, lol smiley

    Post edited by FifthElement on
  • TGS808TGS808 Posts: 168
    cyborgty_074ff6c243 said:
    If you use the Octane render plugin, shots with depth of field are rendered quite fast. 

    Pretty sure the answer he was looking for didn't include having to buy another render engine for $400.

  • FifthElementFifthElement Posts: 569
    TGS808 said:
    cyborgty_074ff6c243 said:
    If you use the Octane render plugin, shots with depth of field are rendered quite fast. 

    Pretty sure the answer he was looking for didn't include having to buy another render engine for $400.

    Yep, lol, when people brag about having Octane, I always remind them that Bleder and it''s Cycles renderer are totally free smiley

  • jrm21jrm21 Posts: 140
    edited January 2017
    Dartanbeck said:

    Particles, eh?

    They, too, can be a good source of render slow-down/computer lock-up. It's always a juggling act between how many we emit and how long we allow them to stick around, along with how many (max) we allow to exist at any one time.

     

    I love playing with particles. Unfortunately, somewhere between C7 and C8.5, they became a real issue on my system. Simple particle scenes used to run and render extremely quick. I remember running some of Dimension Theory's "light with particles" scenes and never saw any slowdown. I could run them in real time. That changed and no matter what setting I now use, the "calculating" progress bar rears its head and brings things to a crawl. I asked about this in the forum and entered a support ticket years ago. Neer received an answer or response to the ticket. Seems that's just how it is. It's a big reason I don't use Carrara much.

    Dartanbeck said:

    What you're doing sounds cool!

    Thanks.

    FifthElement said:

    I reckon you are talking about render setting (Render room: Full Raytracing check box) so to just set the record straight, I think PhilW was talking about Raytraced Depth of Field setting in Camera properties (under Effects tab).

     

    Ahh... thanks for the clarification. I was thinking the render room setting.

    However, I just checked my DoF seting and rarytracing was turned off. I religiously avoid any setting in Carrara that has the word "slow" attached. :) Since I am interested in animations, render speed is the priority.

    FifthElement said:

    Non-raytraced DOF in Carrara should not take more than a second (maybe few, depending on image size), because it is using a depth pass to make it so (not a good implementation, but, it works), raytraced one works with reflections and refractions and it is fully accurate but it takes a very long time, I used it few times myself, I prefer "fake"" one in stills and animations.

    I must be doing someting very wrong. Here's some info and an idea of render times:

    image size = 1920x1080
    4 objects, 2 lights

    basically a particle generator with two cube objects as the particles. Particles pulled by a force with camera following.
    Maximum 1500 particles with a 15 second life.

    I rendered two random frames. One toward the start and one later on in the sequence.

    Frame 1:
    Simulating Particles: 6:55
    Render frame: 0:03
    DoF: 0:35

    Frame 2:
    Simulating Particles: 14:45
    Render frame: 0:15
    DoF: 3:30

    I may have been wrong in my claims about quick renders with DoF turned off. The render was going when I was away from the machine. When I got back, it was done. I looked at the statistics and forgot that it only includes render time (which is very quick). It doesn't count the "simulating particle" time, which can be quite long. 

    So it seems that the particles are my biggest time problem. Still, DoF is considerable more than a few seconds. Kind of crazy that both are so much greater than the actual render time.

     

    FifthElement said:

    Fusion (free software) does a OK job with depth pass from Carrara (which in itself is not that good, lots of banding in it and it is not antialiased).

    I prefer making my own "depth pass" using Sparrowhawke3D's Distance Falloff Shader applied to all my objects in the scene, much easier to control in Fusion (or software of your choice).

    Here is download page: http://www.sparrowhawke3d.com/Sparrowhawke3DLaboratory.html

    Cheers smiley

    Thanks. I will take a look at both those options.

     

    edit: looks like the Sparrowhawke3d isn't an option for me. The plug-ins are marked as Window 32 or 64 - no Mac version.

    The Carrara depth pass will hopefully be good enough for my purposes. I just tried a quick single frame render with depth pass. Easy enough, and adds no tnoticable ime to the render. I see the alpha channel in PS and understand the shades of grey represent distance. What I am not sure is how to apply that to a DoF effect across multiple files. Maybe PS isn't the right tool for this. I'll take a closer look a Fusion.

     

    Edited to add: PS - just noticed the "lens blur" filter which can use the alpha channel to create a DoF effect. For some reason, I had my head stuck in a Gaussian Blur mode. :) Lens Blur makes it simple and I'm sure I could create an action that runs through Bridge to process multiple frames. I'll also take a look at Fusion (but it seems like a steep learning curve and might be overkill for what I am doing)

    Post edited by jrm21 on
  • jrm21jrm21 Posts: 140
    FifthElement said:
    TGS808 said:
    cyborgty_074ff6c243 said:
    If you use the Octane render plugin, shots with depth of field are rendered quite fast. 

    Pretty sure the answer he was looking for didn't include having to buy another render engine for $400.

    Yep, lol, when people brag about having Octane, I always remind them that Bleder and it''s Cycles renderer are totally free smiley

     

     

    $400! Correct, I wasn't looking for that kind of option. At that cost, I could hire a local graphic artist to deliver several final products and save myself the trouble. :)

    Blender is something I also looked at. Heard great things. Just have so much going on right now there is no time to figure it out. Seems to have a bit of a learning curve. At some point I will make time to go through some of the tutorial videos.

  • TGS808TGS808 Posts: 168
    edited January 2017
    FifthElement said:
    TGS808 said:
    cyborgty_074ff6c243 said:
    If you use the Octane render plugin, shots with depth of field are rendered quite fast. 

    Pretty sure the answer he was looking for didn't include having to buy another render engine for $400.

    Yep, lol, when people brag about having Octane, I always remind them that Bleder and it''s Cycles renderer are totally free smiley

    And, really, it's not even as much about the money as it is a non-answer. When someone asks for tips on using DOF in Carrara, telling them to render in Octane is not an acceptable answer.

    It's like if someone said they were planning a road trip across the country and asked for some tips on best routes to drive and the answer they get back is "if you take a plane it'll be faster".

    Also, last I checked there was no Octane plugin for Carrara on Mac. I don't know what platform jrm21 is on but if it is Mac he's out of luck on Octane either way.

    Post edited by TGS808 on
  • DartanbeckDartanbeck Posts: 21,532

    I love playing with particles. Unfortunately, somewhere between C7 and C8.5, they became a real issue on my system. Simple particle scenes used to run and render extremely quick. I remember running some of Dimension Theory's "light with particles" scenes and never saw any slowdown. I could run them in real time. That changed and no matter what setting I now use, the "calculating" progress bar rears its head and brings things to a crawl.

    Really?

    I have a copy of 6 and 7, perhaps I should install one just to use as a particles simulator. Certainly wouldn't hurt to try. 

  • jrm21jrm21 Posts: 140
    Dartanbeck said:

    Really?

    I have a copy of 6 and 7, perhaps I should install one just to use as a particles simulator. Certainly wouldn't hurt to try. 

     

    That sounded like a good idea. Carrara 7 is actually still available for download in my account. Just tried it. Incredibly unstable on my system (no surprise considering C7 is probably four Mac OS updates ago). It won't "hold" my serial number - must enter on each launch.

    Anyway... no joy. The slowdown still exists. I though I tried that before... probably why I can't remember when the problem started. It seems to be related to a system update rather than a Carrara update.

    When you wrote "perhaps I" you meant me, right? Or are you also having problems with particles? I always found it odd that there wasn't more talk of this issue.. Am I the only one using particle generators on a Mac? 

  • DartanbeckDartanbeck Posts: 21,532

    LOL!

    I actually meant "me" just to see.

    Yes, particles really seem to tax my render times.

    My work-around is to try and use shaders that allow me to use larger particles and less of them. Still spitting them out at a good rate, but more in the hundreds instead of in the thousands.  So I also make use of that cool size over life curve tool. Love that thing. Make my particles sizes really quite large, then set the size over life curve way toward the bottom of the graph on the left side, and then determine how quickly I want them to jump (or gradually grow) to full size, which brings up another part of my workflow, which is to try and have the particles last only as long as I need them, them have them disappear - so I also try to weight out how many total particles I will allow to live at any one time.

    In the end, I can usually get decent render times, but nowhere near as fast as they are without particles - to say the least. But particles... gotta have particles! Sometimes they're just worth the wait.

    Part of my big reason for wanting to get HitFilm Pro is so that I can have their cool particles system. I do have Fusion (free version) which also has a good particle system. So I'm just entering the learning stage of adding my particles work outside of Carrara altogether, except for those times when I really need them in Carrara.

    But both Fusion and HitFilm Pro allow us to place deflectors within the system, so we can actually make them appear as if they're interacting with out animation renders, even though they're added as Visual Effects in post. The real-time feedback is really beneficial too. I just haven't reached a point where I'm doing it in post yet - which is the only reason why I'm still kind of unfamiliar with how to use particles in Fusion.

    I know how - in theory - just haven't earned my way via the experience of doing it yet - which makes a HUGE difference. ;)

    All of that said, and Carrara being the Swiss Army Knife that it is, I'm really quite impressed with how good the particles system is in Carrara. I haven't had the courage to run an advanced simulation with secondary spawns on contact and such, but that's where I was planning to go with fluid simulation when I needed that, but the metaball particles worked beautifully without the need for the advanced spawns... so I still didn't need to take that plunge. One day... one day!

  • jrm21jrm21 Posts: 140
    edited January 2017

    Sounds like some very cool and fun stuff you are doing.

    Dartanbeck said:

    All of that said, and Carrara being the Swiss Army Knife that it is, I'm really quite impressed with how good the particles system is in Carrara. the advanced spawns... so I still didn't need to take that plunge. One day... one day!

     

    Agreed complelety. I have always had fun playing with particles in Carrara. So many options and so many things that can be done. As much as I complain about the interface, it is farily intuitive. You can get results quickly.

    That's why I was so dissappointed when the problems started. I used to be able to run thousands of particles in realitime. As noted above, a simple scene with 1500 particles can take up to 15 minutes just to simulate in the render room. When building the scene I have to turn off particles in 3d view. Even at a 20% view setting, it can take a minute or more for the screen to draw.

    Haven't tried Fusion yet, but I decided to take a look at "Blender" (it was mentioned earlier in this thread). The interface is IMO, insane (not in a good way). :) After a few video tutorials, I have my head wrapped around the basics. I was pretty amazed at their particle system. I ran some test renders with 10,000+ particles... view window runs pretty much in realtime. Renders are very fast and look good (even with DoF activated). Worth a look if you want some fast particle generation.

     

    Edtied to add: Just realized that nav bar at the bottom of your message is not an ad. :).  I looked at your "My Carrara Animation" link... VERY nice work. You are doing some very cool things with Carrara.

    Question - how long did it take to render that short sequence at the beginning with the flyover in "Mystic Gorge?" I always liked that model, but have never been able to get it to render at an acceptable speed.

     

    Post edited by jrm21 on
  • WendyLuvsCatzWendyLuvsCatz Posts: 38,190

    https://www.renderosity.com/mod/tutorial/?section_id=16

    I have also seen one using Hitfilm

  • DartanbeckDartanbeck Posts: 21,532
    the3Ddigit said:

    https://www.renderosity.com/mod/tutorial/?section_id=16

    I have also seen one using Hitfilm

    Absolutely! I use Howler, but I've also done this (DOF in post) in HitFilm as well... very cool!

    My favorite part is that we can easily change the DOF throughout the sequence, or try other results, ect., without having ti render all over again! ;)

    Thanks for the link, Girl Friend! :)

  • DartanbeckDartanbeck Posts: 21,532
    jrm21 said:

    Sounds like some very cool and fun stuff you are doing.

    Dartanbeck said:

    All of that said, and Carrara being the Swiss Army Knife that it is, I'm really quite impressed with how good the particles system is in Carrara. the advanced spawns... so I still didn't need to take that plunge. One day... one day!

     

    Question - how long did it take to render that short sequence at the beginning with the flyover in "Mystic Gorge?" I always liked that model, but have never been able to get it to render at an acceptable speed.

    Well... I was fairly new with Carrara when I rendered that sequence. It didn't take very long to render at all... but I did a LOT of cheating.

    I was still unfamiliar with the power of Carrara's realistic sky/sun light system, and shut it off

    I also removed most of the distant terrain and such

    Then brought in my Skydomes scene that I made, which contains all of the skydomes I've collected in a single scene, each set up to Glow correctly for my liking, then all are made invisible except for one - the main sky that I used most often.

    I think that the time-consumer in that scene would be the volumetric clouds. Shut those down and try it. I've always been amazed at how quickly I can render that scene... but I can't always remember waht all I did to change it! LOL

    I do know that it was the first Carrara scene to recieve the water shader that is now in my EnvironKits as the High Quality version. Being from Wisconsin, surronded by freshwater lakes instead of coastal oceans, I'm not used to seeing Caribean Blue waters - so that was one of the first changes I made - and I used the ocean primitive instead of the water plane the scene comes with.

  • DartanbeckDartanbeck Posts: 21,532

    Oh... and Thank you for the compliments! :)

  • jrm21jrm21 Posts: 140
    edited January 2017
    Dartanbeck said:

    Well... I was fairly new with Carrara when I rendered that sequence. It didn't take very long to render at all... but I did a LOT of cheating.

    All good tips. Don't ever call it "cheating." It is simply being smart. What else would you call getting desired results in less time? I'll give your ideas a try. Thanks.

    Post edited by jrm21 on
  • PhilWPhilW Posts: 5,145

    Just caught up with this thread - I am almost certain that the main issue is the particles and not the DoF (although that's adding some time). As I recall, each frame you render, it recalculates the particles FROM THE BEGINNING!  So for a short sequence, it isn't too bad, but the longer the sequence, the more and more time each frame takes to render because it is recalculating all of the particle movements up to that point.  So keeping your particle clips as short as possible is definitely recommended.

  • jrm21jrm21 Posts: 140
    edited January 2017
    PhilW said:

    Just caught up with this thread - I am almost certain that the main issue is the particles and not the DoF (although that's adding some time). As I recall, each frame you render, it recalculates the particles FROM THE BEGINNING!  So for a short sequence, it isn't too bad, but the longer the sequence, the more and more time each frame takes to render because it is recalculating all of the particle movements up to that point.  So keeping your particle clips as short as possible is definitely recommended.

    Thanks, Phil. You are correct... it apparently was the particle emitter that was causing the bulk of my slowdown. I didn't realize that at first, because my initial render (without DoF) was done unattended. When DoF was turned on is when I noticed the big jump in time.

    See above for stats... a frame that rendered in 15 seconds had almost 15 minutes of "simulating particles" for each frame.. that was only about 7-8 second into the animation. Hard to get the desired particle effect want with something much shorter than that. It also had 3:30 for the DoF. Someone mentioned that D0F should add a few seconds, so I think that number may also be out of line.

    Calculating particles from the beginning for each frame would explain the slowdown. I still feel that 1500 particles taking 15 minutes is excessive.

    Are these times normal? Or am I doing something wrong? 

    If normal, are there any workarounds? Easy enough to cut down DoF by handling it with a map in post (thanks for the tips here). What about particles?

     

    Post edited by jrm21 on
  • PhilWPhilW Posts: 5,145

    If you have seen my Waterfall animation in another thread, that uses 50,000 particles on a ten second animation and the average render time was less than 5 mins per frame, and a lot of that was due to the refraction through the water, and not the particle calculations, so yes your times seem excessive. Maybe it is complex interactions that the particles are undergoing?

  • DartanbeckDartanbeck Posts: 21,532

    I wonder if the shaders are intensive vs the render settings too. Like Global Illumination with full indirect lighting with light through transparency with reflections and refraction and caustics, perhaps blurry reflections? Oh... and do the lights use soft shadows? 

    I always say how FAST Carrara's render engine is, and that's true. But I've dedicated some years of pretty hefty experimentation on reducing render times - learning what I can sacrifice and where. For example, while everybody says "never use Ambient feature", yeah... screw that! I do use it, but I'm also very aware of what it does - so I know when I need to shut it down - and I know to use it very much on the subtle side - like Age of Armour suggests, keeping the color chip very dark.

    So I have taught myself to not rely on any auto-realism by default, like GI, IL and only using reflections if I need to 'see' reflections in the material. Shiny doesn't require reflection, and transparency doesn't always require refraction. I do use all of this stuff... but I am careful to know exactly what each of my shaders are doing for each of the lights. 

    The thing that excites me about the speed of Carrara's render engine is that it does give us ways to get these very speedy renders and still get a good result, where some other render engines won't give us nearly as much contol - or make such controls difficult to access.

    If I really ned soft shadows but I also really need speed (sometimes I just allow for longer renders) I go for shadow buffers instead of ray tracing. When doing that, cranking shadow buffer resolution wide open does not equal best results. Again, I learned from, I think it was Age of Armour, or was it Dimension Theory, that we go through a test process to determine the best softness. Shadow buffers can really look like crap if we let them! LOL

    Other times, I'll take Tim Payne's advice, like I do in EnvironKits, and use many ray tracing lights in a dome. The magic number used in EnvironKits is 88 lights, which produces nice, soft shadows without having soft shadows turned on, but then the Sun Light in EnvironKits is set to have soft shadows. So when I use my EnvironKits, I open the lights replicator and change the minimum distance from 280 to 980, which changes the number of replicated lights from 88 to 11. Then I turn off soft shadows from the sun. Now if I were to do a shadow test on a sphere with a simple shader, we'd see that it produces somewhat blotchy shadows. But when I'm doing this, I'm mainly doing it on the scenery and to cast shadows from the main subjects onto the scenery. Other than that, I use specific lights (three of them) to illuminate the main subject separately.

    So I go through a whole process to force my scenes to render quickly. It's super easy to create scenes that take a long time to render. it really is. Carrara has some really high-end features, like blurry shadows, sub-surface scattering, reflections that can carry on through many, many, many ray bounces, etc., 

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