Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Fluss on 2017-08-09, 10:44:27
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Since I use corona, i've done interior renders only. I'm starting my first animation, mostly exterior shots. I have taken for granted the use of PT+PT for exteriors and PT+UHD for interiors. But after some tests, i didn't manage to find any case where PT+PT is faster than PT+UHD, even for exteriors (corona 1.6.2). In fact, PT+UHD is tremendously faster (5min vs 20min in my case).
I want to make some greenery animation. Does it suit well with PT+UHD (UHD cache rendered every frame) ? Can't do much test atm (single workstation), i will use an external renderfarm. So if anyone has experience with PT+UHD and moving objects, your feedback could help me a lot.
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Rawa provided me some hints. He rendered his "NyLeve Falls Remake" animation in PT+UHD (UHD every frames) with UHD precision @2.0 . So I guess it work well with animated foliage ? (Only branches are moving in rawa's animation).
Increasing UHD precision have a hudge impact on GI calculation. I assume he did this because he had some flickering issues with default precision. Anyway, PT+UHD is still faster -> now PT+UHD = 11min with precision @2.0 vs PT+PT = 20min.
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Generally it is true that PT+UHD should be used for interiors, and PT+PT for exteriors.
More precisely, PT+UHD should be used for scenes where GI is prominent, and PT+PT should be used for scenes where direct lighting is dominant.
If you have an exterior scene with some kind of pavilion, or other roofed area, then PT+UHD would make perfect sense.
Why PT+UHD may not be recommended for exteriors? It's simple:
-With PT+PT the rendering time of each frames is just the actual rendering time (plus some geometry pre-processing like displacement, but let's forget about it)
-With PT+UHD it's rendering time plus UHD precalculation time, and this time can also be very long, especially in large exteriors with lots of grass and trees
So when using PT+UHD in exteriors the total time (rendering+precalculation) may be often much longer than rendering time alone when using PT+PT.
If UHD Cache is calculated reasonably fast for you in an exterior scene - it's perfectly fine to use it.
Another thing is fly-through vs moving objects. I think it's explained well here: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515648
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Thx maru, that's the first thing i've read. I have not set the greenery yet so the conclusion might change in the future. I'll have to ponderate this once everything done. Just wanted some user feedback to be sure where to go.
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Hi Maru,
Things in Corona changed(We can just choose 1 GI solver now which is different), so what will be the best way now for exteriors?
I have a scene that keeps flickering, I've increased the passes to 150 and precision to 2, bt still happens, but now my render time per frame is about an HOUR! yep....:O
Scene is really heavy with foliage, but to increase it even more will take more time per frame...
Any suggestions?
Cheers
Jireh3D
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Things in Corona changed(We can just choose 1 GI solver now which is different), so what will be the best way now for exteriors?
Sorry, but I don't understand. You mean that you can set primary solver to PT, and secondary to none? It was always possible to do it, but it does not make sense in any realistic production scene. This is only useful for "faking" stuff, or for rendering something a bit faster than usually. Just don't do it. :)
I have a scene that keeps flickering, I've increased the passes to 150 and precision to 2, bt still happens, but now my render time per frame is about an HOUR! yep....:O
What kind of flickering is that? Could you post an example? You can send it to our uploader where it will be kept private: https://corona-renderer.com/upload
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There isnt an option for 1st & 2ndary anymore like before...(image attached for you) - I'm using the newest Beta 1 for Cinema 4D here....
Here's the links Maru:
https://www.dropbox.com/s/nayy1p1bz9q08oc/test%20b%20-%20exterior.mov?dl=0
and
https://www.dropbox.com/s/9gyr8d0h89otpuh/test%20a%20-%20interior.mov?dl=0
Thx so much :)
Jireh3D
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In your tree test, it seems an AA problem.
In exterior with a lot of trees, you must to use only PT+PT with low GIvsAA (more passes in the same amount of time).
In this way, you will have more AA Samples, because you don't need a lot of GI samples.
In the fly-through interior, you have to use PT+UHD, but you have to pre-caluclate UHD with "Try to Load + append" option.
If you will use "calculate from scratch", the UHD will change, frame by frame, the sampling and you could have flickering.
Obviously, in interior scenes, GIvsAA should be 10-20, depending the complexity of the scene (a lot of GI or a lot of DOF)
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thanks cecofuli - but corona changed as you can only select PT or UHD... Cant select both anymore. (Previous picture i attached)
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The flickering in your animation is most probably AA as Cecofuli noted. One part of it could be also reflective surfaces catching the reflection of the sun or other bright parts of the image. I would suggest lowering GIvsAA to 8, and allowing more passes to render, plus there are some possible solutions listed here: https://coronarenderer.freshdesk.com/support/solutions/articles/5000529356
Also, enabling bloom and glare and sharpen+blur should help with this.
thanks cecofuli - but corona changed as you can only select PT or UHD... Cant select both anymore. (Previous picture i attached)
PT means PT+PT
UHD cache means PT+UHD
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And in your screen capture, "Full (multiple bounces)" in the GI mode is PT.
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ok thx guys! let me try it.
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Ok I just loaded the short animation up on the private uploader.
My settings used: 150 passes,
GI/AA balance 8, samples multiplier 2
Set on animation flicker free - precision 1
Image filter - Blackmann-Harris px 1.5, Highlight clamping 0
Denoise, 0.6, radius 0.6
Sharpening & blur: 1; 0.3 & Blur radius 1.8
Still very flickery and takes about half an hour per frame
Scene is 8million poly's done with render instances
Many thanks
Jireh3D
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Ok I just loaded the short animation up on the private uploader.
My settings used: 150 passes,
GI/AA balance 8, samples multiplier 2
Set on animation flicker free - precision 1
Image filter - Blackmann-Harris px 1.5, Highlight clamping 0
Denoise, 0.6, radius 0.6
Still very flickery and takes about half an hour per frame
Do you mean the flickering on the plants around the house? Anything else?
Please try this:
-reset all settings to defaults (I could not find the button to do it in C4D, but GIvsAA 16, LSM 2, MSI 20, filter: tent, filter width: 2)
-disable denoising
-then set GIvsAA back to 8
-render to at least 150 passes, and if possible, then more (200?)
-if that does not help, then I am afraid the best solution would be rendering in higher resolution
-if you would decide to render in higher resolution, then you could probably revert GIvsAA back to 16 as you should have better AA quality then, so you could sacrifice some computing power to faster GI calculations
The reason why the plants are flickering is because their branches are very thin, like one pixel or less. This requires a lot of AA to render flicker-free.
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Yep exactly that....
Sure will do it & try it Maru! Thank you!
The plants are also animated, so a slight wind blowing...
(I had the sharpening & blur setting on in the sample i sent) Sharpening & blur: 1; 0.3 & Blur radius 1.8
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Also enabling blur and sharpen should help. I am actually testing that right now and will post results soon. :)
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So the conclusion is that lower givsaa, more passes, and blur/sharpen help with this.
I am attaching my tests.
def - default settings
32pass - number of passes per frame
gi - gi vs aa value
blur - sharpen/blur enabled in vfb
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My test, with default parameters...
http://www.francescolegrenzi.com/Temp/Corona/0224_CoronaProxy_Tree.mov
http://www.francescolegrenzi.com/Temp/Corona/0225_CoronaProxy_Forest.mov
Ok, I have not so strong hightlights as in your test, but, I don' t see any problems.
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So the conclusion is that lower givsaa, more passes, and blur/sharpen help with this.
I am attaching my tests.
def - default settings
32pass - number of passes per frame
gi - gi vs aa value
blur - sharpen/blur enabled in vfb
ok what is the values you use for sharpening & blurring? also default?
I've just done 1 render with 200 passes and it is still grainy, but takes an hour a frame ...:(
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My test, with default parameters...
How many passes? Also, I think the biggest issue is when there are objects smaller than 1 px (like small branches) and there is subtle movement.
ok what is the values you use for sharpening & blurring? also default?
I've just done 1 render with 200 passes and it is still grainy, but takes an hour a frame ...:(
For sharpen/blur I used the default values.
You should get roughly the same render time with:
100 passes and gi vs aa set to 16
200 passes and gi vs aa set to 8
400 passes and gi vs aa set to 4
So if you set passes and gi vs aa value proportionally, then the render times should not rise.
You can also try setting light samples multiplier to 1. It should not affect render quality in your case, and will additionally cut render times.
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Hi Maru,
I rendered it as above like you mentioned, but no luck...
- default corona settings
- 400 passes per frame and gi vs aa set to 4
- no denoising
- sharpening & blur on, but I've increased the blur to 1.8 so i have more blur
So last option i have is to render the animation at bigger resolution, but it means longer render times & editing them smaller afterwards again?
I'll try to send you a scene with my plants & settings if that will help...
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So last option i have is to render the animation at bigger resolution, but it means longer render times & editing them smaller afterwards again?
I'll try to send you a scene with my plants & settings if that will help...
Yes, unfortunately rendering in higher resolution usually means longer render times. But it's strange that it seems to be so problematic to remove this kind of flickering. I wonder how it would work in other renderers
You are welcome to send the scene using https://corona-renderer.com/upload
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thx Maru! I did send the scene this morning ;) Just check it your side again :)