what's happend with shadows?

Started by hirosima, February 17, 2013, 09:39:40 AM

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hirosima

Hello! Need some help with animation render setup's :'(
rendered 3 GI files (3-3-16, Supersemple on, prepass padding 0.25), blend mode interpolate, number of files 3 for 80 frames animation
filter mithcel, detail blending 1
detail in camera, both padding 0.25
animation check button was pressed

so what i have... first 10 frames is ok, but after i got some hard black shadows  :o **.obj in scene was tested in another animation with same settings, when camera moving "forward", not from side. so i have problem only in side camera
and that shadow harder at 50 frame,60.. can some one explain what i do wrong?
Thx for help

Tangled-Universe

Hi Sasha,

It's difficult to understand, for me, what you did.

To me it seems you have only cached 3 GI files for 80 frames, which I think is not a very good approach.
But did you write out 3 caches for the entire 80 frames or 3 caches at default settings?
The latter would mean you'd have GI caches of frame 1, 6 and 11.
If it's the latter then it makes sense you get these results.
If it's the first then it's difficult to say, other than that you're using this feature in a way which I think is not suitable.
Oshyan might help you out here with outlining the minimum of caches you need for 80 frames.

My idea is that your shadows are a result of shadows from previous frames (shadows from cache 2 blended with frame 70 will be at least ~20 frames off).
By default you cache out every 5th frame, so for 80 frames of animation you would end up with about 15 caches. Instead of 3.

So what happens if you cache every 5th frame for GI and then blend 5 caches for each frame when rendering?

For GI settings I wouldn't use GI relative detail @ 3 by the way. Faster and equally good is GI relative detail @ 2 and use sample quality of 6 or 8.
The reason for this is that its better to take fewer samples (relative detail), but calculate them multiple times (sample quality).
You have less dense GI coverage but every calculated GI sample is more accurate.
Blended with other frames it should give better results.

hirosima

Yes, you are right. I just use 3 gi cached files for 80 frames animation. Gi cache setup: relative detail 3, sample quality 3, blur radius 16. And i blend them by 3 files for all my sequence
I try to render more gi cahce files, but.. in previous animation test from this scene, render setup's was same(+/-), camera translated forward, and i don't got that shadows :'(

cyphyr

Three cached files over 80 frames is very low. My defaults setup for animation is one GI cache every 10 frames and a blend of 5. However if the lighting changes abruptly (in under 10 frames) then I would render more frequent GI cache files (maybe every 5 or 7 frames).

Quote from: Tangled-Universe on February 17, 2013, 10:25:02 AM
For GI settings I wouldn't use GI relative detail @ 3 by the way. Faster and equally good is GI relative detail @ 2 and use sample quality of 6 or 8.
The reason for this is that its better to take fewer samples (relative detail), but calculate them multiple times (sample quality).
You have less dense GI coverage but every calculated GI sample is more accurate.
Blended with other frames it should give better results.
Agreed :)

Richard
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Oshyan

A small number of GI cache files can work for larger numbers of frames, but the situations where that works are much less common. If you have very low camera movement, and no dramatic lighting changes, it my work out though. Without knowing more about what your scene is doing, it's hard to say what the problem is. I would start by eliminating GI as a potential cause altogether, disable GI, use fill lights if necessary, and render some test frames.

- Oshyan

hirosima

thnx people! i will try to render sequence with more gi cache files and post result. but i have 1 more question about "Gi prepass padding" in GI render settings, and the same "GI prepass padding in advanced tab, what they differ?

Oshyan

They are the same setting. You can see this if you change one, it will affect the other. This UI configuration may change in the future, the GI settings were mostly moved into a separate node recently, but it's probably left this way now partly to keep the "Prepass padding" options together.

Note that if you are not clear on what the prepass padding does, and you haven't confirmed it is necessary to use it in your scene, we don't recommend it as it increases render time. It is of course quite necessary and useful in some circumstances. There is a bit more info at the bottom of this page: http://www.planetside.co.uk/wiki/index.php?title=Terragen_2_Global_Illumination (which is a great reference overall, definitely read through it if you haven't already)

- Oshyan