C4D | Multishader and UVW randomizer changes on each frame

[Lebenzet]

Hi ! (apology for my approximative english)

I've an issue with Multishader and UVW randomizer (I'm using C4D 2023 and Corona 9) when making an animation :
Obviously, on each frame Corona changes the seed of the UVW randomizer and the multishader.
On my exemple, multi shader is used to bring variations on the tree's leaves (one material for the leave using multishader to brig variations)  and the uvw randomizer is used to enhance the wood apparence.

It works great on a still image. But it is catastrophic on an animation.

I've uploaded the first three frames and you can see that on each frame, the leaves change their apparence and the texture of the wood is "displaced / moved".
The result is not exploitable.
I've seen that old topics are talking about this issue. I'm wondering if any solution has been provided.
It's really a pity if we can't use these great features when making animation.
Thanks.

[Beanzvision]

Hi there, what version of Corona are you using? I tried to recreate this but couldn't get it to change from frame to frame. I was testing it with the V10 daily build which I will link below. Can you share a down-scaled version of your scene or the material setup for the leaves?



V10 daily: https://drive.google.com/drive/folders/1cMHzUt4QXW_KvapPe6Ar1k5e0SUKE8Ei

[TomG]

Are the trees in your scene animated in some way? Looks like they are, and this could cause the geometry to be different each frame and therefore these randomizations would change each frame. Let us know about those trees, where you bought them, what the animation format is, etc.

[Lebenzet]

Hi ! Thank you for your quick answer.

- I'm using Corona 9 with C4D 2023 and MacOS.
I gonna try with Corona 10.

Yes : the trees are animated (wind effect to move). I can't make a test removing the wind effect to see if the problem remains.
But the wood on the building which is using a UVW randomizer is not animated.

I'm going to test with Corona 10, without the wind. If the problem remains, I'll prepare the a light version of file for you (after removing all unnecessary things.

[Beanzvision]

Hi, okay, great. I hope the daily helps, if not, we will ;)

[Cinemike]

Is, in any way, the number of objects in the scene changing? Raindrops from a cloner, grass count due to a camera frustum, something else?

[Lebenzet]

Hi everybody !
Thanks for for help !

I've done my tests :
1• I deactivate all animations except the camera
2• I remove the flyings leaves (particles)

and now it works ! (Ive upload 3 frames)

Is, in any way, the number of objects in the scene changing? Raindrops from a cloner, grass count due to a camera frustum, something else?

Cinemike, you have to be right. I had in my scene a grass count dur to my camera and particles which generate flying dead leaves. I removed them in my last test.
I'm going to do some more tests activating one thing after another... Do you have any explication or advice ?

Thanks

[Lebenzet]

Hi again !
I've done all my tests and I can confirm that Cinemike was right :
The problem occurs when :

• I have camera clipping on my Corona scatters (easy so solve... just deactivate them)
• I add a particle emitter (used to have dead leaves flying before the camera)... It's unfortunate that I can't use this.

...even if the scattered items and the objects in the particle emitter don't use these materials with UVW randomizer or/and multishaders.

In conclusion : the number of objects in the scene has to constant during all the animation. As you can understand in this case, it is a limitation.
I hope this can be fixed in the next versions.

However, I precise that it is possible to animate the objects... In this case the trees and the shrubs.

Thanks again for your help.

[Cinemike]

My personal advice: Don't use the Corona shaders in this particular case.
Use the native variation shader instead and in there the Object Variation method "Object name", not the default "Objects" and see if that helps. The variation shader also has a built-in UV randomizer as a bonus.
As for the native Corona shader: hope for the best and wish for the "Object name" method to be added.

I hope this helps, curious if it cured your issue.

PS
Always put the object number changing objects deep to the bottom of the hierarchy in the Objects Manager.