Blinking specular

[Logitek]

Hello,

I'm trying to render a small animation but I'm facing a "small" problem.

All my specular are blinking, especially at the end of the animation on those springs (see attached file or www.archimed-studio.com/transfert/GratteProblem.mov )

For my settings, I’m using Adaptive DMC (4 and 7… I actually started lower, and raising these number do not change the problem). The DMC Sampler noise Threshold is at 0.001.

IR: High Animation with 25 HSph and 20 Interp. Samples in Multiframe incremental

LC: 1500 (I started at 500 and raising this doesn’t seem to fix the problem either), sample size 0.005. I use Fly-through Mode.

Does this sound familiar to anyone?

Thanks a lot in advance for your replies.

Matthieu DELARUE - ARCHIMED STUDIO

[Logitek]

I've tried calculating the IR first and using "from file" instead of "incremental" (by the way, this is what I should have done from the beginning, the IR is a lot more "stable" trhoughout the animation), but that didn't fix the problem.

I think the problem comes from the fact that the specular if calculated at rendertime, so at each frame, the calculation is slightly different. I think I need to somehow bake the specular into something, kind of like the GI is baked into the IR, but I have no clue on how to do that.

 

any ideas why? not even a small clue? pleeaaaaase!

[gfa2]

Try checking "sub-pixel mapping" and "clamp output" in the Vray color mapping rollout. That will help with aliased speculars.

[Logitek]

thanks a lot Gary!

I don't know why I never used this sub-pixel mapping before! I guess without it checked, raising the DMC samples is quite useless, isn't it?

 

I'll look this option up to see what it exactly does. For now, it fixed my problem, so thanks again!!

[gfa2]

Glad it worked for you.

 

I don't thing you are using this, but just so you know, one downfall to clamping the output is you are chopping off any value greater than 1. So if you are working in a linear 32 bit floating point type of arrangement you are clamping everything at 1. This can mess up compositing if you need your brights beyond 1.

[nelpiper]

One thing that's very important is that WORLD should be used rather than SCREEN for animations in case you're doing that.

[Logitek]

One thing that's very important is that WORLD should be used rather than SCREEN for animations in case you're doing that.

I was wondering about this option and thought I would make sense to use it, but I have no clue about what size I'm supposed to use with WORLD... Should I just leave the default value Vray gives me when I switch to world?

thanks!