[hatts]

I recently rendered 300 frames of a simple turntable animation, as a network render. The render pass went fine. It is clipped via its alpha.

I then rendered a separate full render pass just for the floor shadow, with the main object hidden to cam. Each individual frame looks great but in AE, the floor shadow slightly flickers as it animates. I know that each frame got to the same SL, so shouldn't this be impossible? Should I have given each node the same seed? Never had this problem before.

Shadow flickering...I'm getting horrific flashbacks of lesser renderers....

[eric nixon]

Yes, use same seed, I think thats the problem. Otherwise post some pics, it may help diagnosis.

[Mihai]

Post some frames if you can, seed number should not affect the lighting if they rendered to the same SL.

[bograt]

I'm getting horrific flashbacks of lesser renderers....

Eurgh! I have never looked back!

[hatts]

Here is the full output.

[Mihai]

Are you sure it's not something in the scene that's influencing the shadow pass? Caustics, reflected or refracted....

[Fernando Tella]

Could it be some problem when encoding the video file? It doesn't look like it could be produced by Maxwell noise.

[eric nixon]

Hatts, if compression is a possible culprit, you can check by loading the original frames into 'Framanip Pro', Its free..

[hatts]

Eric, great suggestion re: Framanip. Really useful tool, with a low bullshit-quotient.

Playback in Framanip showed flickering too. Re-rendered the whole job with a forced -idcpu and it fixed the flickering.

This is troubling to me...something doesn't make sense about flickering shadows generated by unbiased rendering across four (identically configured) machines, with each frame governed by SL.

For the sake of minimizing risk, I have no choice but to -idcpu every time now. Grumble...

[Mihai]

Could you send me the original files of this scene? What SL did they render to? Maybe this is the cause.....a too low SL will show different noise distribution and it will contribute if the noise is still prominent.

[hatts]

Ok, indeed they only rendered to SL 13. I suppose I misunderstood the role of noise with regard to shadow uniformity.

Sorry I can't send the files. I'll just chalk this up as a learning experience and go with a uniform noise seed for any low-SL animation renders.

Thanks for the input folks

[Mihai]

Just be aware in this case you can't do a coop animation render, since the starting seed nr is the same, it won't be able to merge them. Doing a distributed network render is ofcourse ok since no merging takes place - each frame is rendered on a separate machine.