Model speckles on override material.

[Steve_Green]

Hi,

I'm bringing in a model into Max from Maya for rendering.

Model was transferred via FBX and contains OpenSubDiv

Model was off so scaled using scene scale by around 100.

I noticed rendering seemed a bit slow, so tried adaptive subdiv just for kicks and noticed speckles all over the object when using override material with a standard VRay material.

Regular adaptive cleans it up, but is pretty slow even on a plain shaded material, so there seems to be something else going on.

I isolated individual parts and it renders properly, but when everything's unhidden the splotches return.

No GI or anything, so it's not that.


At first I thought maybe there was another model with coincident faces, but I can't find it if there are - I can get quite a few bits of the model unhidden then it appears but trying to work out what is causing it is proving tricky.

What's weird is if I assign a regular VRay material to it, it renders fine...


So not sure if it's something to do with the import, the scaling or the override material option itself?

Thanks,

Steve

[Zdravko.Keremidchiev]

Could you please send us the scene to suppport@chaosgroup.com . Make sure to mention this thread in your e-mail.

[Steve_Green]

Hi, thanks - have sent it via wetransfer mentioning this thread.

Regards,

Steve

[Zdravko.Keremidchiev]

Thank you for providing the scene. Apparently this particular scene setup is not good to be used along with Probabilistic lights option. The low Probabilistic lights value and the small scattered lights in the scene causes this noisy effect. Therefore in order to fix it you can either disable Probabilistic lights or set it with a higher value.

[Steve_Green]

Hi,

thanks for taking a look - although I'm confused, there's only one spot in the scene, If you mean the VRaylight material on the windows wouldn't the override (default) material make it just act as a plain model?

Even stranger, I turned it off and on and it seems to work...

Cheers

Steve

[Zdravko.Keremidchiev]

wouldn't the override (default) material make it just act as a plain model?

Actually no, the VRayLightMtl will still emit light when it have Direct illumination enabled.

Even stranger, I turned it off and on and it seems to work...

I can't reproduce that. Do you mean that you disable Probabilistic light, render, then enable it and render again with no noise?

[Steve_Green]

Yep, I just disabled it, rendered, then enabled it and it cleared up the noise.

[Zdravko.Keremidchiev]

That is strange. Could you try to disable, enable the Probabilistic light then save the scene and reopen it. If the noise is still gone, could you please send us the scene like that?

[Steve_Green]

Hi, will do - my machine is tied up at the moment but will give that a go when it's available.

Thanks,

Steve

[Steve_Green]

False alarm I'm afraid, I must have turned off direct illumination in the material.

Cheers

Steve