Reflection problems

[mad187]

Hello everyone,

I have been facing this issue. I've isolated it down to a single area light. So long as it glances around the surface. This happens.


I've gone through all the settings, and I am using a linear workflow.
The below did not help -
- increasing sample counts on lights subdiv value does not work
- light cut off threshold does not work
- not caused by rec tex
- not caused by rec tex resolution
- Problem isolated to reflection specifically

What is causing this? Any ideas? Thank you.

[mad187]

I've placed a simple sphere in the same location and it has the same issue. I applied a standard shader and also tinkered with the normals.

Could it be that somehow at a glancing angle and linear workflow. This will show up? It is weird that i've never encountered it before.

[Dariusz Makowski (Dadal)]

Is glossy set to something like 0.5 ? If so then that is perfectly normal and sadly unfixable as far as I remember - even tho I did see renders that deal very well with it and you don't notice it. You just need higher subdivision to make it less apparent.

[mad187]

Glossiness is at 0.550. Thing is I don't remember facing this issue before and (after seeing your work which is beautiful btw), I think you'll know as photographers, we always add that very nice rim light which is harsh but skims across the surface. I haven't faced this issue doing this before till now.

I've tried a standard vray material and the problem still happens.

I am thinking the model came through max and could somehow be screwing up the scene when i open in maya. Any ideas? You reckon that is possible?

Thanks for the feedback btw.

[Dariusz Makowski (Dadal)]

Make a sphere in your scene and you will see that it will have the same problem. As a work around for rim lights you could apply a ExtraTex fallof map or in Maya gradient with facing normal's node to produce rim reflection/light that will be smooth with no errors. But nope having glossy reflection at 0.5 and so on will always produce that kind of errors. Try mental ray you will get similar result. There is only one other engine that I know that don't have that issues but overall its pretty normal at low res geometry.

[griml0ck]

Try subdividing the geometry, should give you smoother result. I've had this problem also with geo being too low res. Add more subdivs seems to fix it.

J

[mad187]

The funny thing is that my friend using 3Dmax didn't face the issue.

This is a CAD file so I can't smooth it unfortunately. Hidden behind that is a low res poly model, even when smoothed once, the problem is visible but obviously due to topology...different faceting of the faces. But the issues are there.

And a simple sphere with mildy low resolution doesn't display this problem in mental ray as well as software. It seems to be a vray glancing light angle issue?

[Svetlozar Draganov]

What BRDF type you are using for the material?

Blinn and Ward types usually produce such issues, Phong should produce the cleanest result.
Try to switch BRDF types and let us know if there is any improvement.

Can you also attach the scene for investigation?

[Dankfx]

Try subdividing the geometry, should give you smoother result. I've had this problem also with geo being too low res. Add more subdivs seems to fix it.

J

The funny thing is that my friend using 3Dmax didn't face the issue.

This is a CAD file so I can't smooth it unfortunately. Hidden behind that is a low res poly model, even when smoothed once, the problem is visible but obviously due to topology...different faceting of the faces. But the issues are there.

And a simple sphere with mildy low resolution doesn't display this problem in mental ray as well as software. It seems to be a vray glancing light angle issue?

its a geo issue in maya, you might have to rebuild. But first Try to unlock the normals, and then average the normals. I had this happen a couple weeks ago. Once you unlock and average you can try and smooth again. Might work after.