Black Normal or Shadow Artefact Appears on Render

[Caveman]

Hi please help me with this issue. As soon as I turn the shadows on for the lights some jagged segmented black stuff appears in the shadow areas.

Only increasing the Render Level to some insane numbers in Geometry Approx seemed to lessen those uglies.

Please help

[rray]

That's something normal you get in any renderer when using a point light source (non flat quad gets tesselated->one triangle faces the point light source, the other one doesn't). It gets less noticeable the more lights you use (or the smaller the polygons). Only option if you want exactly that kind of lighting then is to use a small area light source.

[Caveman]

Hi rray I think it's more of mental ray's problem with this geometry. In Maya I was able to completely remove these artefacts by applying a Geometry approx but in Softimage it doesn't work. This happens in Max too but can be solved by applying a turbosmooth modifier and setting the render subdivision level to 1 but Softimage needs level 4 and still has it. I have used an Area light too but it doesn't change the result. Both VRay and Arnold has no problem with this geometry. But I can't use them in my projects because I don't own them, they are in the workplace.

I am concerned for this because earlier in a small project I did with Softimage I got these same black uglies popping up all over a specific geometry. And that completely ruined the quality for me.

Now I am starting to understand why people don't like MR. I know almost all the MR settings which are exposed in the Autodesk Suite and still I am unable to solve every new issues that keeps rearing it's ugly head every now and then in MR

[Superpositivo]

In the Light PPG, activate Shadow Map. Then increase the Render Bias to 1 or 2.

It should work instantaneously.

[Caveman]

Hi Superpositivo.

Your workaround is great. But generally I tend to stay away from Shadow Map. Like rray said after adding a few more area lights it has greatly reduced those unwanted black stuffs. Although it has just reduced it, still no way to eliminate it, on the other hand Maya's geometry approx for MR solves it completely.

[Superpositivo]

Actually I used your scene. I activated Shadow Map. and did as I wrote before.. nothing is changed, but the artifacts disappeared. It's not the same for you?

[Superpositivo]

Here it is...

[Caveman]

Actually I used your scene. I activated Shadow Map. and did as I wrote before.. nothing is changed, but the artifacts disappeared. It's not the same for you?

LOL I was editing my post to put it more clearly. It surely works, but I do not like the uniform softness of the shadows in Shadow Map.

Thanks for your input.

Rendered with couple of Area Lights defects still present but imperceptible from a distance but clearly visible when close. This is the same geometry but with normal maps applied (which I was testing). The geometry has a subd level of 1 in the geometry approximation.

[Superpositivo]

So maybe you should post an image of what you achieved that you think you like, but with the artifacts...

Anyway, in the previous image, the light in the scene didn't change. Only the artifacts (well, set higher the material parameter to let the artifacts show more)

[Caveman]

My mistake MR Approximation in Maya doesn't work either. So this is MRay's problem or my Geometry's .