View Full Version : Issues rendering scene with MR (shadows)

07 July 2011, 02:42 PM
I have a scene with a bunch of cached nCloth simulations where each object splits into tons of pieces (its faces), and I'm not able to get mental ray's shadows to work correctly.

I first noticed something wrong when using MR's physical sun & sky (which is what i would like to eventually render with). The shadows looked good in the beginning of the scene, but then some weird artifacts started to occur (see attachment).

So I tried rendering with a single directional light with ray-traced shadows, and was still getting incorrect shadows. The best example I came up with was to render a frame with only one of my objects visible, and then again with all objects visible (second attachment). When I did this, I saw the proof that something was wrong, because shadows that used to exist, being cast from just one object, suddenly disappeared after adding more objects!

I've played with all the quality settings I could find related to shadows in mental ray, but i'm really no rendering expert, and have no idea how to fix this. Anyone have any ideas?

07 July 2011, 09:13 PM
Been searching all day and still haven't found anything about this.

Turns out that all the geometry and shadows can be raytraced fine in Maya Software - but not Mental Ray...? (even with only one object visible, some pieces didn't show up.

I'm at a loss... are there any good free renderers for Maya 2009 that could do FG-quality lighting? I don't think I would be able to get a good looking render with just Maya Software... Any idea what might be causing this?

07 July 2011, 01:35 AM
What's your shadow ray depth limit set to?

07 July 2011, 05:35 PM
I think I may have figured it out. It seems like the errors are connected to having an object with faces spread extremely far apart. For example, some of the shards were flung thousands of units away, when the object itself before shattering was only about 20 units long. I'm re-caching objects now while containing the pieces from going too far, and i'll see if it indeed fixes it.

The anti-aliasing settings also had an effect up to a quality of 1min / 3max.

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07 July 2011, 05:35 PM
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