View Full Version : 2011 - dark edges around fluids in render

04 April 2010, 11:24 AM

having "use real lights" turned off , all my fluid renderings have a dark, semi transparent edge around the main fluid body. It is completely irrelevant how I setup the light direction (this is interpreted correctly for the shadows in the main fluid body), this dark edge won't go away. I tried differnet setups in different scenes- all the time there are these dark edges.

When I am lighting the fluid with real lights, that boosts up rendertimes to indefensible values, so I can't use it. I have never watched a similar behaviour in previous versions of Maya, so this might be a bug in 2011.

Do you have made any similar expereineces ?

04 April 2010, 04:00 PM
any chance of posting a few renders to show what you mean a bit better?

04 April 2010, 02:04 PM
Here you are...look at those very dark edges surrounding the fluid. No matter how I set the light, these edges don't go away. Real Lighting is not an option as this consumes way too much rendertime.

04 April 2010, 02:18 PM
Taking a stab here, but I think it is your opacity settings and not your lighting. Try making your opacity graph tighter, move the keys closer or move the first key away from the beginning. Also how are you coloring it?

04 April 2010, 04:04 PM
If you are using surfaceRender with softSurface then going to volume render would get rid of the artifact. (or changing the surface threshold might help)

If not then perhaps you have a spike in your opacity graph... make the graph smoother.


04 April 2010, 04:37 PM
Is that extreme big scale?
if your fluid is very very large, it will have this kind of dark edge in previous maya...
but I am not sure in maya2011.

04 April 2010, 08:36 PM
Is that in your compositing package? Because if it is then thats a premultiply effect on the alpha which is unavoidable because if you take premult off you get a hard unnatural edge.

04 April 2010, 03:00 PM
It is a volume render and the image is not taken out of the compositing software (I already had that "premuliplication " idea) The szene size isn't large, either. The opacity graph isn't looking strange, either. My colleague had the same problem in a maya 2011 fluid in a completely different scene. When rendering with real lights, this was gone.

We were both rendering with mental ray.

I guess it's some interpolation problem with the "fluid light"/self shadowing.

04 April 2010, 05:13 PM
For now if you are using autoResize avoid using ambientDiffusion or the internal light. (keep real lights on). There is a bug currently where the bounds do not properly match up for the internal lighting.


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04 April 2010, 05:13 PM
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