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kanooshka
05-11-2009, 11:41 PM
Hey guys,

I'm using maya and mental ray and I was wondering if there is a way to have multi bounced specularity without having reflections enabled. For example an object is sitting on a table with a specular highlight, the highlight does not "reflect" onto the table. Is there a way to do this without enabling reflections on the shader? If reflections are enabled the diffuse is also reflected which is not the look I wish to achieve.

Cheers
Dan

mister3d
05-12-2009, 02:30 PM
I guess no because anyway you have to trace it at least once. But maybe it's possible to write a shader for it.
Why do you need this? For a what particular reason? There are wonderful shortcuts for speeding-up reflections in mental ray up to date. :surprised

kanooshka
05-12-2009, 02:48 PM
I guess the main reason I wanted to do this is so I don't have to use blurry reflections on an object. If I were able to use a specular highlights roughness in a reflected specular highlight, as opposed to raytracing a blurred reflection to get a similar effect, the render times would improve.

mister3d
05-12-2009, 04:26 PM
I guess the main reason I wanted to do this is so I don't have to use blurry reflections on an object. If I were able to use a specular highlights roughness in a reflected specular highlight, as opposed to raytracing a blurred reflection to get a similar effect, the render times would improve.

I think the sacrifice is too big, so you'd better use glossy interpolations and turn off reflectivity (leaving specular only with highlights+FG only). if you need faster reflections, then use the third, the quarter etc of the interpolation grid density. The only problem is if you have specular samples scattered they may look bad blurred. But you can blur mirror-like reflection to get the only sample from the specular.
From my tests the interpolated reflections even work for animations. But if you have some textures with bump it may work.
The last mental ray is so much more friendly and adjustable. :love:

kanooshka
05-12-2009, 04:39 PM
I do like the reflection interpolation the only problem is that the mental ray shaders don't obey the emit specular/emit diffuse light options, at least in maya 2009. Because of this, I tend to stick to the reflection contribution of the native maya shaders, rendered in MR.

lazzhar
05-15-2009, 07:52 PM
... the only problem is that the mental ray shaders don't obey the emit specular/emit diffuse light options, at least in maya 2009. ..
It's fixed in the recent update SP1.

kanooshka
05-15-2009, 08:05 PM
Thank you!

mister3d
05-15-2009, 08:46 PM
You can also set the trace depth of the shader to 1, which will make pretty much what you want I guess. And also play with the "max distance" in the advanced reflection options.

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