Introduction to Maya - Rendering in Arnold
This course will look at the fundamentals of rendering in Arnold. We'll go through the different light types available, cameras, shaders, Arnold's render settings and finally how to split an image into render passes (AOV's), before we then reassemble it i
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1
15-12-2011
, 03:02 AM
Registered User
Join Date: Dec 2011
Join Date: Dec 2011
Posts: 3
:help: Problem with varying refractive index using Expression Editor
I'm trying to generate a bunch of images with caustic effect, with the glass object has different index of refractions between the images. I'm using Maya 2010, render using mental ray,
So, I tried with the Expression editor, at first I tried modifying the miRefractiveIndex with the expression (yes, I already used Window -> General Editor -> Channel Control to make miRefractiveIndex keyable and unlocked. Evaluation is Always).:
pasted__phong1.miRefractiveIndex = 1.5 + (frame-1) * 0.1
When I clicked around the frame sliders (on the bottom of the screen), I notice the Refracted Index in the Attribute Editor (of pasted__phonge1) did get updated (the box became violet color). However, when I used batch render to render frames 1-3 the caustics didn't change.
Afterward, I found attribute pasted__phong1.refractiveIndex, and did the same thing (that means, I used same expression for both .refractiveIndex and .miRefractiveIndex, also made it keyable and unlocked). Then, after I rendered the frames, the caustics were different, so it worked.
But now, I tried to write my own MEL procedure in the external .mel file, containing a function that returns index of refraction given the current frame number, and I called the procedure from Expression Editor, so now becomes :
pasted__phong1.refractiveIndex = myProc(frame)
and
pasted__phong1.miRefractiveIndex = myProc(frame)
with the MEL script :
proc float myProc(int $frame)
{
return 1.5 + ($frame-1.0) * 0.2;
};
When I clicked around the frame sliders, I noticed the Refractive Index in the Attribute Editor of pasted__photon1 did change by 0.2.
And then..I rendered the frames again, but the caustics were stationary, and the caustics were as if the index of refraction was 0.0, they didn't change at all !
Any solution for this possible bug ?
Many Thanks.
#
2
15-12-2011
, 03:28 AM
Technical Director
Join Date: Feb 2004
Join Date: Feb 2004
Posts: 2,988
The problem might be that you're defining your function as a proc, and not a global proc. You should also give it a more descriptive name incase there are naming conflicts.
Imagination is more important than knowledge.
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3
15-12-2011
, 03:43 AM
Registered User
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Join Date: Dec 2011
Posts: 3
yeah, also not working after I set it to global proc. About the name of the procedure, it's something else, not 'myProc' as written here.
Thanks
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4
15-12-2011
, 04:01 AM
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5
15-12-2011
, 04:12 AM
Technical Director
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Join Date: Feb 2004
Posts: 2,988
Imagination is more important than knowledge.
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