per particle attr with shaders

# 1 17-05-2005 , 08:20 PM

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Join Date: Feb 2003

Location: Los Angeles

Posts: 695

Hey gang. Got a new quandry some of you may have already solved. If so your assisstance would be greatly appreaciated as usual.

I've got a particle system that uses instanced objects. Now each object is similar, but a little different. I've got my MEL scripted so that each one has varied X,Y, & Z scales to help sell the allusion that each particle is a unique object. The last thing I want to do is vary the HSV values of each particle. This is where I'm getting tripped up.

I know that rgbPP is for hardware only. I've been looking into the Particle Age Mapper node, but it seems to be for software particles like blobs, clouds and tubes. Since instanced geometry, uses the color channel of a shader, I need to find a way to connect so random values to the shader. Am I making snese?

Anyone have thoughts on what might work?

Thanks,
-dann

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# 2 17-05-2005 , 11:01 PM

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Join Date: Oct 2002

Location: London, UK

Posts: 2,800

can't you just add a vector attribute to each one that is a random number representing a colour then in the shader make it pick up the value from the object to colour itself? is that a clear explantion? I'm not sure maya can handle that but it might work.... user added image

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# 3 17-05-2005 , 11:23 PM

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Join Date: Feb 2003

Location: Los Angeles

Posts: 695

Well what that would do is apply that number to the shader, but since it's the same shader on all objects the change would be applied to all objects.

What I've decided to do is the following. I've got 12 geom objects that are each a little different. Each has it's own shader so I've added a remapHSV node to each one. Then I added a locater as a control object and scripted some variables to be able to control the amount of HSV variation for each shader.

Example.
remapHsv01.hue[0].hue_FloatValue = (controller.hueVar * 1.0));
remapHsv02.hue[0].hue_FloatValue = (controller.hueVar * 0.5));
remapHsv03.hue[0].hue_FloatValue = (controller.hueVar * 0.1));

Unfortunately, every particle will not be unique, but with 12 variations of the shader and 12 different models it should be convincing enough. Especially once all of motion, lightings, and motion blur are factored in.

If anyone can think of a way to do it right so that every particle gets a unique value, I'd still love to hear how you do it.

Thanks,
-dann

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