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How to animate material based on intersection with another object?

5 REPLIES 5
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Message 1 of 6
nb13ki
335 Views, 5 Replies

How to animate material based on intersection with another object?

Hi I am trying to animate the path of a needle guide (green line) as it covers the blue region of the prostate, first top half then bottom half.

I also tried using a texture object mask, with a plane, but it's too straight, the coverage should be arc like. Using a bend modifier did not help.

I wanted to animate the path covering the top half and the the bottom half. I can do this with a bitmap, but it's very difficult to do and make it look accurate.

The material also has emission, so I want the blue area to emit blue and the green area to emit green. Any suggestions would be greatly appreciated.

Fig 1. Using Plane with Object Texture Map
5958-targ-guide-ant-pos-prostate-moving.jpg


Fig 2. Division is straight rather than curved like actual path

I would like the green area to just cover the upper half5959-targ-guide-ant-pos-perspective.jpg


Fig 3. Plane with Bend modifier shows actual path, division should be curved like this5960-targ-guide-ant-pos-perspective2.jpg

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5 REPLIES 5
Message 2 of 6
lee_griggs
in reply to: nb13ki

Maybe this would be easier using animated booleans to separate the prostate using the green geo? That way you could assign separate shaders to them?

If they were separate objects then maybe the curvature shader could also be useful.

Not sure if that is what you want?

Lee Griggs
Arnold rendering specialist
AUTODESK
Message 3 of 6
nb13ki
in reply to: lee_griggs

Thanks for the response. I'm not sure what you mean. I tried separating the prostate into quadrants using the slice modifier that way I can work with top/ bottom halves, but I still can't figure out how to make the highlight division curved like a cone.

Message 4 of 6
lee_griggs
in reply to: nb13ki

>how to make the highlight division curved like a cone.

I'm not sure what you mean tbh. Is this a modeling or a shading task? If you could share the scene, maybe I could understand better.

Lee Griggs
Arnold rendering specialist
AUTODESK
Message 5 of 6
Anonymous
in reply to: nb13ki

I don't have 3dsmax but it's the same thing

Use state_vector Node with geometric normal
a range Node to animate the cut
rgb_to_float to extract whatever the channel you want to use it as a cut
switch_shader with 02 material ()
map the index with with rgb_to_float
Hope this help
6040-statevector.jpg

Message 6 of 6
lee_griggs
in reply to: Anonymous

Nice. A similar scene file can be found here for MAXtoA.

Lee Griggs
Arnold rendering specialist
AUTODESK

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