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Thread: Changing IoR Radially

  1. #1
    Male Modeler ccclarke's Avatar
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    Changing IoR Radially

    Can one of you nodal experts tell me if it's possible to texture a glass cylinder so the Index of Refraction varies from the center to the outer edges? I'm trying to build a GRIN lens using a source light rather than an animated 2D hack to simulate the rays. The center should have an IoR less than the outside diameter. All of the setting I see, (dielectric material node for instance) use a single IoR value, but I'm sure there must be a way to change it from the center of the cylinder outwards.

    Thanks in advance!

    CCC

  2. #2
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    You might be able to use a Gradient on the cylinder's X Coordinate:

    Click image for larger version. 

Name:	GRINLens_WithDefaultIoR.jpg 
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ID:	147043 Default Index of Refraction on the Dielectric

    Click image for larger version. 

Name:	GRINLens_WithXCoordGradientIoR.jpg 
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ID:	147044 With X-Coordinate Gradient, lower IoR toward edges

    Here's the setup of the attached sample scene / object:

    Click image for larger version. 

Name:	GRINLens_IoRGradientSetup.jpg 
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Size:	877.0 KB 
ID:	147042

    If you truly want it radially, you could use a Distance Vector between the Object Position and the World Position, zeroing out the appropriate axis to make the distance cylindrical.

    mTp

    P.S. Here's the Radial Gradient IoR setup:

    Click image for larger version. 

Name:	GRINLens_RadialGradientSetup.jpg 
Views:	16 
Size:	1.08 MB 
ID:	147046

    and the scene / object is attached.
    Attached Files Attached Files
    Last edited by MonroePoteet; 03-12-2020 at 01:15 PM. Reason: Add GRINLens_RadialGradientIoR scene & setup

  3. #3
    Male Modeler ccclarke's Avatar
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    Thanks MonroePoteet. You rock!! I'll try this out and see if the light beam raytraces realistically to form a realistic output by taking a coherent light source and shaping it into a focal point. (The size and changing IoR of the GRIN lens allows control of the focal plane.) This is simple to do in Zemax/OpticStudio when designing an optical path, but I'm trying to simulate a working engineering model if it can be done within Lightwave for a larger demo that is more visual than technical.

    Again, many thanks! I really appreciate your help.

    CC
    Last edited by ccclarke; 03-12-2020 at 08:05 PM.

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