I want to simulate caustics generated by free form lens using Blender and Lux Core Render as a geometric optical simulator. I know how to create height field surface from a gray scale image using displacement modifier. But what I need is the one with volume, cube-like mesh solid object with arbitrarily height distribution on the top face and flat plane on bottom face. Could please anyone show me how to do it ?

Thank you for your cooperation.


You can still use the displace modifier for this, but with a vertex group to limit the influence to one face of your object.

  1. Select the top face of a cube/suitable volume.
  2. Create a vertex group in Properties > Object Data > Vertex Groups.
  3. Assign the selection to the vertex group.

    enter image description here

  4. Then specify that vertex group in your displacement modifier:

    enter image description here

  • $\begingroup$ I could what I want to do following your method ! $\endgroup$ – Kallabee Mar 13 '19 at 5:56
  • $\begingroup$ I very thank your fast and kind answer with pictures :-) $\endgroup$ – Kallabee Mar 13 '19 at 5:58

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