Round edges

[rtlprmft]

This is a great tool that I was seeking for several days now!

What I want to do is to create lithophanes that fit into a frame. The frames have round edges. My first idea was to add black corners in the input image, but that comes out very messy.

Is there a chance that you would implement the possibility to define a radius for the edges of the picture itself, for the base and for the frame or give me some advice where to start implementing it? I am not really familiar with the creating of meshes.