Can you measure the volume of a rendered shadow?

I want to know if it is possible to measure the volume of a rendered shadow’s shape. For example, the attached image shows a point light source shining on a square and casting a shadow onto the plane below it. I want to measure the area of that black shadow shape. Any ideas?

Also, this example is a very simplistic shape, not nearly as complex as the shapes I need to calculate this for. So doing something like tracing the shadow outline in a rendered view-port with a poly-line won’t work for my real issue.


Hello - not directly, you’d need to jump through some hoops- for example,

Extrude the border curve of the surface to a point (the light source)
ExtendSrf the individual faces of that object through the plane.
Trim the surfaces with the plane and the shadow casting surface(s)
Join to make a closed object.
That could get complicated pretty quickly, I’d think, if it was not a simple case like you show.
It is probably possible to script this…


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