3D shape capping

Dec 3, 2012 at 5:52pm

3D shape capping

I was wondering if someone could offer some advice on how to render the intersection between a 3D-polygon (possibly concave) and a plane. That is to say, I want to draw the area of the plane that is inside the polygon in a different color from the area outside.

Help much appreciated!


Dec 4, 2012 at 7:28pm

hey sam.
probably easiest way to do this is with textures.

you can capture the shape to a texture, and use that with something like jit.gl.pix, to determine which color to paint the plane.

– Pasted Max Patch, click to expand. –
Dec 4, 2012 at 7:37pm

if you want to go the geometry route, distance functions might allow you to perform boolean operations.
check out my reply here: http://cycling74.com/forums/topic.php?id=31304

Dec 5, 2012 at 5:31am

Hey Rob,

So unfortunately while what you sent me is pretty cool, it’s not quite what I’m looking for. I was really hoping for something more like a cross section than simply projecting the object down onto a surface.

This thread seems to describe pretty well what I want to do, along with what looks like a solution. http://www.opengl.org/discussion_boards/showthread.php/169569-cap-clipped-complex-geometry

The only downside is that it involves a lot of openGL wizardry that I don’t really know how to approach in Max.

Any thoughts?

Dec 6, 2012 at 9:55pm

ah, yes. significantly more complicated.
i will have to defer to andrew b or wes for this one.
sorry sam!

May 24, 2013 at 8:11pm

Hi Sam,

Did you (or anyone else) get anywhere with this? Very curious to hear what you learned.


You must be logged in to reply to this topic.