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Some JS allow "U" keypress

Posted: Sat Jan 31, 2009 6:23 pm
by polymorphic
I don't see this as a problem but some of the Johnson solids allow "Create Unform Polychoron from 3D vertex figure". Not a lot of them but a few. They result in something that is not closed, but creates some very interesting results anyway.

J1 - no complaints but says it has 8 cells but I only see 7. Dual doesn't work.


Posted: Sun Feb 22, 2009 1:10 pm
by robertw
It's a pretty advanced feature and applying it to shapes at random will not find many hits. The first criteria that must be met is that a 3D vertex figure for a uniform polytope must have a circumsphere. Otherwise it will fail straight away. Each face of the 3D "verf" (vertex figure) will represent that 2D verf of one of the 3D cells. But for the model to close up is not foreseeable so if not ruled out straight way the software will go ahead and try to create the model. Unlike in 3D, Stella4D will allow incomplete, ie unclosed, 4D models. This is the equivalent of an edge with only one face in 3D. But if unclosed, creating the dual is not possible, as you've found.