Revision history [back]

This is a bit weird. (Not the blue, that shouldn't have been green in the first place, though I can confirm that with older Sage versions it is.)

The Schlegel projection stuff is still technically working, or at least something is happening:

sage: from sage.geometry.polyhedron.plot import Projection
sage: P = Projection(poly)
sage: P.schlegel([2,3,5,7]).coordinates_of([1])
[(0.0538250745189, 0.279021759081, 0.729415128204)]
sage: P.schlegel([2,5,11,17]).coordinates_of([1])
[(-0.209018866441, 0.144793545531, 0.852418369476)]

And luckily, there is a workaround.

sage: P.schlegel([2,5,11,17]).show()

sage: P.schlegel([2,3,5,7]).show()  # different!

But why the renderings directly from projection_direction are not different I can't say. To be fair, I don't see any difference in older (green) versions either, but I'm not that into polytopes or their projections myself so it could be inexperience. I'm putting some comments on some possible tickets that might have changed this in the hopes of getting you a better answer than this, though.