Now I have attempted assigning a different material to the individual segments, instead of setting their property visible=false. I am assigning material=invisibleWire, a material with visible=false and color=0xFF0000. And this looks like it is obeyed (since these segments are red) - except of course for the fact that the lines are still visible!
let's review: the segments within the mesh objects faithfully respect the material assignment, except for the visible property of the materials. This seems like a bug but I'm not sure. What shall I do... Thanks Matt
