Some edges are colored incorrectly

[jdan]

If you look at the drawing on the project page closely, you'll see the following:

There's a small "hairline" crack in the shape - essentially a discolored edge. This occurs when a portion of a hidden face creeps up. Might be due to floating point coordinates.

[rcmaniac25]

If you make a rotating light, you will find a fair number of extra ones

[ooflorent]

Might be due to floating point coordinates.

I tried to use plain integers but it didn't solve the issue.
I think this is related to #25.

[rcmaniac25]

I have a feeling it has to do with antialiasing.

Draw path, edges are antialiased (I think), draw path next to prior path, edges are antialiased.

Multiple antialiased objects work well together within 3D, as they are all antialiased together. But when drawn one at a time, their edges don't line up.

I could be wrong, I'm just guessing.

[FabrizioC]

@ooflorent nope, you can try but the edges still persists.
The "pixel iso angle" is useful to mix calculated objects with "iso pictures" could be overlapped.

[Mysterix]

Is it really a bug ? After all, what is the color of an edge ? Which of the faces give it its color ?

A partial solution would be to do not display faces that are completely hidden (doable with path ordering (see the other topic)). This does not cover all possible cases, but among other cases it covers the one shown here.
A better solution would have a look at the neighborhood of the edge and consider faces parts that are actually displayed, seems tricky...