what are degenerated edges and where do they come from?

[smason]

SALOME's shape gluer code has various branches that are never tested because they are behind if(BRep_Tool::Degenerated(edge)) tests that never come up true. The docs aren't particularly here, currently documenting this function as:

Returns True if the edge is degenerated.

Would be good to figure out how to generate a geometry that has solids containing degenerated edges and know what the "right thing" to do when gluing shapes in the presence of them.

[smason]

The step format uses the term "degenerate" in reference to pcurves, saying:

A Degenerate_pcurve is a type of Point that is defined as a parameter space curve, but in three-dimensional model space it collapses to a single point. It is thus a subtype of Point, not of Curve.

which would make sense to ignore for edge operations, as what's interesting is the point along this curve, not the curve itself.

Not sure if they're talking about the same thing though!