This is a two part question / curiosity …
I’m trying to understand how the Analyze --> Angle command works to measure the angle between two objects.
How does the command determine whether to return the acute or obtuse angle between objects? I’ve noticed that if the angle is close to 90 deg, the returned value may be the acute angle (x) that is not modeled (ex. the surfaces are obtuse to one another). The correct angle as it sits in space is 180-x.
In the below image the object has a non-orthogonal normal for one surface, and an orthogonal normal for the other. Also, the top edges are orthogonal.
It makes sense why the TwoObjects option produces a different result (54.19) than the same command snapping lines (53.78) at the top of each surface. But I experimented a bit by slicing each surface with a plane perpendicular (extruded along normal) to the large surface. The resulting intersecting lines produce an angle of 54.05. My question is, why wouldn’t this have the same result as the TwoObjects option?
As a disclaimer, these results are well within our fabrication tolerances, and the angle measuring process in Rhino has worked out quite well for us in the past. But since we’re folding metal quite often, we come across these little discrepancies that I’ve become curious about.