(2018-01-14, 22:51)Joshua Delahunty Wrote: I would argue the top would be for *intuitiveness* (rather than uniformity), since the triangle formed by CYLINDRICAL is orthogonal to the triangle defined for PLANAR (and my original reasoning was, put P3 at the base so that the part designer could try to remember that the triangle for PLANAR was wider at top than at bottom, and the plane of the triangle faces the viewer, whereas the CYLINDRICAL had the wider part at the bottom, and was "viewed" edge-on (also in PLANAR P3 defines an endpoint, while in CYLINDRICAL it defines a midpoint). I was specifically thinking that making them as different as possible in all ways was better than having things in common.
I'm not arguing it should not change (as intuitiveness is obviously subjective), I am saying that I don't personally feel that P3 at "top" is uniform with how PLANAR is defined. I'd be happy with P3 in either location, and if more people (so far, 2 to my 1) felt it makes more sense in the top position, that's far more important than my initial intention (putting it at the bottom).
Actually I'm thinking to support both as p3 is really only needed to determine the base direction (or facing direction).
You can calculate that direction using p3 at any place by using it to find the perpendicular vector to the p1 p2 direction.