You don't select any feature to rotate, so maybe it depends on the actual work plane (I'm not at the cmm).
In addition, why dont level Yplus on pln_top ? And pln_front rotate z around Y ?
Creating the origin of each axis with planes use centroids of planes to origin. Creating a corner point gives another origin if planes are not perfectly perpendiculars...
If you don't select a feature, and you type in a rotation Offset angle value, PC-DMIS follows the right-hand rule of rotation. PC-DMIS follows the convention to treat both the negative and positive axes as positive. This means PC-DMIS always rotates about the XPLUS, YPLUS, or YPLUS axis. It does this even if you select XMINUS, YMINUS, or ZMINUS. Positive offset angle values go in the positive direction (counter-clockwise), and negative values go in the negative direction (clockwise). The software enables the Rotate to list when you select a feature that controls an axis that matches the vector of the selected feature.
Note: This is a direct copy and paste. I think the second YPLUS listed is a typo and meant to say ZPLUS.
If you rotate to a feature, "about XPLUS/ about XMINUS" are identical, since the feature has its own vector.
So why not eliminate all the "MINUS" axis' altogether?
@CHRIS_C: Checked really quick, it makes no difference. It appears that PC-DMIS does not differentiate between "about XPLUS" and "about XMINUS" either way. (I also tried both remaining combinations with same non-result).
Reminds me of my B180 & B-180 probe angle fiasco. We autocalibrate with parameter sets and have always used 180. Somehow a program got written using -180 and even though they're physically the same angle, PCDmis recognizes them as two separate angles for calibration. So nothing repeated well cause it was using an uncalibrated angle, but visually everything ran just fine. Hard to find that one - sign in such an unexpected place in a 100+ page program.
Shouldn't these alignments (rotated 90 degrees about XPLUS, vs about XMINUS) be completely different?
Yes, they should be different. I am assuming PC-DMIS follows some rules such as ccw=positive for rotation signs so, in that case, rotating by a positive angle around axis <-1,0,0> (XMINUS) should be in the opposite direction as rotating by a positive angle around axis <1,0,0> (XPLUS). This has nothing to do with the workplane or anything else as this is a 3D function.
Right or wrong this quirk will never be fixed. There are too many programs with rotation commands in them that will suddenly break if this is changed. I noticed other quirky commands such as the cross product function so that is not the only one.
