Wish: "Set CPlane to object" to work with surface control points and surface edges

I think that Rhino would benefit if there was a way to set a custom CPlane with the “Set CPlane to object” command (’_CPlane _Object) via 3 or more selected surface points or a surface edge.

That could be useful for situations where a CPlane must be set to the relative end of a pipe that does not have a perfect G1 radius or another object with variable shape. Currently, to do that, the user is forced to draw a polyline across all control points there (imagine if they are tens or hundreds!) before he or she is able to use the “Set CPlane to object” command.
When the Gumball is set to “Align to object”, and then selecting the 8 control points at the end of a pipe that’s inclined (not vertical and not horizontal), the Gumball refuses to take the common orientation of the control points as a reference for its own orientation and remains vertical.

Also, by allowing “Set CPlane to object” to work on surface edges, users will be able to set a CPlane in a more intuitive way. For example, if I apply “Set CPlane to object” to the end of a pipe, Rhino will not position the CPlane relative to its circle shape at the edge I just clicked. Instead, it will set the CPlane at the middle of the pipe far away from the edge, and perpendicular to the intended plane. That’s counter-intuitive.
It could be avoided by duplicating of the edge and then running the “Set CPlane to object” command, though.

Hello - I suppose the idea is to use a best fit plane through more than three points, correct? The long way is to Divide a curve, use PlaneThroughPt on the result and then Cplane > Object on that - it could certainly be bundled but for curves you would need to ask for a sample count. It works (as a two step operation ) with selected points now.

! _PlaneThroughPt _Pause _SelLast _CPlane _Object _Undo

for an edge or curve:
! _Divide _Pause _Split=_No 32 _SelLast _PlaneThroughPt _SelLast _CPlane _Object _Undo _Undo


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Hi Pascal, you guessed it right. The idea is to be able to approximate the CPlane trough a series of control points. Sometimes, these points may not be sitting on the same plane.

Ideally, the Gumball itself should be able to recognize 3 or more selected control points as a reference to its “Align to object” option. However, if I select a few points or surface control points, the Gumball remains oriented relative to the World axis or the custom set CPlane. That’s somewhat counter-intuitive, because the human logic is that since the points or control points are inclined, so must be the Gumball as well. If the Gumball is upgraded to fit to the selected points, then the user even don’t need to create a dedicated CPlane for a single drag operation.



Hi John, I’m aware of the CPlane positioning options, but the idea behind my original post was to ask whether there is a way to approximate a CPlane across multiple points or control points.
Also, if the Gumball could automatically align to the selected control points of a pipe (like my example above), that would be best. It already aligns to surfaces when the “Align to object” option is active. :slight_smile: