I’ve been setting the Cplane more lately and have run into an issue I don’t understand. In the enclosed file
OffsetCplane.3dm (55.4 KB)
I drew a rectangle with lines first in the Front View with its normal CPlane. Then I created a CPlane using two lines created in the top view. One line goes off at 45 degrees and another that starts at the same place goes off at 90 degrees to that line. Then I set the CPlane using 3points using those two lines as guides for the X and Y axes. Then I tried to offset the line which goes off in the new X direction. The offset line will only offset in the XY direction even if I click the InCplane option. I can draw other 3 dimensional things in this CPlane as I would normally draw them in any plane orientation. Clearly there is something I’m not understanding about the offset command that I wish I did. Any help appreciated. I looked at the write up on the Rhino help site but it didn’t help any.
offsetting a curve with _offset
with in cplane checked / turned on will always offset in the current cplane, meaning that the connection lines of related points will be horizontal / parallel to the cplane.
in cplane unchecked rhino will try to guess which plane fits best. if a curve is planar, this plane is used (instead of the cplane).
this behaviour is quite hard to understand if you work with lines - try it with a closed planar Curve
example
this should explain it better:
the rounded rectangle black is offset twice
green in cplane is unchecked / off
red in cplane is checke / on
your file
if the red line is wrong,
assuming you want the green
you need the cplane as in the screenshot - if you insist on using offest…
alternatives
copy and move both offer a vertical option.
you can also enter relative coordinates with a z-value
_move (first click anywhere) r0,0,123
r = relative
0 = x
0 = y
123 = z
to move 123 up
hope this helps - kind regards -tom
Thanks, Tom. I finally realized that probably I needed to do the Cplane as you showed in the second screen shot. But, that makes what I’m doing overall more awkward. But, the good thing is that you showed me a good trick that I hadn’t thought of in doing a relative move. I’ll give that a try. I’ve been using the copy in place and move using the gumball already. That works fine.