I was wondering if anyone could help trouble shoot an issue with the interp curve command.
Rhino seems to be running fine, however when I try use the interp curve command when attempting to close the curve it disappears.
I have uninstalled and reinstalled rhino to no success and have attached reference photos.
First thing to check is if you are not in Rendered display mode. By default, it doesn’t show curves (after they have been created). Switch to wireframe, the curve probably was created.
If the Rendered mode situation is not the case, please run the command SystemInfo in Rhino and copy/paste the results here.
I have found a partial solution. It appears that when the degree is an even number it will not allow the line to be closed, however when set to an odd number the line works as it should. Not sure why this occurs, any ideas?
Ahh, good catch - I see that here too. I never use even degrees above 2, but it I see it also fails with degree=2. I suppose this is a bug, unless there is some mathematical limitation - however as I can successfully close a degree 2 or 4 control point curve, I don’t think that’s it.
Not sure how this applies here - it does apply to _Curve - as I can create for example a degree 5 curve with InterpCrv by picking only 3 or 4 points. Of course, those are not the control points, the curve created is indeed degree 5, but has 8 control points (open, 3 points picked) or 12 (closed, 3 points picked then close). So maybe the help item needs a bit better explanation.
@Helvetosaur
I meant to say it was not a problem in v5 because it was not possible to set even degrees. Like @mikko said in RH-22340, there could be bugs with even degrees and not be able to close the curve is one of them. Thanks.
Some more observation:
Curves with an even degree can be smoothly closed only when Knots=Uniform.
Curves with an even degree and Knots=<Any> can be closed when Sharp=Yes.
I think it is a bug rather than a limitation. So I don’t add a note to the topic about these things.
I changed the description of the degree option in the Curve and InterpCrv commands as below:
For Curve command Degree
Specifies the degree of the curve.
The resulting curve will not be the degree you request unless the control point number is at least one more than the degree number.
For InterpCrv command Degree
Specifies the degree of the curve.
Unlike the Curve command, the resulting curve is always the degree you request even if only two points (start and end) are picked.