Offset of a line is not a line. I wish it was

The offset of a line is not a line, but a more complicated object, which has (I guess) the same geometry. I wish it was just plain line. Why?

Well, when I ask RhinoCam to engrave along a real line, it programs the tool just to move from one end to the other. When I ask RhinoCam to engrave along the offset thing which is not really a line, then RhinoCam inserts a point halfway along. And THEN the controller on my CNC router screws up.

Yes, it SHOULD all work, but it doesn’t. The real fault is in the CNC controller … and I’m trying to get their attention. But it would be nice if Rhino special-cased Offset to offset a line to a line. And maybe a circle to a circle too …

Oh: this is an old version of Rhino … 4.0. But I’d be surprised if it was different in later versions …

please share your file. usually a line which has two points offsetted will have 2 points either, the same with a circle. if you would create a line and a circle from scratch and try for yourself i am sure you would quickly find that this is the case. in anyway it is pretty difficult to make a judgment without some geometry.

one thing you can try is to use SimplifyCrv, which makes simple lines out of straight lines with too many points but only if they are are truly in the same tangent, it also simplifies circles back to a simple circle.

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Hello- an offset of a line should certainly be a line - I do not recall about how V4 handled this but normally I would expect a line. Please post your example.


Sorry to be slow to reply … I wasn’t following this closely.

Draw a Line for 0,0 to 0,1
Offset it by 0.3

Original is ON_LineCurve (inList)
Offset is ON_NurbsCurve

RhinoCAM produces a .nc file with just a beginning and end for the original line, but produces a .nc file with an intermediate point for the offset curve.
They should cut the same path, but (I think) the controller on my cnc router has a bug in it and screws this up for near-vertical lines. (Certainly neither Rhino’s or RhinoCAM’s fault.)

PS: Try the same with a circle. The offset of a circle is a Nurbs curve …

I just checked out of curiosity, and can confirm this is the case in Rhino 4 for lines, but I don’t see it happening on circles.
FYI: In current Rhino 7 SR 25 lines stay lines, circles stay circles.

What you could do is run _SimplifyCrv afterwards.

This has been fixed since V5… Time to upgrade?

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after offset should/ might help.
(my guess it existed in V4, but not sure)