Adding an Arc via API

[DanRathbun]

@geoffreyhawkesford

Thanks Dan, it hadn’t occurred to me that add_arc was designed to produce an acw arc which would be fine.

I think it may be the norm for 3D and CAD applications. It was the same in AutoCAD.

@geoffreyhawkesford

but …

mod.entities.add_arc [10,0,0], [1, 0, 0], [0, 0, 1], 10, 270.degrees, 0.degrees, 6

… draws unconnected clockwise edges.

I just tested this snippet. The resulting edges do have an associated ArcCurve object. (FYI, SketchUp does not have geometric polylines like AutoCAD does.)

@geoffreyhawkesford

From other tests that I have made it seems that
if (end_angle - start_angle) > 0
then it draws correctly an acw group of edges, connected.

but
if (end_angle - start_angle) < 0

then it draws incorrectly a cw arc of unconnected edges.

The drawing in CW order may be another undocumented quirk of this factory method. (I had not used it in quite awhile, so perhaps I’m not remembering how it works entirely. Search this category on the method name and you may get some hits.)

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FYI: (click to expand)

• [How to] Post correctly formatted and colorized code on the forum?
• Ruby Learning Resources [WikiLists]
• Issues · SketchUp/api-issue-tracker

Also …

Ruby best practices says that all instance method calls should use parenthesized argument lists. The exceptions are the methods from Kernel, Object, Module and Class that have “keyword status” when called from within a module or class definition and the receiver is self.
The interpreter does not enforce parenthesis, but might need to work a bit harder in it’s parsing. Not a big deal if you think it reads better for you. (There are still many bundled Ruby library files that omit parenthesis around instance method parameters.)