rs.Command( _arc

Scripting
1

Hi,
There is probably a very simple answer to this question:
rs.Command("_Arc 0,0,0 0,10,0 10,0,0") dont return an arc.

I have found out that the last instance (the end point) is for me always reprecenting an angle, and not point as I would prefer.
How do I change the last instace to point

Many thanks in advance

2

Couple of answers:

rs.Command(_Arc _StartPoint 0,0,0 _ThroughPoint 0,10,0 10,0,0)

You need to explicitly call out that you want an arc through a point in the command string.

You could also just use the native rhinoscriptsyntax method:

rs.AddArc3Pt(start, end, point_on_arc)

See the rhinoscriptsyntax help for more details on that method.

HTH, --Mitch

3

Hi Mitch,

I want to achive the black arcin picture below.
Your options resulted in the red arc.
I can’t find any easy rhinoscriptsyntas method for this so I thought that the rs.command() whould be the best option.

Do you have any other suggestion? Otherwise I will have to rewrite the program alot to make this work.
Thanks for the help Mitch!

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4

Well, there is no direct Rhino command for arc from Center, StartPoint, EndPoint because there are an infinite number of arcs that can be built from these 3 points - it lacks a radius definition. So either you want to define it with Center, Start, Angle, or Start, End, Radius… The problem with the second is that there are two possible arcs, so you manually need to decide (Rhino makes you click on the screen). That makes it tricky to macro, but it’s possible.

You can program that either with rs.Command() or use the native rhinoscript syntax method rs.AddArc(plane, radius, angle_degrees). If you use the rhinoscriptsyntax method and you only have the center, start and end, you will need to do a bit of calculation first.

rs.Command("_Arc 0,0,0 10,0,0 90")
#or
rs.Command("_Arc _StartPoint 10,0,0 0,10,0 _Radius 10 _Enter 0,0,0")

With native rhinoscriptsyntax it might look like this:

import rhinoscriptsyntax as rs
plane=rs.WorldXYPlane()
rs.AddArc(plane,10,90)

–Mitch

5

Thanks for the very quick replys.
I will look into it, but probably have to look att this from a nother point of view.
Thanks again for the support.