Counterclockwise arc from Startpoint, Endpoint and Centerpoint

I’m stuck on something wich seems simple but I cannot seem to figure it out.
I’m trying to create an arc that runs counterclockwise where I have 3 points: The start point, End point and Center point

I came across this topic C# how to create a Arc(center, start, end) but the solutions given there don’t work in all cases considering the arc needs to run counterclockwise

This is what I have so far

Works in some cases

But doesn’t as soon as I cross the imaginary line connecting start and endpoint:

240126 Arc Stpt Endpt Cpt counterclockwise.3dm (39.1 KB)
240126 Arc Stpt Endpt Cpt (15.5 KB)

Your measured angle have unspecified plane, so it will return the “shortest” angle between two vectors.
With unspecified plane you’ll never get angles greater than Pi.
Instead, by specifying a plane, you can measure the whole range 0 to 2*Pi …

Use your Pl plane as input for P for Angle component.

That seems to works for the position the points currently are in:

But as soon as I rotate everything 90 degrees I get a wrong solution as the curve is not counterclockwise:

I think this was the same issue for the example in the other topic I posted.

I haven’t checked your files, sorry.
If your 3 points do NOT define the plane you are working to, then I suppose you want to work planar world XY plane? (otherwise “counterclockwise” means nothing…)

In that case, create a plane simply with a XY plane component, origin at your center, then align your plane with the vector origin-start, then again measure the angle as said before, using that plane.

2024-01-26 13_14_59-Window

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@maje90 Thanks! Seems like I was using the wrong way to construct the plane. In my solution the plane had no defined Y access which I think was what’s causing the issue.

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