Hi Sven,

re:
> Curious if I should be able to create an arc on surface ?

Using which command, do you mean with Draw curve > Arc > Center?

The arc center point draw command is focused on drawing an arc on a plane. If you pick the arc center point on a surface it will use a drawing plane with the plane origin on that point and a z axis along the surface normal.

So the arc will be on a plane something like this:





That tool does not know how to draw the entire arc on a surface because that is only possible in special cases.

But I think arc through 3 points will do it if you put the 3 points all on the sphere surface.

- Michael