Hi Brian, by the way the Draw curves > Circles > Tangent command can generate a circle tangent to 3 other curves currently.

> but the question is, can the center of a circle be found like the following var x1 = code which does not work:

Sorry no, currently there isn't anything set up for returning circle properties to script, the only things exposed specific to curves currently are:

crv.isClosed property,
crv.getFacesOfEdge()
crv.getUVCurvesOfEdge()
crv.getStartPt()
crv.getEndPt()
crv.getLength()


> Second question, is the c1.radius code OK?

I don't think so - I'd think it is returning "undefined".


> Third question, is a circle just another curve, or is there objectpicker
> code to restrict selection to circles?

Sorry no there isn't currently, the current ones are just by more general object type than that:
allowCurves();
allowStandaloneCurves();
allowEdgeCurves();
allowFaces();
allowBReps();
allowPointObjects();
allowEditPoints();
allowTopLevelObjects();

Probably a good way to add a more flexible one would be to let you pass in a function that the objectpicker would then call to decide if an object should be allowed to be picked or not.

Those are some things that I can add in for you in v4 once it's underway. Not too much longer...

- Michael