Non uniform scale from a given point

Rhino Developer
1

Hi,
I have an issue when using Transform.Scale(plane, x, y, z) in RhinoCommon. As you can see from the image below I am scaling from the purple dot, where the arrow points. The resulting geometry is however somewhat translated. Anybody has an idea why this is happening?

image
image.png1306×802 12.5 KB

The code that performs this scale is roughly this:

var scalePlane = new Plane(purplePt, Vector3d.ZAxis);
var trafo = Transform.Scale(scalePlane, scalingFact.X, scalingFact.Y, 1.0);
var nuCurve = sampleSizeCurve.DuplicateCurve();

nuCurve.Transform(trafo);
return nuCurve;

am I doing something wrong?

Thanks a lot
Alberto

2

Hi Alberto,
What behaviour do you expect? That the curve perfectly aligns with the original one after performing the scaling? Because that’s not possible unless you have a straight line as input. I don’t see anything wrong with the result.

3

hi @Alberto, what type of curve is nuCurve ?

_
c.

4

Yes, that was more or less what I wanted to have (the distance is < 0.002) if I use the _ScaleNU command the result is somewhat better aligned.