Adding an Interpolation Point
To add an interpolation point to an interpolation spline:
1. Click Interpolation Spline in Geometry.
2. Click Modify Point in Interpolation Spline.
3. Click Add in Modify Point.
4. Click the spline to which you want to add an interpolation point.
5. Click the position on the spline where you want to add the interpolation point.
When you add an interpolation point, the shape of the spline changes accordingly.