Posted by LordOfBikes on Sep 03, 2023; 9:05am
URL: https://forum.librecad.org/Distance-along-a-curve-tp5723382p5723390.html

Spline support is very limited in LibreCAD.
They can be drawn or opened from existing files, but when it comes to modification many tools don't work.

For an exact straight distance usually a circle is used. Then  the intersection is the desired point.
But, I just tested it, this doesn't work for splines too, neither does Snap on Intersection work nor can I divide the spline near the intersection.

Depending on the quality you need, you can try this:
- save the drawing in R12 format (keep a copy in DXF2007!)
- close and reopen the R12 file
- the spline is now just an approximation, a polyline with straight line segments
- explode the polyline, because polyline has similar restrictions
- now you can measure and lengthen, or divide the segments at desired points

If you mark the points in the R12 file, you can copy/paste them back into the DXF2007 file.
You probably still can't divide/shorten/lengthen the spline, but it may help anyway.

This R12 trick works, because DXF R12 doesn't know splines or ellipses and on save they are converted.

Armin