Control point Splines - Issue with Closed & Minimal point count

If you are having problems with QCAD, post here. Please report bugs through our Bug Tracker instead.

Always attach your original DXF or DWG file and mentions your QCAD version and the platform you are on.

Moderator: andrew

Forum rules

Always indicate your operating system and QCAD version.

Attach drawing files and screenshots.

Post one question per topic.

Post Reply
CVH
Premier Member
Posts: 3365
Joined: Wed Sep 27, 2017 4:17 pm

Control point Splines - Issue with Closed & Minimal point count

Post by CVH » Fri Feb 24, 2023 7:15 am

Andrew,

Discovered while testing the upgraded DrawFromCSV 3.06 that supports ellipses.

It seems I can not draw Closed Control Point Splines with the minimal required point count.
Referring to this: https://www.qcad.org/rsforum/viewtopic. ... 864#p40063
The red spline shape is drawn as closed, degree 3, from the 4 points.
Properties after creation are Periodic Closed with 4 control points but obviously it isn't displayed as closed at all.

One can not explode this shape, it results in a Null-length Polyline entity with 2 identical vertices.
To explode one has to select the incorrect shape and that may be challenging, cross selection or intersecting works best.

When the file is reloaded the shape seems to be correct (White).
Properties are then: NOT Periodic Closed with 7 control points.
Point 2 is seemingly replaced by 4 others and for some reason it isn't considered closed anymore.
This shape can easily be selected and explodes correct.

SplineIssues.png
SplineIssues.png (6.27 KiB) Viewed 11297 times

I can replicate this for quadratic Control Point Splines with 3 points.
With one extra control point for quadratic or cubic all seems fine.

Another side-note is that closed splines do not explode to closed polylines. :shock:

To replicate one has to actually draw the spline shape in the provided drawing.
I can't include the error because it reverts on Re-loading the drawing.
Tested in Pro 3.27.6; Pro 3.27.8; CE 3.27.9 (Not renewed my licence yet :oops: )
Can anyone test this in the latest Pro release?

SplineIssues.dxf
(150.4 KiB) Downloaded 328 times

Regards,
CVH

Post Reply

Return to “QCAD Troubleshooting and Problems”