How to create periodic closed Control-Point splines?

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CVH
Premier Member
Posts: 5009
Joined: Wed Sep 27, 2017 4:17 pm

How to create periodic closed Control-Point splines?

Post by CVH » Thu Feb 27, 2025 9:17 am

No matter what I do, it seems to be impossible with QCAD.


For cubic splines the minimal point count is 3+1 = 4 Control-Points.
These are even rendered faulty after creation.
-> See this forum topic 9870 (Feb 2023)
-> See bug report FS#2453 (Feb 2023)
Reloading such a file seems to show the intended shape ... With 4+3 = 7 Control-Points and open!

With more than 4 Control-Points the shape is rendered as intended on creation.
But it does not remain periodic closed afterwards ... Always N+3 Control-Points and NOT Closed Periodic!


Very similar for quadratic splines:
- Minimal point count is 3 ... False rendering on creation ... Returns as 3+2 = 5 Control-Points and open!
- With more than 3 ... As intended on creation ... Returns as N+2 Control-Points and NOT Closed Periodic!

Additional question:
:arrow: Does that occur on saving the file or on loading the file?

Regards,
CVH

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