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FS#1012 - Make threshold from which arcs are approximated as lines configurable

Attached to Project: QCAD
Opened by Väinö Forss (ayni) - Sunday, 19 January 2014, 16:52 GMT+1
Last edited by Andrew (andrew) - Tuesday, 21 January 2014, 15:17 GMT+1
Task Type Feature Request
Category QCAD (main)
Status Closed
Assigned To Andrew (andrew)
Operating System All
Severity Low
Priority Normal
Reported Version 3.4.5
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No


Tried to draw a guitar and when drawing top arch (R=10600 mm), I noticed that when arc length is less than 5% (in ths case less than 530 mm) of arcs radius arc appears totally straight both in screen and print.
Data is stored right, details are right, reference points are right, snap on entity goes right, but the line appears totally straight.

I have iMac mid 2011 with Mavericks and latest Qcad.

This task depends upon

Closed by  Andrew (andrew)
Tuesday, 21 January 2014, 15:17 GMT+1
Reason for closing:  Implemented
Additional comments about closing:  https://github.com/qcad/qcad/commit/3b4b 9d9e6856d0156d173fdf4eabbe08f48e31b2
Comment by -- (clive) - Monday, 20 January 2014, 12:55 GMT+1

This is expected geometric principle. Try manually using a compass and pencil you will get the same result with such short arc lengths.

To achieve what you need try using the spline tools, maybe the 'Fit to Points' option.

Comment by Andrew (andrew) - Monday, 20 January 2014, 16:19 GMT+1

This is indeed expected behavior.
There is a threshold below which QCAD approximates arcs as straight lines.
I will change this report into a feature request to make that threshold configurable.