# problem with arc angles

**URL:** http://forum.qcad.org/t/problem-with-arc-angles/2981
**Category:** dxflib 'How Do I' Questions
**Created:** [November 27, 2016, 1:08pm UTC](http://forum.qcad.org/t/problem-with-arc-angles/2981 "2016-11-27T13:08:01Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![Patry0t](http://forum.qcad.org/letter_avatar_proxy/v4/letter/p/5f9b8f/32.png) [@Patry0t](http://forum.qcad.org/u/Patry0t)
#### Post date: [November 27, 2016, 1:08pm UTC](http://forum.qcad.org/t/problem-with-arc-angles/2981/1 "2016-11-27T13:08:01Z")

</div>

Dear all!

I’m using opencv to fit an ellipse on a given set of points. These points are (x,y) points of an arc. I calculate the start-angle and the end-angle and draw an ellipse on it from angle1 to angle2. It works fine in openCV, but when I try to do the same in the dxf, it puts the arc to some different angles, absolutely not there where I wanted it. Can you help me understand how the opencv draws an ellipse and how the dxflib?