circle draw with visible "polygons" if set in a TopoDS_Compound

I'm using OCC 6.3 with the 3D Viewer and AIS_InteractiveContext.

I have set the SetDeviationCoefficient to 1e-4, so that the "polygon" of a circle is not visible.

If I draw a circle (TopoDS_Edge) direct in the viewer the "polygon" is not visible. -ok.

If I put the same circle in a Compound, the circle is drawn with a visible polygon. -strange! It seems that the SetDeviationCoefficient, SetDeviationAngle and SetHLRDeviationCoefficient has no effect on AIS_InteractiveContext.

Is there another parameter were I can obtain a smooth circle (wrapped in a compound)?
Any hints are welcome.


Forum supervisor's picture

Dear PeterZ,
There are a lot of changes since OCCT 6.3 to 6.5.1 that can take effect on result.
We didn't detect any difference between presentation of a circle as a single edge and the edge wrapped in a compound (see the attached picture with presentation of both cases and Draw script below):

pload ALL;
circle ccurve 0 0 0 1;
mkedge ce ccurve;
compound ce cc;
vdisplay ce;
vdisplay cc;
vsetshading cc 0.0001;
vsetshading ce 0.0001;
vsetshading cc 10;
vsetshading ce 10;

Both shapes are shown bit-exact in OCCT6.5.1 DRAWEXE viewer when deflection parameters are equal.
So, the problem is not reproduced in OCCT 6.5.1.
I suggest you to you the recent version of OCCT.

Forum supervisor's picture

now the picture is attached.

Peter Zbinden's picture

Hello supervisor,
Thank you for your script test. The same test running on OCC 6.3 gave the attached picture. The polygon is only visible if you increase the window. Could you please verify if this effect is not visible on 6.5.1. Thank you very much.


Forum supervisor's picture

Hi PeterZ,
As I noticed before the problem is not reproduced in OCCT 6.5.1.
We didn't detect differences in presentation of both cases in Viewer3d including full screen window.
I hope you can easy check it by yourself using recent distribution of OCCT (6.5.1),
which you can find at the page

Peter Zbinden's picture

Hi supervisor

Thank you very much for your support.

Peter Zbinden's picture

I have changed now to 6.5.3 but the polygons in TopoDS_Compound are still visible!
Same as in version 6.3.

Regards Peter