Thu, 01/26/2017 - 13:24
Forums:
Hi everybody, I'm new in the forum and I'm starting to use OpenCascade to read IGES files.
I'm using Qt library with a QGlWidget area in wich I draw my geometric entities like lines and surfaces with the basic OpenGl functions (GL_LINES, GL_LINE_LOOP..).
I've this question: Is it possible to draw the OpenCascade geometries (for examples the curves and the surface of the iges file) in my GLarea or I must do in a separate GlArea. I would like to draw both openCascade geometries and my geometries in the same window.
I don't understand if the two things can coexist in the same Gl area.
Fri, 01/27/2017 - 13:18
Dear Gabriele,
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OCCT 3D Viewer can be combined within other OpenGL renderer in various ways,
as rendering performed on top, or embedded into scene as custom OpenGl_Element.
The most obvious example of such combination is Open CASCADE CAD Assistant,
where Qt/QML draws user interface controls using OpenGL on top of OCCT 3D Viewer:
https://www.opencascade.com/content/cad-assistant
However, while rendering 3D elements, you should be aware of complexity and multi-pass techniques used by OCCT 3D Viewer.
Therefore, it is preferred to use low-level OCCT APIs (custom AIS_InteractiveObject computing primitives arrays,
or using OpenGL calls directly within custom OpenGl_Element) for more straight-forward integration into rendering pipeline.
Package OpenGl in OCCT provides a lot of useful classes wrapping OpenGL routines in object-oriented way.
See also class VUserDrawObj in file src/ViewerTest/ViewerTest_OpenGlCommands.cxx as short introduction
to embedding of low-level rendering routines into OCCT 3D Viewer.
Best regards,
Forum supervisor
Tue, 02/07/2017 - 16:42
Hi, thank you very much for your answer. It's very helpful for me. The cad-assistant is very interesting to start to understand the OpenCascade world.