@Joshika_Namani Which version of Qt do you use? I think that using Qt6 is a better option but here is a doc for Qt5 https://doc.qt.io/qt-5/qopenglwidget.html if you want to see.

https://dev.opencascade.org/ may be interesting for you.

@timob256

This is some years old but maybe it helps.

Also found this:
https://github.com/GarageGames/Qt/blob/master/qt-5/qt3d/src/render/io/objloader.cpp

@Lukadriel Hi, One year passed and still waiting for the proper example. Did they give any tips?

'AssimpImporter' should be able to import 3D models supported by 'Assimp' library, but there is no such class in Qt, at least not in Qt 5.5.1 (Kubuntu 16.04.3), Qt 5.10.0 (Windows 10 and Kubuntu 16.04.3) and Qt 5.10.1 (Windows 10).

Personally I wouldn't recommend you using Qt3D (at this point), since this module still looks like a technology preview although is not marked as such.