I noticed that .obj files does not contain material information in them, instead blender creates a .mtl file along with it. As far as I know balsam does not accept .mtl files along with .obj so instead I tried other formats. I tried all formats in https://doc.qt.io/qt-5/qtquick3d-tool-balsam.html#supported-3d-asset-types . GLTF2 (.gltf, .glb) format worked for me. However the other formats that blender can output did not give material information.