Like stated in #57, the setMaterial() method of QgsPolygon3DSymbol is renamed in QGIS 3.30 to setMaterialSettings().
Unfortunately, this is API breaking. setMaterial() works right now only until QGIS 3.28; setMaterialSettings() only from 3.30 on.
It's not a nice fix, using both methods in a try except block. But now the plugin should work with all QGIS versions.
Like stated in #57, the setMaterial() method of QgsPolygon3DSymbol is renamed in QGIS 3.30 to setMaterialSettings(). Unfortunately, this is API breaking. setMaterial() works right now only until QGIS 3.28; setMaterialSettings() only from 3.30 on. It's not a nice fix, using both methods in a try except block. But now the plugin should work with all QGIS versions.