After downloading the 3D model .STEP file from SnapMagic and importing both the footprint and 3D model in Altium, when you go to the 3D view, you notice that the 3D model does not show up. If you try to place a different 3D model from the default library Miscellaneous Device, you see the 3D model.
To solve this issue, simply click Tools > Update PCB With Current Footprint.