I have imported a 3d model from Archicad to Blender. I want to render interior but I'm not able to enter the interior spaces.
You can place a camera inside your mesh and use the 'Lock Camera to View' in the view tab (N). Then go to camera view (Numpad 0) and navigate with camera locked to view. You can deactivate lock once you get the right view for render.
You can also separate parts of the mesh and then you will be able to hide the parts you want in Object Mode. In Edit Mode, Select all > P > Separate by Loose Parts.