To delete a previously imported 3D cell, do the following:
Select File> 3D Cell Import to open the 3D Cell Import dialog box.
Select the cell name from the drop-down list. The 3D File field displays the path to the 3D file.
Click the Delete button.
Click Yes in the message box asking if you would like to delete the 3D cell.
The selected 3D cell is deleted from the 3D PCB Viewer. However, the file itself remains in the design’s database. The 3D PCB Viewer cannot delete cells from the design’s library.