You can delete selected objects with the Delete key just like other elements in Softimage (see Deleting Elements). As an alternative, you can use the Delete Objects tool to delete objects interactively by clicking on them in the views.
To use the Delete Objects tool
Press the Backspace key to activate the Delete Objects tool, and then click on the objects you want deleted in a 3D view or
schematic. To deactivate the tool, press Esc or activate a different tool.