BOM’s by design are meant to list everything in a design. This is common in all CAD software. In SpaceClaim, all components gets listed in the BOM. If you want a body to not be in the BOM, you have to move the solid out of the component, so it is at the top of the structure tree. You can drag and drop, or cut and paste the solid(s) to do this. The only other way is to hide the parts. The properties for the BOM have a setting “hidden components”. If you set it to do not include, and hide the components, they won’t show in the BOM