Which file should I choose?
Use NHP-ISO-BBS1xx-2D-CAD-Block.dwg to insert the supplied editable drawing into your layout.
Use NHP-ISO-BBS1xx-3D-CAD-Block.step to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified NHP-ISO-BBS1xx-3D-CAD-Block.step.
