Which file should I choose?
Use SMISSLINE TP_ZLS260_2D.dxf (revision A) to insert the supplied editable drawing into your layout.
Use SMISSLINE INCOMING BLOCK 63A L1_L3.step to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified SMISSLINE INCOMING BLOCK 63A L1_L3.step.
