Duplication part to part
For example, these 2 parts :

Restart the function
to create parting lines on the other part.
Instead of asking a new proposal, click on
DUPLICATE
in the list.
Select the original part.

Select the destination part.

The software builds on the new part the parting lines regarding the common edges on both parts.

You can end the parting lines with the usual tools.
Topsolid online Help Index