Loft Help Please

How do i manipulate this loft so that the flat strip is narrowed symmetrically. Like pulled in. So there is a draft on the loft walls. Is this possible?

Loft manipulation.3dm (452.1 KB)

OffsetCrvOnSrf the edge curves along the base of the inset by the desired amount. Then create new sides and base.

When you say draft I assume you are trying to make this so that it can be molded and draft is needed so that the part will draw from the mold.

The tool for making drafted surfaces is ExtrudeCrvTapered. That tool will make a very ugly dense surface so its best to refit or rebuild the surface to make the draft surface usable.

The first thing I would do is build the parting surface. The parting surface as you have designed this is very close to flat so you might want to modify your part slightly to make it conform to a flat parting. The Silhouette command will give you the split line for making the parting. I used Fin to make the parting surface.

The enclosed file shows how I would make the drafted walls of the snaky slot . The green surfaces are the parting. I used 2 degrees draft. The way to check the draft is DraftAngleAnalysis.
slot with draft.3dm (3.5 MB)

i have no idea what you were going for here. i just want to narrow the path and loft it together but i cant seem to figure that out. It seems you were trying to split the body apart to make a mold. I just want to 3d print it with the shape im looking for

im trying but i keep getting select open or closed curves but not both.
what am i doing wrong here?

Loft manipulation.3dm (333.8 KB)

The offset curves are open, not closed. Try using CrvEnd to identify the locations of the open ends of the curves, and then close the curves with Match.