[L98FIERO]

I'm trying to subtract a part from a solid so that I can make a surface like a mold in a block. I have a stp file of a part that is way out in space relative to it's origin and there are no flat surfaces for references. What I want to do is have the swept surface low enough in a block of stock that I would get the whole surface reproduced. I've attached a zip of the part, it's about 20 inches long x 1 inch wide. Anyone have any suggestions as to how to do this, though I've had BobCad for a long time I've never had he opportunity or the requirement to have to do this but I'd like to learn how to do it.

[BurrMan]

See if this is the surface you were describing.... What you will want to pay attention too, is the need to remove certain fillets that would create "undercuts". Since it curves around in so many directions, you have to make a decision on "how to rotate and place" the part, that will grab the surfaces you want. In this model, I just guessed at what you want and arbitrarily placed/rotated the original model, then I just deleted and surfaces that would make an undercut, and extruded the remaining edges up in Z past the 0 mark, to make vertical walls, then cut them planar at Z 0 and made a cap.

This is a V24 file.

[L98FIERO]

Thanks, Burrman, that looks like what I'm looking for, I just need to figure out how to do it. I tried to do that by unstitching all the surfaces and remove the un-needed ones and then extrude curve up an inch and then add them all back together with Boolean add but couldn't get them to add back together. Obviously I did something wrong.

[BurrMan]

Boolean is more for 2 intersecting solids.. To join surfaces together you use "stitch surfaces to solid" under the untilities menu.

[L98FIERO]

I missed that part. What I meant was that I unstitched the solid, removed the 'top' surfaces and then extruded the surfaces in the Z axis and then tried to add them together. When I tried that I tried adding two pieces together and then adding a third to the two that has been combined and all three disappeared Obviously I'm missing something .

[BurrMan]

I extruded the surfaces in Z

You'll really want to pay attention to this part. Depending on the position/rotation of the object, that extrusion will produce malformed solids ( Surface edges that intersect and overlap themselves as they extrude up, hence the disappearing as you use the boolean command)

So go ahead and do the extrusion, but then inspect the result for this. Especially in the little tight corners where the surface edges move around in Z more than x and y... If you find the self intersecting surfaces, delete them and rebuild them from the surrounding surfaces edges.

If you want, post a model of the extruded surfaces you are talking about and they can be looked at.