Dear friends,

I am trying to create a solid object in the shape of the inverse of an imported body so that the inverted part can be cut and modified as any normal SW feature can be. The aim is to use the shape of the inside of a small equipment case (a pelican 1010 case) and to 3D print a custom insert that fits snugly and houses some hardware. (Please note that I'm unsure of exact SW parlance so if I use the words 'body,' 'surface' or 'object' I'm not intentionally trying to refer to specific Body, Surface etc. features.) Using SW2012 I have imported the shape of the item as a solid (STEP file supplied by case manufacturer ). I'm showing it here sectioned so that you can see that it is solid, and I have hidden tangential lines which illustrates that all the curved faces meet in a orderly and law abiding way:

[Attached as Peli1010 bottom.sldprt]

You'll note that the object has a hole in one side. The uppermost 'flange' is flat and can be sketched upon.

What I want to do now is make a part that is the inverse of the inside of the case, i.e. make a 'negative' of the 3D volume, or take a 'cast' of the inside.

I've tried a few techniques...

1. Close the hole by deleting the faces that form part of the hole and copy replacement faces about the centre axis, knit those together, and then Surface Cut an extruded feature
2. Tinkering with mould tools
3. Copying faces and vertices into a new sketch

... and none of those yet work. Specifically the Surface Cut feature looks like the way to proceed but I am unable to use the imported shape to effect the cut. I imagine there is a way to make a blancmange in SW but I'm yet to figure it out!

Any help gratefully received!

Graham