Merge, Inheritence, Copy Geometry and Publish Geometry

Publish Geometry is a way to bundle together geometry in one part for easy reference by another part. It is used for Copy Geometry features, to re-use geometry in another part as reference. By using Published Geometry, you make it simple and fast for others to select the correct items when using Copy Geometry. Otherwise, there is the possibility that different people could grab different (incorrect) reference geometry. Copy Geometry allows you to grab features and refrences from one part to use in another part. It is indispensible in Top-Down design, where you want separate parts to share common references. In my case, I can use Copy Geometry to grab the internal surfaces of a cast part and incorporate them into a separate part that represents the 'core'. Once the surfaces of the inside are in my new part, I can close them and 'Solidify' to make a representation of the 'core'. Merge/Inheritance is the way you incorporate one complete solid part into another solid part. Merge inserts a monolithic solid feature representing one part in another part -- no changes allowed in the new part. Inheritance does almost the same thing, except the solid feature is not monolithic, you have access to the individual features and therefore you can alter the Inheritance feature in your new part. We use Merge/Inheritance to handle cast and machined parts. Part 'A' is modeled as a casting. Part 'B' is created to represent the "as machined" version of the casting. Inside Part 'B' insert a Merge from Part 'A'. Once done, we can now make cuts to represent the machining operations. If we then change the casting (Part 'A') those changes ripple into the machined casting (Part 'B'). Merge also allows you to make a mirrored copy of a solid part. This came in handy once when we had a design with a left-half and a right-half. We modeled the left-half then used the Merge (with mirror) to make the opposite. Merge will also allow you to make Cut Outs. We have used this functionality to make assembly nests or other such fixtures. Simply make a block of material in Part 'B', then Merge/Cut out Part 'A'. Inheritance is relatively new. I haven't used it. But it seems ideal for cases where you want to to model a part that is a lot like a previous part, but you want to make subtle changes in dimension. I can imagine this would be the case if you were making a new pistol and wanted hand grips almost like another model. You could inherit the grips, and then alter dimensions to make the new grips fit a wider hand (for example). I'm sure PTC can offer other, better examples.