"A single contiguous solid" is the original concept for Part Design. Best to think of it as the "Body Design" workbench.
There is no rule for this.
Part feature doesn't have to be but indeed body feature currently has a single solid requirement. Therefore what you could do is to first create a Part feature and add two Body features in it. Inner and outer ring will therefore be created as a separate Body features. PartDesign_ShapeBinder can be used to reference geometry from another Body feature. Useful to get more parametric design, if that is desired. Next step would i guess be to create a Part Sphere, use a Draft Array on it. Drag and drop the result in the Part feature.
A more correct term for Part and Body would be container rather than feature. A Body container holds features. A Part container can hold anything (even meshes), except for PartDesign features.
Well for all intents and purposes, it's both. For someone who purchases a ball bearing, it's obviously a part. For someone who manufactures it, it's an assembly.
I've said nothing until now but I really dislike that term. Calling it "Body Design" oversimplifies the methodology. It's like saying you're doing "hammer design" because you're mostly using a hammer in your work. Body is a term that is widely used in CAD to define a single-contiguous volume, which may be solid or not (so a body may be an enclosed shell or a solid). Just like in OCC the term "shape" is used to define most entities apart from meshes. I bet you that no CAD program has ever used the term "Body Design". PartDesign is not just about making bodies. Body is just a tool you use to build the stuff you want.
We can use a different name in the future, but ATM they are named Part and Body. Therefore user is inserting Part feature and Body feature. If somebody would ask, what is Part feature i have just created? What does it do and for what purpose it can be used for. Then i would provide more clues, such as it's a container, you can put geometry in and move everything around after. I used to suggest it provides local coordinate system, but now local coordinate system feature was introduced, and therefore likely i won't mention that anymore. As some would likely try to put geometry in a local coordinate system feature ...
Sorry, not knowledgeable enough for this one. But I'm not sure you want the program deciding how many Bodies are in your design.kefir wrote: ↑Wed Feb 27, 2019 9:09 pmIf a body is split into two distinct shapes by an operation such as my groove, perhaps it would make sense to split these shapes into separate Bodies in the FreeCAD document? There may be great reasons for not doing this, but from the perspective I'm seeing it, that seems to be an accurate representation of what is actually happening.
Part and Body are not features, they are containers. This is the old "reference constraint" contradiction all over again.