There is no function to create a solid from assembly

[adam-trhon]

Creating a solid from assembly has following use cases:

• Exporting the assembly to format that does not support multiple parts, for example stl
• Using assembly in boolean operations

[adam-trhon]

I ended up using this (heavily copied from Discord discussion):

def generate_solid_from_assembly(assy, fuse=True, name_filter_re=None):
    result = []
    
    for name,val in assy.traverse():
        if name_filter_re and not re.match(name_filter_re, name):
            continue
        
        shape = val.obj.val()

        # get location
        loc = val.loc
        current = val
        while current.parent:
            loc = current.parent.loc*loc
            current = current.parent
        
        result.append(shape.located(loc))

    result = cq.Compound.makeCompound(result) 

    if fuse:
        result = result.fuse()

    return result

Notes:

• By default the function fuses the compound. This is slower, but I assume it always returns the right result. Without fusing, the result may behave strange when used in boolean operations. If the user needs to speed up the process, fusing can be disabled by an argument.
• I think there should be some filtering. This is a necessity when one wants to perform a boolean operation and have the operands positioned using the constraint solver. As I could not figure out anything better, I filter based on names.

Please review and comment.