jacg
commented
1 year ago Not sure what is silly about air in steel in air.
The point is that placing any volume entirely within another effectively is a boolean subtraction solid. This is how G4 geometries are designed to work.
You should not use boolean solids for anything that can be done (without too many contortions) with plain old placement.
Examples of what you should not do with boolean solids (because placement works just fine):
- Place one thing entirely inside another
- Place something next to something else
Examples of things that might sensibly be done with boolean solids:
- Make a shape[^1] from the intersection of two shapes.
- Make a shape from the union of two intersecting shapes.
- Make a shape by removing part of another shape.
In summary, I think that boolean solids are a reasonable approach if you combine two volumes which have a non-trivial[^2] intersection.
[^1]: The official G4 name is "solid" but it's a really crap and misleading name: conceptually they are shapes and most definitely not solids. [^2]: The intersection is neither empty, nor the whole of one of the volumes.
gonzaponte
The gist of it is that boolean solids are less efficient and for the majority of cases it is better to use nested volumes; even if it implies doing something silly like placing an air volume inside a steel volume inside an air volume.