p/low fast draft parts

[Steffen]

Your suggestion in fact is to introduce a p/0 folder.
And subsequently, you suggest to introduce a
parts/0
folder for parts, analogously.

I like the p/0 folder idea. It matches the existing p/8, p/48 folders very well.

However, I have my doubts about the parts/0 suggestion, because that would duplicate lots of part implementations, and part authors need to be aware to change both files synchronously. I probably better would like a tool side solution for this problem, i.e.,
a tool discarding all invisible geometry at render time.
I suggest this because in a scene you would need to mix normal parts and parts/0 parts to
get a visually nice image. Each time you modify your scene you need to switch. For example,
if you build 3 bricks on top of another, the 2 bottom ones will be from parts/0,
and the topmost from parts. When you add another on top, you will need to change the previously topmost from parts to parts/0. And so on.
A programmatic approach would be much more versatile here imho.

So I support your p/0 suggestion, but do not like the parts/0 idea.