Well, old knowledge about WZ1 still works in WZ4, that good news for me
Let me explain how it works in WZ1
when you use operator like select it will cut some parts from object and you need to place green ADD operator after your whole mesh complete, then CPU will start calculating from this point like this is solid mesh, if you don't place that operator then CPU will calculate all primitives that you use to make mesh (in 2004 year we saw much graphics performance improvement if we use ADD operator and also this point included in WZ1 tutorial on multiples cube example)
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