I would think Intersection Priority is the one parameter by which elements are cleaned-up.
Back in the bad old days we only had 14 (or was it 16) intersection priority levels.
At least now we have 1000.
But even so we can still have building materials with exactly the same IP.
I think the logic is simply that if they are different Building Materials then one should always override the other - just as in real life.
If they are to merge they need to be the same Building Material.
For estimation (using shedules) I want to seperate the concrete blocks used in outer walls from those used in inner walls. But on floor plans they should be drawn as intersecting -> 50% interlocking units.
This can be done with the same Building Material because you have 2 different composites.
It is just a matter of searching for the composite rather than the Building Material or even by layer in the schedule criteria.
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