Hi Ditto - this model will be difficult to boolean well because you've got a lot of pieces that are just kind of barely skimming and nearly overlapping with each other but not quite exactly overlapping.

Here's an example of one area:



Zooming in closely there:



So note there that the pieces that the outer edges of the pieces that you're trying to boolean come really quite close to each other but are not quite exactly aligned - that kind of situation is difficult for the booleans to handle. In some areas they may try to form a small slivery fragment there and maybe in other spots they may try to treat those edges as coincident.

To get better results you want to have such things either have more clearance between them or be more exactly aligned on top of each other rather than coming about this far away but not quite exact.


... After a bit more of a look - the boolean union will actually succeed in MoI if you do it just 2 pieces at a time instead of all at once. But the result has little tiny slivery pieces in it because of that inexact matchup between the parts.

- Michael