I have many closed mesh small blocks, and I need to subtract the two large blocks from the Boolean difference. Most of the results are normal, but some parts appear completely incomprehensible. I have been trying many different ways to BooleanDifference, but there are still unpredictable results. Does anyone one know what could be solving this problem? Thanks so much for the help in advance!

Large Volume Boolean Difference Operation.3dm (1.4 MB)

your geometry is in outer orbit

try moving everything close to world 0,0,0

also, if a mesh/brep is fully enclosed in a volume you are trying to subtract with, it won’t work.

Booleans need an intersection.

and then there are some strange very thin meshes in your file that, I believe are out of tolerance of your file units settings. (you have a coarse resolution of only 1cm )

there is also some strange welding on the meshes, but I don’t think that affects the booleans…

@Lingmao not sure if this helps, but if you have access to the WIP, you can ShrinkWrap both and then do the Boolean Difference:

Thank you very much for your valuable advice!

I tried again as you suggested, but the result is still not very good.

Other instructions:The following mesh body is generated from a point cloud using the Delaunay algorithm. Some shapes are indeed deformed, but this is difficult to control.

Thanks again!

Boolean operation result.3dm (2.6 MB)

That’s a great idea!

This is the best result I have seen so far! “However, the attributes and organizational form of the grid body below cannot be changed, otherwise there may be a certain gap in the results of my final requirements. Anyway, thank you very much for your proposal.”