I did a boolean Union and got an exlamation point dot stating a surcae intersection error
When checking the point reveils the bottom surface mesh seems to have an issue
There is a very thin surface between the two sufaces:
I extracted the 3 surfaces duplicated the 4 main edges and joined them into 2 cuves.
Next I lofted the 2 curves and joined the resulting surface to the main part.
A boolean between the 2 was now possible:
As for the bottom and middle part, both have surfaces already parrtially split at the intersection with the bottom part:
I extracted the subsurfaces and duplacated edges to trim the overlapping parts from both parts:
The bottom part again had a trailing thin surface I deleted:
After joining all, there was still an open edge:
zoomin in reveald the top surface to not be trimmed correctly.
I extracted the surface
and duplicated the curved edges, joined them and made a loft:
joining that to the rest made a polysurface with yet another tiny open edge:
And unfortunately I need to stop here because I have an appointment
I hope the steps will help in fixing the other issue.
Boolean - Split Join IssueWD.3dm (774.1 KB)