Hi I have these few corner pieces that will not boolean union but others like it have boolean unioned. Its just a few of them (like 5) that will not do it. Here is the piece
Nevermind I fixed it
If you know how you fixed it maybe write it out as a reply here, it could help other users… 
So I took another piece that was similar but on a different side and just turned it around. I don’t know why that mattered but it worked. Maybe because that was originally from a different side or something.
Duplicate topic
no its not duplicate. topic its brand new
Bit very similar topic like your other problems. Have you gone through any tutorials?
Yes I have. I was in school for industrial design and that’s where I learned this. Please help if you can