I get this problem quite a bit with boolean merging. I’ve created a model from several pieces and I want to boolean UNION them together as one shape.
My reason for liking UNION is because if I use JOIN then intercepting shapes end up keeping their overlapping areas as mesh and I think that’s going to be messy in the long run (waste of virtual space). UNION is good because when it works, I only get the outer shell of the combined form.
What you see here are two linking shapes (I deleted everything else in my real model to give a simple example). When I try to perform boolean UNION on them, I end up with something more like DIFFERENCE (where one object gets subtracted from the other instead of combined). Why is it doing this? I have tried recalculating normals (worked last time I had something similar) but it’s still messing up. What should I do to fix it?
To download the blender file and have a go at it yourself, go to http://tinyurl.com/a3ob3 and click the hyperlink “Click here to download” (file name is “problem.blend”).