I’ve just put in Blender 2.90.1 and was previously using 2.83.1 on an iMac using 10.14.3.
Often I have no problem at all using a boolean modifier, but sometimes it’s a mess and doesn’t behave like it should.
When I’ve done tests and it works, I did this:
- Created a sphere mesh
- Created a cube mesh
- Set the cube mesh to show as wire frame so I could see what was going on.
- Move the cube to intersect with the sphere
- Selected the sphere
- Added a boolean modifier
- Used the eyedropper tool to pick the cube as the modifier
- Tested the 3 options (Difference, Union, Intersection)
When I do that, it works perfectly.
I need to do the same with a post (this is part of a deck design). So I do the above, but add steps:
- Create a cube mesh
- Rename cube mesh to TestPost
- Transform TestPost to make it 12’ high and 7.5" x 7.5"
3a. Use CTRL-A to apply changes so that the scale is still 1 in every dimension. (I label this “3a” because I’ve done this in some tests, not in others. It doesn’t seem to make a difference.)
- Translate TestPost to a spot far enough from my main project the other objects won’t be near it or show in screenshots.
- Create a cube mesh
- Rename new cube mesh to ModCube
- Transform ModCube to make it 11.25" high and 4.5" wide (Y axis) and leave the X size the same
7a. Use CTRL-A to set scale back to 1 (done in some tests, not in others - makes no difference)
- Modify ModCube so I see it as a wire mesh so I can see what’s going on.
- Translate ModCube so it fits in the notch I want to make in TestPost
- Select TestPost and Add Modifer (specify boolean)
- Use eyedropper tool to pick ModCube as modifier.
At this point I have troubles. The Boolean Modifier option (or mode or whatever) defaults to Difference. Once I pick ModCube as the modifier, this is what I see (with Difference selected):
(And, yes, MdCube is set to show as a mesh, but Difference is acting like Union.)
This is my first post, so I can’t include another image (mods - if you let me, I’ll edit and add the other two images. For Intersect, ModCube is all gray, as if it’s the output.
For Union, only TestPost, and ALL of TestPost is the output.
So Intersect and Union gives me an output I shouldn’t get for any of the 3 operations and Difference gives me what I should get for Union.
Also, those extra edges you see on TestPost show up as soon as I select ModCube as the modifier to use.
From what I see, the difference is that I transform TestPost and ModCube, both, and resized them. I don’t do that with my other test objects. I thought it might be an issue with their scale, so that’s why I tested them with and without resetting their scales.
What do I need to do to make this work?