Problems with Booleans, help!

I just spent the past hour trying to figure out how to get this to work, and in the process, have gotten a headache as the only answer :spin:

Now I need some expert help!

In my scene I have a hanger bay built underground, but the hanger bay also has a guest: A stream of lava that goes through the bays bottom floors and out two exits, the base ‘mines’ this stream to provide extra power. Anyway, I modeled the stream and am now trying to use a boolean to slice into the floor so I can model the river banks itself, but whenever I try to use the boolean to do this it only creates a small part of the stream and nothing else.

The stream is winding, meaning it’s pretty curved so I’m wondering if the curvyness of the stream is causing this issue.


I dunno, I don’t really understand the picture right now, maybe a different angle or a small chunk of the .blend file would help. Blender’s booleans are notoriously buggy right now, though, you’d be better off modelling it yourself. If you do, there are some useful tools that would help you, like the knife cut tool (ctrl+K) and the bevel tool (it opens from the ‘face’ menu (ctrl+F, or ‘face’ in the mesh menu in the 3d viewport. it’s in the face menu, but it works on edges and vertices too). The sculpt tool would also help a tonne, once you have the basic modelling down.

Any idea’s on tutorials for the sculpting tool?

Hello Kalshion

Re Booleans : I used to have big difficulties with Booleans. But now I think I have cracked it.

I’ll show you examples with simple objects - you should be able to follow along with your more complex meshes :

Red Cube & Green Cylinder - Seperate Meshes.

Objects modelled individually - Red Cube & Green Cylinder.

Position the objects in the correct positions


I tend to select the object that is being cut first, then the “cutter”.

So in Object mode, select the Red Cube first, then hold shift , and select the Green Cylinder.

Next select Boolean Operations from the object menu, then the particular type of Boolean required.

Now this is the part that confuses most people.

Boolean Operations creates a NEW object at the same location as the 2 chosen objects. The problem is that Blender makes no indication of this - and it’s often quite easy to assume that nothing has happened.

So what you need to do is straightaway after hitting your chosen Boolean operation, press (G) to Grab and just move the existing selection out of the way. What you are doing here is moving the original “cutter” mesh and the original mesh being cut out of the way: .

TA-DAAAAAA - you are left with the resultant Boolean Mesh. Easy Eh ?

Now all there is to do is to delete the original meshes.

All of the Boolean Operations work in the same way :

UNION - the resultant mesh is a single mesh copy of the originals.

- the resultant mesh is the difference between the meshes :

Does that help in any way ?

I know that Booleans can be problematic. Try doing the above with smoothed objects - not really brilliant.

Sometimes faces get lost somehow, don’t ask me why I don’t know but it’s worth doing a quick render to check.

Big Bear Is a pretty nice intro tutorial. Try that and see how it fits you.

good description big bear!