Over here it seems to work, can you try it again and see if it works for you now?

You may have run into a different bug, where an object can get slightly messed up in a way that interferes with booleans, but which is fixed if you save the file and re-open it. That's why it may work now.

Please let me know if it does not work for you after reloading the file.


> And how can I select subsurfaces that object contains? (I bet I have to use
> hot key or combination of certain key and mouse :) )

Have you seen how to select edges of an object? I mean after you do an initial click on an object, a second click on it will select an edge.

In the same way, you can also use a second click on an object to select a sub-surface as well. But you have to click somewhere that is not nearby an edge, because edges have priority. It often times helps a lot to zoom in a little bit so that the surface you want to select is larger on the screen so that you have an easier spot to click on it that is not close to an edge.

Eventually there will be some additional selection-filter tools that you will be able to set to have more control over what you are selecting.

Please let me know if this isn't clear.

- Michael