Boolean -> Difference delets whole polygon?
 

HI. I'm trying to cut out a window for a house. The house is a polygon cube with some divided lines that i extruded to make a bay window.

I have tried selecting the house first then the window, and hte window then the house, and click boolean->difference but every time it deletes the whole house.

Wierd thing is, i have a version of the house just before i extruded all the bay windows and it works fine with that one (it's just a cube). In the new one i divided it loads and just added more edges. But I 'm not sure what i have done to cause this problem.

Anyone have any ideas?

run a search in this forum with 'booleans disappear'
You should hit a few dozens at least...
You can find it n FAQs as well
Benny

show us a picture, ill be glad to help ...

i love booleans ... lol! :p

Ok turns out there was a secret hole in my cube under the roof so i couldn't see it.

so i managed to get one window sorted. then i copied the polygon i used, and select the face on the bottom and extruded it to make the window taller.

Then when i try to do the same boolean difference (on the same polygon) i get the window but also some odd black artifacts around it (like someone literally punched a whole in the wall).

what causes these?

I've attached a pic of it.

either because you have multiple faces on there (which probably isn't the case for you)

most likely its because your faces aren't planer (flat along one axis)

solve this by drawing more edges

faces should be kept to 4 or 3 sided polygons where possible

OK i don't know what was wrong with it but I used "set to face" and it fixed it.

Now i'm having more issues with the same face. I've got the windows and now i want to draw a horizontal edge at the base of each window for a window sill (that spans across the walls as well).

So i used the split polygon tool to draw more edges, turn snap to curve on. and i can draw the line ok, but when i press enter it covers up some windows. (i.e. the window indent is still there, it's just covered up by a face in front of it).

I don't understand where this face comes from when i only add an edge.

I've added a pic of the problem. THe orange edge is the one i've just added, and it's caused two windows to be "covered".

EDIT: ok i've played around some more, and the same thing happens if i cut the face in half. i'm guessing when i split polygon i'm doing the same thing.

try delete all history

the reason why the new faces keep appearing is because the window isn't connected to the outer edge/box. all vertex's need to be connecting to something. Booleans are abit of a pain when you work with cyclinders with lots of vertices.

http://img525.imageshack.us/img525/1564/newfacerl1.jpg

the reason why that wierd line is happening is because there are extra vertices which are not needed and creating stretch in your mesh. you may need to move some vertex's as they will be hiding underneath each other

http://img374.imageshack.us/img374/2...exlinesvi2.jpg

hope this helps abit