Booleans, Knives, and Overlap. Oh My!

Breems · 6th April 2013, 12:19 AM

Hello, all.

So, I have this friend who is a complete novice at 3d modeling/AC3D. He's trying to do a simple task - put a simple chimney on top of a slanted roof.

Here's a simple illustration:

The yellow bit is obviously the chimney and the red volume is one side of the roof (slanted).

Now, this next picture isn't for the faint of heart. Please sit down and get your kids into bed before viewing:

OVERLAP MADNESS!!!

So, I'm basically wanting to get rid of the overlap and allow the chimney to sit perfectly on top of the roof. In the end result, the bottom of the chimney should shape itself according to the top of the roof. I've tried every boolean operator and the knife tool, but nothing seems to work.

Boolean --> Union comes the closest, but it merges the two objects together, and I need them to remain separate volumes. I tried using the Knife tool and selecting the chimney as the knife while leaving the "delete knife" option unchecked and "cut away object" checked, but I wind up getting a "no surfaces to slice" error.

Am I simply using the Knife utility wrong? Should it be able to fulfill my needs?

6th April 2013, 12:19 AM	#1
Breems Junior Member Junior member Join Date: May 2012 Posts: 5	Booleans, Knives, and Overlap. Oh My! Hello, all. So, I have this friend who is a complete novice at 3d modeling/AC3D. He's trying to do a simple task - put a simple chimney on top of a slanted roof. Here's a simple illustration: The yellow bit is obviously the chimney and the red volume is one side of the roof (slanted). Now, this next picture isn't for the faint of heart. Please sit down and get your kids into bed before viewing: OVERLAP MADNESS!!! So, I'm basically wanting to get rid of the overlap and allow the chimney to sit perfectly on top of the roof. In the end result, the bottom of the chimney should shape itself according to the top of the roof. I've tried every boolean operator and the knife tool, but nothing seems to work. Boolean --> Union comes the closest, but it merges the two objects together, and I need them to remain separate volumes. I tried using the Knife tool and selecting the chimney as the knife while leaving the "delete knife" option unchecked and "cut away object" checked, but I wind up getting a "no surfaces to slice" error. Am I simply using the Knife utility wrong? Should it be able to fulfill my needs?