Boolean using Plane vs Cube

I’ve been using a mesh cube to perform boolean operations on my target mesh to shape it basically slicing away its sides an an angle, to produce a faceted shape. Everyone knows boolean can get messy generating extra lines and vertices everywhere like a spider web.

I just tried doing the same using a mesh plane (with one edge vertex snap pivoted to the grid so i can control rotation angles) instead to cut away from my target mesh like a knife. I’m finding it does a much cleaner job than doing boolean with a cube. You still have to clean up afterwards by merging vertices, removing doubles, and joining faces, but not as much as before. Does anyone else see the same result when comparing boolean results using a plane vs a cube?

I know in many cases you can’t always use a plane to cut with if you want to make a complex multisided boolean to carve away at another mesh. I’m just trying to find the best way to have a “cutting plane” tool to slice a side off another mesh with.

I’m reading about the knife tool included with Blender. But it seems you sort of have to eye it up or select midpoints etc. But I need a cutting plane that can be snap pivoted on the grid and set to precise angles like with the N-key rotation settings so i’m using a mesh plane to kind of do this. Is there an existing tool or script than can do what I require?.

I tried the Megabool script using a cube and it seemed like it was performing the operation backward on the first mesh I selected instead of the second as the target? I even got a script error doing a boolean difference. I didn’t try it yet using a mesh plane to slice with. I’m using Blender v2.45 so maybe there are some compatibility issues with the script.

Never mind, it seems the shape of the target mesh is a big determining factor on how much break up you get.

If you have set up a plane as a cutting reference, you can snap the knife tool to the planes vertices using Ctrl-LMB.
The Plane must be part of the same mesh that you want to cut.

^^^ Do you mean the built-in knife tool or the add-on kinfe Python script? I thought the built in one is just for cutting faces, etc.

The built in knife tool can be snapped to vertices to allow precise cuts from known points (Ctrl-LMB). The Knife Tool python script is an Object based script that uses a different Object (Plane) to cut vertices through your object and affects all edges that an infinite plane crosses.