How to use the knife-function in 2D-Polygons

[rdeutsch]

Hi

I'm here the first time and want to say hello. I use the AC3D to build sceneries for modelflightsimulators.

But now i have a problem:
I have a polygon and 3 small polygons inside.



Now i need to cut out the regions of the 3 small polygons.
Can anyone explain me how i can do that with the "knife"-function or are there other ways?

Thanks and best regards
Robert

[Andy]

Welcome Robert.

There are usually many ways to make the same stuff.

Try making a 3x7 mesh and deleting the 3 surfaces.

[rdeutsch]

Hi Andy

Sorry, but how can i make a 3x7 mesh?

Regards
Robert

[luuckyy]

Hi rdeutsch,
this is what Andy is talking about :



You will have a black and white mesh just after its creation.
It's just 2 different materials applied to the mesh.
If you want a single material for the whole mesh then just select all the surfaces and apply a single material
to them (#1 in my case).

Regards.

[rdeutsch]

Hi luuckyy and Andy

I tried that but the result is not very impressive.

I can use the knife-function only when the knife-object is a 3D-model, as a 2D-polyon it doesn't cut anything.
So here are the steps i made with the 3D-polygon, but as you can see, the knife does not cut all parts:





Do i something wrong or is there another way?

Thanks and regards
Robert

[Dennis]

I think Andy's original suggestion was to create the 3x7 mesh and skip the knife altogether. This is probably the best approach for what you're trying to do (the knife isn't built to cut out interiors, only make slices along edges).

The idea is, you would remove the surfaces you didn't need from the 3x7 mesh. You could then resize each of the rectangular holes by manipulating the vertices directly.