Subtract a tube from a wall

[cpot]

Hello,

Sorry to ask so many questions, but the trial will not last long.

I want to cut a hole in the wall or at least make segments from the intersect of the tube and the wall.

I understood that the tube and the wall must be an 'Object', selecting all surface was not enough to do boolean operations. I created then 2 objects.

Then as one is not a closed object (wall), i have been advised to use "knife" which i did.

Then i go the second screenshot, not exactly what i expected :-)

Best,
Chris

[Andy]

There are many requirements for booleans to work correctly. Both objects must be fully enclosed 3D shapes with no holes, and all normals facing outwards. After hearing that you had to remove so many duplicate vertices, I suspect the main shape is not perfect for this.


Try selecting Tools->select-leaky surfaces and seeing if anything is selected. It may be too much to fix so I'd suggest making the shape you want and moving that into position to replace the 'wall' where you want the hole area.

[cpot]

Originally Posted by Andy

There are many requirements for booleans to work correctly. Both objects must be fully enclosed 3D shapes with no holes, and all normals facing outwards. After hearing that you had to remove so many duplicate vertices, I suspect the main shape is not perfect for this.


Try selecting Tools->select-leaky surfaces and seeing if anything is selected. It may be too much to fix so I'd suggest making the shape you want and moving that into position to replace the 'wall' where you want the hole area.

you are right ... 2026 surfaces with leaky edges (which means?) ... it means that a lot of functionalities will not work ? is there a rather quick fix ?

Will all my X-plane sketchup .obj export when ac3d re-imported will be the same ?

Best,
Chris

[Andy]

I can't say for sure, but it's possible that the stuff coming out of Sketchup is not perfectly optimized for use elsewhere.

Leaky means that you have holes or open edges e.g. polygons that are close to each other but their vertices aren't shared. Modeling with a leaky object is fine, unless you want to use Booleans (Booleans need 'solid' objects).

If the object you have looks like it should be non-leaky i.e. no obvious holes, you might try this:

Object->Optmize-vertices
Object->Optimize-surfaces

Then try Tools->Select-leaky-surfaces. If it says you have holes, you could try Object->fill-holes.

You can quickly check for normals being oriented by selecting everything and setting it to single sided ("1S" button). If you look around and see any holes, some surfaces are facing the wrong way. Surface->Unify-normals can fix this.

It all depends what the initial model is like.

[cpot]

Originally Posted by Andy

I can't say for sure, but it's possible that the stuff coming out of Sketchup is not perfectly optimized for use elsewhere.

Leaky means that you have holes or open edges e.g. polygons that are close to each other but their vertices aren't shared. Modeling with a leaky object is fine, unless you want to use Booleans (Booleans need 'solid' objects).

If the object you have looks like it should be non-leaky i.e. no obvious holes, you might try this:

Object->Optmize-vertices
Object->Optimize-surfaces

Then try Tools->Select-leaky-surfaces. If it says you have holes, you could try Object->fill-holes.

You can quickly check for normals being oriented by selecting everything and setting it to single sided ("1S" button). If you look around and see any holes, some surfaces are facing the wrong way. Surface->Unify-normals can fix this.

It all depends what the initial model is like.

I am currently in a business trip but i will as soon as i come back. I join attached the ac file if some interest for you

Best,
Chris

[cpot]

Hi,

I tried all your suggestions without success.

Therefore i tried to simplify the problem by creating a tube and 'knife' it in a single surface of the wall. i obtained the attached result (not a hole in the wall)

Did i do something wrong ?

Best
Chris