Full Version: Boolean Diff leaves holes in planes, not object

Hi,

Having trouble with what I thought should be simple Boolean Diff. It just leave holes in the planes, and not a in the object.




Thoughts?

Thanks,
Kevin

Image Attachments:
BikeSeat.png 

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Hi,

I'm a bit confused.

The picture you posted looks like the hole is through the object.

Frederick

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It's not. It's like a box made of planes, with a whole in the top an bottom planes. But no, like ... negative cylinder passing through.

...

Here's an interesting question. If I make cube out of straight lines. Then make each of the faces a plane. Is that a object?

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easier to understand if you post the 3dm file

it happens probably cause the transversal piece is not solid ( a missing face or a gap somewhere )

here an example

first the brown box is solid and not boolean-union with the cylinders ... boolean diff works

second the brown box is solid and boolean-union with the cylinders ... boolean diff works

third the brown box have missing faces ... the boolean diff gives holes in surfaces

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Hi Kevin,

re:
> Having trouble with what I thought should be simple Boolean Diff. It just leave holes
> in the planes, and not a in the object.

Usually that means that the base object that you are cutting is not a closed solid. The boolean commands work best on a closed solid object - that's when it can automatically determine which areas to discard and which areas to keep based on which volume they are contained inside of.

When your object is an open surface instead of a closed solid, much of that processing won't be able to be done and that's when the pieces of your cutting objects will not be left behind.

If your object is a closed solid, when you select it the object type indicator in the upper-right area of the window will say "Solid", like this:



If that says "Joined srf" or "Surface" there instead of "Solid", then that's the problem. Somewhere the object has an opening instead of having a totally closed skin.

It helps a lot to diagnose problems like this if you can attach the 3DM model file of your object with your question instead of only a screenshot.

- Michael

Image Attachments:
solid_object.jpg 

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I don't have that object type dialog in the upper right, but I'm using an older version.

I think it's obvious it isn't a closed solid. But I'm not sure how to fix it.

Maybe I need to redo the model, and be more careful constructing it out of solids, instead of building-up parts of it from surfaces.

-Kevin

Attachments:
BikeSeat.3dm

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you need to build missing faces ( with networks )

copy paste the 2 circles ( to trim later )

I delete the two faces with circles ... select the four borders ( don't forget to join the segments of each border ) and apply Planar ( to prevent possible gaps )

join the 6 faces of the piece ( it says Solid ... good for booleans

paste + trim the circles and the flat faces ( then you can delete the round disks )

and loft between the two circles

finally copy all faces included the round surface ( the loft ) and paste elsewhere ... then join to have a solid

( I work on the half piece and do a mirror + boolean union )

3dm file joined

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Thanks, this is helpful. I will try to repro the repair steps, and keep things as object in my workflow.

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