Can't do Boolean Operation???

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Can't do Boolean Operation??? // Tech Forum

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Post by DesignDevil // Nov 18, 2008, 11:27pm

Total Posts: 76
Hi everybody, TS6.6 is driving me crazy ;)

i have a cube and a lowpoly house model (see image). I try to substract the cube from the house but it doesn't work.

I tried everything, to increase 'Identity', to decrease 'Identity', to change the cube size and/or the position, change the 'on fly offset' - nothing will work.

I always get the message "Can't do Boolean Operation. Change the relative positions of the objects or change the boolean precision.'

Please help me - i go crazy.

Post by Mr. 3d // Nov 19, 2008, 12:37am

Mr. 3d
Total Posts: 747
Here's a start:


Post by DesignDevil // Nov 19, 2008, 12:46am

Total Posts: 76
Well, thanks to you, but:

First: I have TS6.6 !

Second: I know how i have to do it. The thing is that TS will not do it !

Anyway, i think i have found a solution. I saved the house model as OBJ with the LUUV Plugin. LUUV means that there are holes in the model and it must be triangulated.

I pressed yes ! Erase the old model.

Then i load the OBJ model and substracted a cube from this ( the cube does not attache the model himself !!! ). Thrue this it erases the triangulation. After that the model is "cleaned" and now i can substract my cube so how i wanted.

Maybe this works without saving it - i don't have tested it.

Post by Mr. 3d // Nov 19, 2008, 1:15am

Mr. 3d
Total Posts: 747
: ( the cube does not attache the model himself !!! ). Thrue this it erases the triangulation. After that the model is "cleaned" and now i can substract my cube so how i wanted.

That's the key: The objects must be separate entities. The object to be subtracted from must be selected (as shown in the diagram).

Maybe this thread can help others !:)

Post by TomG // Nov 19, 2008, 2:27am

Total Posts: 3397
Booleans are trickier than they seem in terms of the math involved. The new booleans in tS7.6 on the workspace side are much better - they are more stable, more likely to work, more likely to give the expected result, and as an added bonus they have history if you enable it so you can move or rescale the subtracted cube in this case AFTER doing the subtraction, or even change the subtraction to an addition, etc.

Getting them to work in 6.6 when they don't want to can be tricky. Adding more edges in a face can help, giving it more to work with - but then again removing edges from a face can sometimes help, by creating less overlaps and complexity.

Ensuring no faces are directly lined up usually helps - eg if the bottom face of a cube aligned with the bottom face of the house, then it might give problems.

Adjusting those two values could sometimes help, but I never did find a systematic way of doing it, I just had to guess them randomly and see if it helped!

There are always dangers with booleans also including "floating vertices", people often talk of the "evils" of booleans. In tS7.6, drawing the required face for a window or door, then sweeping in Boolean mode, is often better than doing a regular boolean - but you still have to watch those unconnected floating vertices especially if you plan on exporting eg to Virtual Earth or similar.


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