[vtkusers] RE Boolean Operation on two (cube) objects

[Stephane PLOIX]

Hi Sebastian,

VTK is not a CAD tool, so you may not find exactly what you need.

The clip operation is made cell by cell.
If you have a box as input, then you have 6 cells which are the 6 faces of 
your cube. 
I think what you are looking for is an hexaedron, which is one volumic 
cubic cell.

After that, during the clip operation, the cell(s) are clipped by the 
0-level set of the field you set as input, the values being linearly 
interpolated between the vertices inside the cell.
The distance field to a cube is higly non-linear, so there is no chance 
that you will get what you are looking for.

Now you have two solutions : 
1/ dividing your input in smaller cells so that the non-linear nature of 
your clip function is not too far from the linearly interpolated one.
2/ implementing a non-linear clipping operation inside the cells.

While the second solution would be a great addition to VTK, it is also 
very difficult to implement...

Best,
Stephane




sebastian.gatzka at stud.tu-darmstadt.de 
Envoyé par : vtkusers-bounces at vtk.org
08/04/2010 11:26

A
vtkusers at vtk.org
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Objet
[vtkusers] Boolean Operation on two (cube) objects






Hello World.

I have finally manged to clip one cube with another.
The result is not what I have expected.
The intersecting cube clips one edge-point of the first cube and with it 
all the attached faces.
Look at the attached image to see how this looks like.

What I really wanted to realize was that the intersection is cut out and 
not to delete the whole sides.
It's hard to explain but a boolean operation like "substract" may descibe 
it the best - like the picture boolean.png in the attachement!

See you. Sebastian_______________________________________________
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