[vtkusers] VTKboolean smoothes the results! Any other libraries for boolean operation on polydata?

[Majid Mohammad sadeghi]

Dear Cory,
As I applied vtkPolyDataNormals to the polydata before the boolean operation I got the smoothed object, so you were right. But I dont understand exactly what is happening here? Since the geometry dimentions are very important for my application, Can I have the noisy version? Is there any way I do not get it smoothed?
Thanks,




On Monday, July 17, 2017, 6:48:58 PM GMT+3, Cory Quammen <cory.quammen at kitware.com> wrote:

There shouldn't be any geometry smoothing going on in this filter. Can you verify that the geometry has changed in the smoothed version?
This is speculation, but one possibility is that the surface normals in your original surface come from a gradient computation in the volume from which the surface was extracted and noise in the volume result in the bumpy appearance. You can check this by applying the vtkPolyDataNormals filter to your original surface and looking at the result.
HTH,Cory
On Mon, Jul 17, 2017 at 10:21 AM, Majid Mohammad sadeghi <majid.msadeghi at yahoo.com> wrote:

Dear Cory,
Thanks for the reply, I set the actors property to  SetInterpolationToFlat(); as you said, but the result is the same I put a picture before and after boolean operation here. Any suggestion? Are you familier with any other library? Current boolean operation takes about 150 seconds on my system, do you think this is normal?






On Monday, July 17, 2017, 6:00:50 PM GMT+3, Cory Quammen <cory.quammen at kitware.com> wrote:

What do you mean by smooth? The lighting is smooth? I think the filter
may be adding surface normals, in which case any actor for the data
will turn on Gouraud shading (or maybe Phong) by default, which will
make your surface look smooth. You can turn off smooth lighting as
shown in this example:

http://www.vtk.org/Wiki/VTK/ Examples/Cxx/Visualization/ FlatShading

On Mon, Jul 17, 2017 at 9:49 AM, Majid Mohammad sadeghi via vtkusers
<vtkusers at vtk.org> wrote:
> Hi everyone,
>
> I am using vtkBooleanOperationPolyDataFil ter, and it works fine except after
> the operation it smoothes the polydata, which I dont want. Is there a way to
> stop that? Or is there another library for boolean operations on polydata?
>
> Thanks.
>
>
> ______________________________ _________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/ opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_ FAQ
>
> Search the list archives at: http://markmail.org/search/?q= vtkusers
>
> Follow this link to subscribe/unsubscribe:
> http://public.kitware.com/ mailman/listinfo/vtkusers
>



-- 
Cory Quammen
Staff R&D Engineer
Kitware, Inc.




-- 
Cory Quammen
Staff R&D Engineer
Kitware, Inc.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20170717/fdf85822/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Untitled-8.jpg
Type: image/jpeg
Size: 261587 bytes
Desc: not available
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20170717/fdf85822/attachment-0001.jpg>