[vtkusers] Implicit Modeling

David.Pont at ForestResearch.co.nz David.Pont at ForestResearch.co.nz
Mon Sep 2 18:06:25 EDT 2002

  vtkImplicitModeller just computes the Euclidean distance to the input
geometry, so points 'inside' and 'outside' are all positive. Interestingly
it uses vtkCell->EvaluatePosition which returns inside or outside (1 or 0)
but does not use this return value, so if you wanted to make an amended
class you could get this behaviour...
I am not familiar with STL data but if it is polydata I can send you a C++
class to treat this as an implicit surface, with inside/outside determined
by the surface normals. Let me know if you want it.


|        |          "Tushar Udeshi"        |
|        |          <tudeshi at zyvex.com>    |
|        |          Sent by:               |
|        |          vtkusers-admin at public.k|
|        |          itware.com             |
|        |                                 |
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|        |          03/09/2002 03:16       |
|        |                                 |
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  |      To:     <vtkusers at public.kitware.com>                                                                 |
  |      cc:                                                                                                   |
  |      Subject:     [vtkusers] Implicit Modeling                                                             |

Hello vtk users.
When I connect a vtkImplictModeller to the output of an STL reader, I
seem to be getting only positive values. Is it possible to get negative
values for voxels inside the solid object and positive for outside? If
it is not possible for STL data, it is possible for any other data type?

Thanks for you time,

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