[vtkusers] octree visualization example

[Francois Bertel]

Hello,

vtkHyperOctree is the class to represent a dataset as an octree.
point/cell Locators are just spatial structure to speed-up search but
there are not made to store datasets.

For example, see VTK/Graphics/Testing/Cxx/TestHyperOctreeSurfaceFilter.cxx

The source vtkHyperOctreeSampleFunction is used to create a
vtkHyperOctree dataset from a sphere implicit function.

vtkHyperOctreeSampleFunction is then plugged to a
vtkHyperOctreeSurfaceFilter to display the outer bounding box of the
octree.

ref: http://www.vtk.org/doc/nightly/html/classvtkHyperOctree.html

The other filters or source related to HyperOctree datasets are:
* vtkHyperOctreeFractalSource
* vtkHyperOctreeToUniformGridFilter
* vtkClipHyperOctree
* vtkHyperOctreeCutter
* vtkHyperOctreeDualGridContourFilter
* vtkHyperOctreeLimiter
* vtkHyperOctreeDepth
* vtkXMLHyperOctreeWriter
* vtkXMLHyperOctreeReader

Regards.

On Sun, Mar 28, 2010 at 2:03 PM, Anders Wallin
<anders.e.e.wallin at gmail.com> wrote:
> Hi group, David,
>
> Here's the kind of thing I want to do:
> http://www.youtube.com/watch?v=38LdfiMTVw0
>
> here I have created my own octree data-structure, and "by hand" I am
> drawing each of the lines for each of the cubes with a vtkLineSource.
> This becomes quite slow when there are 10 000 or more cubes(80 000
> lines!).
> I was wondering if there already are objects in VTK for doing this
> faster/better?
> At some point I am going to be interested only in the surface of my
> object, i.e. the border between the red cubes and the grey ones in the
> video. I know there are graph-algorithms for extracting these out
> there, but are there any in VTK?
>
> thanks,
> Anders
>
>
>>> Hi all,
>>> I want to represent solid (complicated) objects with an octree (which
>>> can be refined to the desired level).
>> Anders,
>> The vtkCellLocator and vtkPointLocator classes are the VTK octrees.
>> Here is an example of how to visualize it:
>> http://www.vtk.org/Wiki/VTK/Examples/PointLocatorVisualization
>> Thanks,
>>
>> David
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