[vtk-developers] Incremental Point Locators

[David Gobbi]

You could map the coordinates through a function that maps all
space into a finite space, e.g. the following function is smooth
and maps [-inf,+inf] to the range [-2,+2]:

if x < -1: y = -2 - 1/x
if -1 <= x <= +1: y = x
if +1 < x: y = 2 - 1/x

You'd use the above function to decide what bin to use for each
point.  The points would still be stored as-is.

 - David


On Sat, Oct 6, 2012 at 7:35 AM, Robert Michael O'Bara
<bob.obara at kitware.com> wrote:
> That's along the lines I was thinking about.  The octree could have an "octant" of points that are outside of the tree's bounds.  When the number of points exceed the octant limit the tree could be expanded to include the new bounds and the points in the outside octant inserted into the expanded tree.  I don't think that the resulting tree would have any more resolution problems that an octree that started with the final bounds.
>
> Bob
>
> Sent from my iPad
>
> On Oct 6, 2012, at 9:13 AM, David Thompson <david.thompson at kitware.com> wrote:
>
>>> The last I checked, no. The implication of unbounded locators is that they can span all space, which tends to introduce resolution problems very quickly :-)
>>
>> The approach I've seen is to use octrees which can be grafted to a new parent node when their bounds need to be enlarged. Unfortunately, I haven't seen it in VTK. :-(
>>
>>    David
>>
>>> On Fri, Oct 5, 2012 at 11:00 PM, Robert Michael O'Bara <bob.obara at kitware.com> wrote:
>>> Hi All,
>>>
>>> Are there any incremental point locators in VTK that don't require the need to know the largest possible bounds of the points?  The use case I'm dealing with involves a set of points that can be extended to dynamically.
>>>
>>> Thanks in advance for your time and help.
>>>
>>> Bob
>>>
>>> Robert M. O'Bara, MEng.
>>> Technical Leader
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