[vtkusers] Re:Distance between polydata and a point cloud

[Cedric]

Hi,

I'm not sure to understand what you really want in your first point  
I'll only answer your second one :
You are right to use the vtkPointLocator to find the nearest point.  
You should also have a look to the vtkKdTree class. It performs a  
quickier search for the nearest point. But if you don't have so many  
points vtkPointLocator is ok.

You can of course use your distance information to color your  
polydata surface. You have to choose a rule to transform your  
distance in R,G,B values (the rule depends on which colors you are  
looking for) and then use it as the scalar values of the polydata  
(exemple bellow).

color = vtkUnsignedCharArray::New()
for (i=0,...,number_of_points-1)
	color->InsertTuples3(i,R,G,B)
polydata->GetPointData()->SetScalars(color)

Regards,

Cedric Schwartz


I'm looking to do two things; first I'd like to measure the average  
distance between each point in a point cloud, and the polydata  
surface it is registered to.  I used the 	 
vtkIterativeClosestPointTransform if that helps at all.  The second  
thing I would like to do is measure the distance between each point  
in a polydata surface and the nearest point in the point cloud.  From  
reading the user's list archives, I imagine I might use  
vtkPointLocator or vtkCellLocator, with FindClosestPoint, but I am  
not sure.
I also wonder if it would be possible to use that information to  
color-code the polydata object's surface (like a 'hot' or 'cold'  
color scale) to better visualize a correlation between points and a  
surface.

Jason Taclas
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