[vtkusers] vtkCellLocator bug !! new year edition, seems that it is an old bug

[sebastien MARAUX]

Hello, I posted a message during christmas holidays
about a vtkCellLocator bug but didn't receive any
answer (well everybody got the right to 
take some holidays, right).

I post it again : 

I can send a code snip if needed (see also mailing list archive)

I am using vtkCellLocator, and specifically
IntersectWithLine() method, to retrieve height of a 
surface from an (x,y) couple : I send a Line
from -FLT_MAX (in c++) to +FLT_MAX for (x,y)
couple and retrieve z of resulting intersection point.
This gives sometimes good results,
 but also sometimes bad ones.

You can see on the picture that mi elevatino model is regularly
triangulated (DEM_data), but the polygon_data mapped on it
gets some wierd up and down effects, because of 6 or 7 points 
which height has been badly retrieved (always > than real height).

You don't see it here but other points map perfectly the
DEM.

Thank you to help me fix this, I think it would be very valuable
to correct such a bug.

Sebastien MARAUX


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