[vtk-developers] [VTK 0013252]: vtkPicker tolerance inaccurate

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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http://vtk.org/Bug/view.php?id=13252 
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Reported By:                Clinton Stimpson
Assigned To:                
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Project:                    VTK
Issue ID:                   13252
Category:                   (No Category)
Reproducibility:            have not tried
Severity:                   minor
Priority:                   normal
Status:                     backlog
Project:                    TBD 
Type:                       incorrect functionality 
Resolution:                 open
Fixed in Version:           
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Date Submitted:             2012-06-19 22:20 EDT
Last Modified:              2012-06-19 22:20 EDT
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Summary:                    vtkPicker tolerance inaccurate
Description: 
vtkPicker's tolerance isn't really a fraction of the window size.
A specified 1% screen tolerance in some cases can actually result in a 50%
screen tolerance which makes it very inaccurate and unusable.  This occurs more
frequently when trying to pick small features on a large dataset.

See attached script for an example.
The camera position and the geometry (approximately unit sized) remain fixed
relative to each other.  The script adjusts the focal point to be near and far
and demonstrates the incorrect scaling of the pick tolerance.

I think its a flaw for vtkPicker to assume it can scale the tolerance once and
apply that scale through all datasets in the session.  There's also the possible
issue of one dataset with a large span in the camera's Z direction, where the
tolerance at one end shouldn't be the same as the tolerance at the other end.

This is probably not an issue with parallel projection.
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Issue History 
Date Modified    Username       Field                    Change               
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2012-06-19 22:20 Clinton StimpsonNew Issue                                    
2012-06-19 22:20 Clinton StimpsonFile Added: testpick.py                      
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