[vtkusers] How to project a polyline to terrain that represented by TIN?

[hellow]

How to project a polyline to terrain that represented by TIN (triangulate irregular network)? I have a 2D polyline and a TIN, and I want to get all Z value of points that recursive subdivision of the polyline by TIN, how to do?
 
I currently solve it as follows:
1. along polyline, resample to get many points.
2. probe these points' Z value on TIN with it's scalars (height).
3. using vtkDecimatePolylineFilter to reduce number of points.
 
This method is very slowly when polyline is more longer and TIN is more bigger. So I want someone to help to get another solution.
 
thanks.
 
                                               Liang Aibin
                                               lab_zj at 163.com
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