[vtkusers] can I use normals to evaluate the gradients?

[Dominik Szczerba]

gradient of what?
--ds

Dongqing Chen wrote:
> Dear All:
>  
>    I am trying to get the gradient vectors of all the vertices of 
> triangle surface mesh. One of my friend gave me some advice list as below:
>  
> *************************************************************************************************
> Triangle meshes are piece-wise linear approximation of smooth manifold.
> the so-called gradient is not well-defined. you can use any reasonable
> approximation from the gradient (normal) of the incident faces.
> **************************************************************************************************
>  
>   Can I just simply use to vtkPolydataNormals to get all the normal 
> vectors? Then how can I relate the normal vectors with the gradient 
> vectors at the points?
>  
> Best Wishes,
> -----------------------------------------------------------------
> Dongqing Chen
> Ph.D Research Assistant
> Rm. 07, Paul C. Lutz Hall
> Computer Vision & Image Processing (CVIP) Lab
> Department of Electrical & Computer Engineering
> Speed School of Engineering
> University of Louisville
> Louisville, KY. 40292
> U.S.A
> Email: dqchen at cvip.louisville.edu <mailto:dqchen at cvip.louisville.edu>
> Phone:+1-502-852-2789 (Lab)
>             +1-502-852-6130 (Office)
> -----------------------------------------------------------------
> 
> 
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-- 
Dominik Szczerba, Ph.D.
Computer Vision Lab CH-8092 Zurich
http://www.vision.ee.ethz.ch/~domi