[vtkusers] retrieving Normal of selected cell or point on a mesh

[Chris Tsui]

Hello Sebastien and all VTK users,

Thanks for your help, Sebastien, I am able to "draw" lines or loops on 
the surface of my mesh.. :)

I was satisfied with the staircasing lines between 2 pre-selected 
points...  but not any more.. so my questions are :

1) is there any way to plot the shortest distance between 2 points while 
the line remained lying on the surface of the mesh or just to get rid of 
the staircasing?  I don't really want the polyline going along the 
boundaries of the triangles... instead I'd like it to cut through those 
triangles in order to get the shortest distance..

2)  how can I find the normal of a single selected point or cell??  and 
if that's possible to get all the normals along the shortest path 
between 2 points? 

Thanks for your help !!

Chris