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<DIV><FONT face=Arial size=2>gradient vectors of iso-surface at each point, if I
use vtk to generate iso-surface into 3D triangle mesh surface.</FONT></DIV>
<DIV> </DIV>
<DIV>Best
Wishes,<BR>-----------------------------------------------------------------<BR>Dongqing
Chen<BR>Ph.D Research Assistant<BR>Rm. 07, Paul C. Lutz Hall<BR>Computer Vision
& Image Processing (CVIP) Lab<BR>Department of Electrical & Computer
Engineering<BR>Speed School of Engineering<BR>University of
Louisville<BR>Louisville, KY. 40292<BR>U.S.A<BR>Email: <A
href="mailto:dqchen@cvip.louisville.edu">dqchen@cvip.louisville.edu</A><BR>Phone:+1-502-852-2789
(Lab)<BR>
+1-502-852-6130
(Office)<BR>-----------------------------------------------------------------</DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=dqchen@cairo.spd.louisville.edu
href="mailto:dqchen@cairo.spd.louisville.edu">Dongqing Chen</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=vtkusers@vtk.org
href="mailto:vtkusers@vtk.org">vtkusers@vtk.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, July 15, 2006 2:02
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [vtkusers] can I use normals to
evaluate the gradients?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Dear All:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> 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:</FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face=Arial
size=2></FONT></FONT> </DIV>
<DIV><FONT face=Arial
size=2>*************************************************************************************************</FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face="Times New Roman"
size=3>Triangle meshes are piece-wise linear approximation of smooth manifold.<BR>the so-called gradient is not well-defined. you can use any reasonable<BR>approximation from the gradient (normal) of the incident faces.</FONT><BR>**************************************************************************************************</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> 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?</DIV></FONT>
<DIV><FONT face=Arial size=2> </DIV></FONT>
<DIV><FONT face=Arial size=2>Best
Wishes,<BR>-----------------------------------------------------------------<BR>Dongqing
Chen<BR>Ph.D Research Assistant<BR>Rm. 07, Paul C. Lutz Hall<BR>Computer
Vision & Image Processing (CVIP) Lab<BR>Department of Electrical &
Computer Engineering<BR>Speed School of Engineering<BR>University of
Louisville<BR>Louisville, KY. 40292<BR>U.S.A<BR>Email: <A
href="mailto:dqchen@cvip.louisville.edu">dqchen@cvip.louisville.edu</A><BR>Phone:+1-502-852-2789
(Lab)<BR>
+1-502-852-6130
(Office)<BR>-----------------------------------------------------------------</FONT></DIV>
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