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thanhnt
05-18-2002, 05:11 PM
Hi all,

I am OpenGL beginner but I visit this forum to get some advises.
My problem is:
I have a xyz points set from contour map and I would like to render them in 3D using OpenGL.
I have ever heard about TIN (Triangled Interpolation Network, DEM, DTM, ...) but I do know which I should follow, now I do not know how to do with my problem.
Please, help me?

lobstah
05-18-2002, 07:49 PM
TIN: Triangluated Irregular Network, i.e. points are irregularly spaced.

Deal with regularly space points first (grid), then go for the TIN.

Have Fun! http://www.opengl.org/discussion_boards/ubb/smile.gif

lobstah...

Chromebender
05-21-2002, 06:47 AM
Yes, try a regular grid of triangle (strips) for your first program, then when you start using TINs, you might read about Delauney triangulation, which is one technique for grouping the points into triangles, usually triangles with certain properties (constrained Delauney triangulation).

Theodoros
05-21-2002, 06:53 AM
Hi there,

I suggest visiting www.vterrain.org (http://www.vterrain.org) . They have done a magnificent job regarding terrain rendering and developing GIS applications. There you will find answers for all your questions.

Robbo
05-21-2002, 07:02 AM
Graphics Gems I also provides an article on how to generate the required connectivity information (ie. how to go about joining two peaks of contour information).

That is assuming your `contour' information is just that - points from the contours and not just a regular heightfield representation.



[This message has been edited by Robbo (edited 05-21-2002).]

thanhnt
05-22-2002, 02:09 AM
I have been trying to find Delauney Triangulation but I do not know exactly which I should read because there is a lot of papers about this algorithm.
I would like you to give me a advice?
Thanhks

JeeTriX
05-22-2002, 02:43 AM
i spent a little time on triangulation myself, did not tconsider it easy actually. I found a nice site wich presents and shows 4 different approaches:
http://www.cse.unsw.edu.au/~lambert/java/3d/delaunay.html


You can't find there any course or tutorial tough, but with some google'ing i managed to implement a divide&conquer algorithm.

JX