As far as I can see GRASS doesn’t provide any ready-to-go tool to generate TINs from grid digital elevation models. I know I can transform a grid to a regular mesh somehow (probably using the Triangle lib for the last step) but I can’t find tools to generate TINs, given a certain amount of tolerance, which preserve significative locations (like those obtained by TPI for example) and shapes (in a morphonetric sense).
Does anybody has experience on this? The general aim is generating terrain meshes (to be further decimated for LODs) to be employed in a 3D context.
I can’t find tools to generate TINs, given a certain amount of tolerance, which preserve significative locations (like those obtained by TPI for example) and shapes (in a morphonetric sense)
Hi Mark,
thanks for the reply but it’s not what I’m looking for. v.triangle is a front-end to Triangle, to generate a Delaunay triangulation on points and, eventually, breaklines.
I’m lookink for something that generates a TIN from an elevation grid (raster).
giovanni
···
I can’t find tools to generate TINs, given a certain amount of tolerance, which preserve significative locations (like those obtained by TPI for example) and shapes (in a morphonetric sense)
Hi Mark,
thanks for the reply but it's not what I'm looking for. v.triangle is a
front-end to Triangle, to generate a Delaunay triangulation on points and,
eventually, breaklines.
I'm lookink for something that generates a TIN from an elevation grid
(raster).
giovanni
Il 05/dic/2014 14:14 "Mark Seibel" <
mseibel@
> ha scritto:
Hi.
I can't find tools to generate TINs, given a certain amount of
tolerance, which preserve significative locations (like those obtained
by
TPI for example) and shapes (in a morphonetric sense)
On Fri, Dec 5, 2014 at 6:01 AM, G. Allegri <giohappy@gmail.com> wrote:
As far as I can see GRASS doesn't provide any ready-to-go tool to generate
TINs from grid digital elevation models. I know I can transform a grid to a
regular mesh somehow (probably using the Triangle lib for the last step)
but I can't find tools to generate TINs, given a certain amount of
tolerance, which preserve significative locations (like those obtained by
TPI for example) and shapes (in a morphonetric sense).
Does anybody has experience on this? The general aim is generating terrain
meshes (to be further decimated for LODs) to be employed in a 3D context.
I'm not sure if this would fulfill your requirements but I would use
v.delaunay [1]. To get the points, you can use v.random [2, 3] or some more
clever method.
Thanks for the suggestions. I already had a look at that page, but nothing seems to fulfill my requirements.
Using v.random is not a solution. I should select significative points, and significative lines, to feed Triangle. Random selection will probably miss important locations (e.g. peaks, etc.).
As far as I can see GRASS doesn’t provide any ready-to-go tool to generate TINs from grid digital elevation models. I know I can transform a grid to a regular mesh somehow (probably using the Triangle lib for the last step) but I can’t find tools to generate TINs, given a certain amount of tolerance, which preserve significative locations (like those obtained by TPI for example) and shapes (in a morphonetric sense).
Does anybody has experience on this? The general aim is generating terrain meshes (to be further decimated for LODs) to be employed in a 3D context.
I’m not sure if this would fulfill your requirements but I would use v.delaunay [1]. To get the points, you can use v.random [2, 3] or some more clever method.
Thanks for the suggestions. I already had a look at that page, but nothing seems to fulfill my requirements.
Using v.random is not a solution. I should select significative points, and significative lines, to feed Triangle. Random selection will probably miss important locations (e.g. peaks, etc.).
As far as I can see GRASS doesn’t provide any ready-to-go tool to generate TINs from grid digital elevation models. I know I can transform a grid to a regular mesh somehow (probably using the Triangle lib for the last step) but I can’t find tools to generate TINs, given a certain amount of tolerance, which preserve significative locations (like those obtained by TPI for example) and shapes (in a morphonetric sense).
Does anybody has experience on this? The general aim is generating terrain meshes (to be further decimated for LODs) to be employed in a 3D context.
I’m not sure if this would fulfill your requirements but I would use v.delaunay [1]. To get the points, you can use v.random [2, 3] or some more clever method.
I then open dem.vtk in Paraview, and run the Delaney 2D filter (default options) save as .PLY file.
Next I open the resulting .PLY file in Meshlab and run Quadric based edge collapse strategy - specify desired triangles, preserve normals and I save as .OBJ file. For my needs I choose "Preserve boundary of mesh”.
