[GRASSLIST:420] Re: v.in.dxf

[Mauro Lacy]

Hamish wrote:
>> Sorry for the cross-post, but I'm trying to do almost exactly the 
>> opposite. That is, export a (raster) DEM to dxf. I was browsing the 
>> diverse grass modules, and the problem is I couldn't find a way to 
>> convert a raster DEM to a vector "surface" or "3d" file. So I can
>> later export it using v.out.dxf. I tried r.to.vect with horrible(and
>> maybe simply "not applicable") results.
>> I found some (non- free) programs that seem to do this (r2v, from 
>> ablesoft, by example) but it intrigues me if it can actually be done 
>> with grass(or with free software).
>>     
>
> Sounds like you want a TIN. see:
>
> http://baron.flightgear.org/pipermail/terragear-devel/2004-November/001087.html
>   
This looks promising. But seems to be work in progress:
http://www.bowdoin.edu/~ltoma/research.html
(see r.refine)
And as far as I can tell, no source code is available.
> or v.3Dtin
> http://www.fle.czu.cz/~jachym/programs/grass.html
> http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassAddOns
>   
This works! (altough v.delaunay is _extremely_ memory consuming)
After some minor corrections to v.3Dtin perl code, I was able to 
generate a 3D-vector TIN (altough maybe it should be more appropiately 
called a TRN).
I'm now stuck with the DXF file. v.out.dxf generates a valid DXF file, 
but it looks like 2d, not 3d.
Probably is just me :) I'm displaying it in qcad (I don't have Autocad 
at hand now). And maybe I just don't know how to display it in 3D.

Regards,

Mauro

> Hamish
>
>