Caves and DEMs

[rcallicotte]

Has anyone looked into making DEM caves or transforming these DEMs into Terragen files to create caverns/caves?  I found this in one Google swoop and am ready to go spelunking!   

http://www.resurgentsoftware.com/winkarst.html

[dhavalmistry]

I dont see any link to download dems.....if you found the...can you please upload somewhere

I would like to play with this too...

thanx

[rcallicotte]

I'm still looking.  So far, all I can find are files related to NED or DBF. 

[Oshyan]

Traditionally speaking "DEM" means "Digital Elevation Map", so the term isn't strictly applicable to a true volumetric cave description since there is both a floor and a ceiling (which means two altitude values for each vertical sample). DEM's are usually heightfields which can essentially be visualized in greyscale with white values being higher and black being lower. A cave can't truly be described this way unless you use multiple heightfields.

The only way to currently bring in some kind of cave model would be with imported geometry (an object file), but it would probably be difficult to get it to blend properly with the terrain. In the future there may be a way to exclude terrain rendering from space that an object occupies, which would make imported cave models work better.

- Oshyan

[rcallicotte]

Thanks.  I've been learning this the hard way.  LOL.  But, there seems to be programs that model caves and I was hoping for a standard file I could transform.  This makes sense about needing an object file.  But, I wonder what would happen if I created something in Bryce or (more unlikely for my level of skill) in World Machine, which is or resembles a cave.  In this case I could import that into TG2, right?  And if I loaded this heightfield with a negative placement, then I could have it go under the surface and be a cave.  Or not?

[Oshyan]

World Machine could not create any true "cave" because it operates on heightfields and they only allow specification of a single height value for any given vertical sample. That's just a limitation that can't be overcome within that system at this time. You could create a heightfield that could be made to make a depression in a TG2 scene, but it would be downward into the earth, not lateral, unless you used it as lateral displacement on the side of an existing terrain, and then still it would not come close to simulating a true cave because it would only be a depression with again a single sample of "depth" in any given location. So if you can visualize this, looking into a cave, if you see a part of the cave roof coming down from above, but then you walk beyond it and can see up into a larger cavern, this would be impossible to model with the technique you're talking about. Again it would have to be modeled in 3D geometry to work.

- Oshyan

[monks]

Calico, the closest you will get to usable 3D models of cave systems is from VRML; as in Larry Fish's 'Compass':
http://fountainware.com/compass/

The software converts the vectors from the cave survey into 3D navigable tunnels. The last time I looked at this was a couple of years ago- things have no doubt moved on a little since then but probably not that much. Shp file format are also used.
If you could find a way to convert from the vrml objects to a tgd readable form, you might at least have a glimmer of a glimmer hope, but  as Oshyan says, 3D polygonal objects and heightfields are very different beasts.

monks

[rcallicotte]

Thanks.  I looked at this yesterday without knowing for sure.  Someone mentioned taking the cave data and turning it into an object, but then someone who tried it had trouble rendering anything within the object tunnel.  I'm still experimenting and will come back with more info.

Calico, the closest you will get to usable 3D models of cave systems is from VRML; as in Larry Fish's 'Compass':
http://fountainware.com/compass/

The software converts the vectors from the cave survey into 3D navigable tunnels. The last time I looked at this was a couple of years ago- things have no doubt moved on a little since then but probably not that much. Shp file format are also used.
If you could find a way to convert from the vrml objects to a tgd readable form, you might at least have a glimmer of a glimmer hope, but  as Oshyan says, 3D polygonal objects and heightfields are very different beasts.

monks

[rcallicotte]

I haven't given up on the cave ideas, but I'm changing my focus to utilizing TG2TP's power by itself without creating any extra objects.  My beginning TGD is here - http://forums.planetside.co.uk/index.php?topic=1316.new#new

[neon22]

Calico, the closest you will get to usable 3D models of cave systems is from VRML; as in Larry Fish's 'Compass':
http://fountainware.com/compass/

The software converts the vectors from the cave survey into 3D navigable tunnels. The last time I looked at this was a couple of years ago- things have no doubt moved on a little since then but probably not that much. Shp file format are also used.
If you could find a way to convert from the vrml objects to a tgd readable form, you might at least have a glimmer of a glimmer hope, but  as Oshyan says, 3D polygonal objects and heightfields are very different beasts.

monks

Here is the fulford wrl converted to obj from the Compass site.
Doesn't look like its much use to us unfortunately :-(

[monks]

 I always follow these cave threads with interest - it's how I first got interested in terrain. I think we need a new heightfield standard somewhere down the road- imo it has to start really with the terrain modellers- not much use in a renders runtime procedurals in those.
Still, we've already seen the impossible in TG2P- ! 

monks

[chefc]

I think that we can already make some decent caves renders with TG2.
Here are two of my latest images :
http://olivier.cousinou.free.fr/TGD/Images/Red-rock.jpg
http://olivier.cousinou.free.fr/TGD/Images/Inside-cave.jpg
Terrain used is a classical DEM file, wired to some redirect trickery.
Please don't ask me to share the files... test by yourself
Olivier

These are GREAT example's  of what a little patience will give ya Thank's for the inspiration Oliver .

[rcallicotte]

...patience and know how.  Please post if you're able to come close to Olivier.  I will try...