Alice Community  

Go Back   Alice Community > Alice 2 > How do I...?

Reply
 
Thread Tools Display Modes
.DEM files in Alice
Old
Hello Mello
Guest
 
Status:
Posts: n/a
Default .DEM files in Alice - 06-05-2008, 05:54 PM

Hi. I need to do a project involving landforms and I've found a suitable .dem file from the GTOPO30 website. I've tried to look for converters to convert it into .ase but I couldn't find any. Any suggestions or functions in Alice that I've overlooked?
   
Reply With Quote
Old
DrJim
Guest
 
Status:
Posts: n/a
Default 06-06-2008, 09:07 AM

First, with this type of question, you really need to give more information. .dem at GTOPO30 really sounds like something from Star Wars.

Using a good reference on extensions (http://www.wotsit.org/list.asp?al=D ), I assume you are talking about something from the Geological Service. I doubt that you will be able to find anything that will convert to .ase directly - .ase doesn't seem to have been a very popular format.

If it is really a mapping format, I'd try to get to .3ds format first - then use Biturn (URL elsewhere in the form) to convert to .ase. Another choice would be AutoCAD format (.dxf) - which might be better for maps - but you then would have to use something other than Biturn (Blender would be one choice) for the file conversion. (I usually us the rather ugly path of going from .dxf to .3ds in Blender and then using Biturn to get to .ase.)

Good luck, and if you do have some succes, please post the results. Realistic terrain maps would be a very nice thing to know how to do.

Last edited by DrJim; 06-07-2008 at 06:34 AM. Reason: Corrected several errors on extension type
   
Reply With Quote
Old
Hello Mello
Guest
 
Status:
Posts: n/a
Default 06-06-2008, 04:52 PM

Sorry about that. I guess I've forgot to mention that DEM stands for Digital Elevation Model and that GTOPO30 is a project in which the world is mapped in that format. I've managed to turn the file into a .asc file through a demo Okino Nugraf and Biturn but when I try to import it into Alice, it says that there is no converter for the file type.
   
Reply With Quote
Old
DrJim
Guest
 
Status:
Posts: n/a
Default 06-07-2008, 06:32 AM

Sorry -made a typo, something I too often do.

You need to import in .ase format.
   
Reply With Quote
Old
Hello Mello
Guest
 
Status:
Posts: n/a
Default 06-07-2008, 02:52 PM

It doesn't seem that biturn can export to .ase files (I'm using version 0.824) so instead, I used the demo version of 3ds max. Now, when I tried to import it into Alice, it said "Unable to find file "DEFAULT.TIF" specified on line 2802".
   
Reply With Quote
Old
DrJim
Guest
 
Status:
Posts: n/a
Default 06-08-2008, 07:50 AM

Ah, welcome to the fun of object import into Alice.

I'm using version 0.88 of Biturn but I know some people have had trouble with the site and downloads - it doesn't seem to be actively maintained. If you can't get a good working version, another free alternative is 4D Blue (http://www.4dblue.com/ ) though I don't think that site is actively maintained either. Afraid you'll just have to keep trying until you find one that works.

As far as the .tif message - that's just a warning like many Alice "error" message. It's particularly useless in this case since Alice won't import textures with objects anyway. Ignore it (click Cancel) and continue.

Two other problems sometimes come up. Some objects import with "is showing" false or opacity of 0% and you have to change those parameters manually. Also, you will sometime get naming convention errors - the only way I know to fix those is to manually edit the .ase file in WordPad or something similar.

Finally, one basic check is to see if an object shows up in the Object tree after the attempt at importing. This will tell you if you just need to work with the object parameters or if the import failed completely.
   
Reply With Quote
Old
Hello Mello
Guest
 
Status:
Posts: n/a
Default 06-08-2008, 07:04 PM

I finally got it to work...barely.

My Method:
1. Download a .DEM file from this website: http://edc.usgs.gov/products/elevati...0/gtopo30.html
(has the whole world)
2. Use Okino NuGraf to convert it into .3ds
(here's a demo: http://www.okino.com/conv/demos.htm))
3. Import it into 3ds Max or similar program
4. Download Polygon Cruncher for 3ds Max or other polygon reducing program
(http://www.mootools.com/plugins/down...t=1&register=1
5. Reduce the model about 85% (or more [detail vs. functionality])
6. Use 3ds Max or Biturn to turn the model into .ase (ASCII Screen Export)
7. Import it into Alice

Problems:
1. Some times the download from the website freezes (either that server or my faulty router)
2. Unless you get the full version, every 5th polygon will be missing in the exports (I'm currently using a friend's NuGraf)
3. I know that 3ds Max (full, also from friend) works but not if any other programs/demos work.
4. You should reduce the different parts of the DEM model in parts (when I tried doing them together, 3ds Max used up all of my 2 Gigabites of memory and had to close.
5./6. No problems.
7. Alice will first display the warning message described earlier and then freeze for a period of time (depending on by how much you reduced the model).

My final problem: I used a large DEM and now, the model is curved. How do I efficently move the camera around the curved surface?

Thanks Dr.Jim for your advice!

Last edited by Hello Mello; 06-09-2008 at 07:04 PM. Reason: Forgot acknowledgement
   
Reply With Quote
Old
DrJim
Guest
 
Status:
Posts: n/a
Default 06-09-2008, 06:57 AM

Congratulations - that was a lot of work on a difficult data base. Thanks for posting the details.

As far as following a curved surface goes (or any real terrain following) - I've never seen that done very well in Alice. The only time I've personally been involved in a project doing that (using downloaded geo data, Open GL and C++) - we actually went and referenced to the mesh vertex coordinates.

That apporach worked great and the terrain following was easy - but there was a lot of data base managment work to keep the terrain meshes a reasonable size and the edges of the segments aligned - the same thing you noted. Since you can't edit object meshes in Alice, however, that doesn't help much here - sorry.

One obvious approach would be to put in several reference objects (maybe low polygon hemispheres) aligned to the terrain and reference movements to them.

A completely different approach would be to use one of the game style terrain generators. I know Anim8or has one and a program called Terragen (http://www.planetside.co.uk/ ) is designed especially for that purpose.
   
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Copyright ©2022, Carnegie Mellon University
Alice 2.x © 1999-2012, Alice 3.x © 2008-2012, Carnegie Mellon University. All rights reserved.