I'd like to create 3D model of some real terrain (to be exact it's about some real roads and only as much as 80m to 100m of roadside - 40m to 50m of each side). As I don't have access to highly detailed local maps, my only source of topographic information of given terrain will be Internet.
Now my question - what would be the best approach to create such 3D model and make it as detailed as possible? I know I won't be able to get very detailed elevation data (AFAIK, DEM for Europe has only 90m resolution) but on the other hand it's still better than nothing. But also I don't know what would be the best source of detailed topographic data? Should I use Google Maps and work on its KML files or OpenStreetMap gives better results? Or maybe there are some other resources for getting the information I will need? BTW, would be some in-car GPS system of any help in this case?
I'd like to add that I want to model only the surface - the vegetation, buildings and other objects are not needed. Also I won't need any geographic co-ordinates of terrain as I need to have only right measurements in meters.
I'm totally new to this subject so any kind of help will be very much appreciated.
Thank you in advance for reply.
EDIT: Thank you everyone for your comments. I'll try to add more information on this project.
Source of data - AFAIK, the most detailed DEMs for Europe (Western and South Europe and also North Africa are my areas of interest) can be obtained from ASTER and Landsat. Both have 30m resolution so it's as accurate as I need it to be.
3D model of terrain - I'd like to reconstruct some real roads that used to be parts of famous rallies or races in the 50's and 60's (Coupe des Alpes, Liege-Rome-Liege, Rallye del Sestriere or Tulpenrallye). Of course not whole roads as it would take ages for me, only some sections that can be about 7km long (that's game engine limitation). So I need a 3D model of surface of some specific road so I could edit it in 3DS Max 5 program. Or some other 3D modeling program (FreeCAD or Pov-Ray) as I need 3DS Max 5 only for texturing, adding some objects like buildings, trees, people, sponsor banners and finally exporting max file to bmf file (it's a format that Rally Trophy uses). And the game looks like in the link below:
Now, my biggest concern is the right method of generating such 3D model of terrain - what kind of programs do I need? And also how to mark a road on it?
I'm sorry I cannot explain it any better. But please ask as many questions as you need to.