Micheal,
Yes, it is the shading that makes everything pop out. But you don't necessarily need the topo information to make it happen. A topo survey of an as-built is great, but it is rare a course owner will get that done, simply because it is expensive. I would love to do a yardage guide based on a detailed as-built contour plan.... It would be spectacular, but I doubt a lot of people would be able to understand it properly....
John,
You don't necessarily need CAD software, although it helps a lot. Shading can be added artistically by hand, based on a good review of the site. A good visual memory will go a long way to acheive this.
Ryan,
Textures can be created fairly easily, using photoshop. A technique I have tried is to take a good aerial on google earth or any other source, zoom in really close on a good texture you like (like trees, water, shrubs, gorse, etc...) and save the picture. Then, using the clone tool in photoshop, you can replicate that texture over a huge surface. Then add a touch of color, blend the two layers and "voilà", as we say in french, you got a texture! (I just hope this technique is actually legal!)
It takes a lot of work to create yourself a good library of textures, but it is worth it. You can also buy some over the internet. Just do a search for textures, and you will find tons....
As for 3D images of trees and other objects, that, I beleive, takes a lot more work....
YP