Are you importing CAD drawings or starting from scratch?
I am importing topo data from CAD. I also need to "drape" other CAD lines onto the terrain. I know how to do it in SU, but I have recently started using 3ds max and didn't know if there was a big advantage to creating the terrain in that program or just building everything in SU and importing. thanks!
Do you have access to Civil 3D? You have the most control that way & then could export either a TIN or breaklines (feature lines in Civil 3D) into your rendering program of choice. Might be overkill if you don't need survey-level accuracy, though.
I do have civil3d actually and higher the accuracy the better. (I am modeling a before and after grading plan for a large scale land development) Thanks for the help, I will give it a try.
The Civil 3D feature lines work a lot like SketchUp lines, interacting with each other as you raise/lower them. Just keep items you don't want interacting in different "sites", much like SketchUp groups and you'll be fine. Civil 3D has many useful tools for editing the feature lines, such as by slope, by reference surface ("draping" on existing surface, for example), etc. Build your finished surface with feature lines, individual points, manually drawn contours, or whatever combination is needed.
Adding interactive surface labels for spot elevations and/or slopes, that automatically adjust as the terrain is edited, are mighty handy and a good check for problem areas. The help files should have all the information you need, if you have the time to go through them. Good luck!
if your using 3ds, import your autocad lines into 3ds. then, hopefully, your topo lines are saved in different layers, but your click on each one and hit w, this allows you to move your line in any direction. on the bottom of the screen youll see 3 little boxes labeled x,y, and z, respectively. here you will set your height of topo line to your desired height. after do you this your topo should resemble your topography, but is just the skeleton of the model. highlight all of the lines and under the create panel, click in the dropdown bar the compound primatives or something like that, then select terrain, and there ya go. its easier done than said honestly