What is a Site Model? - A site model is a way of looking at 3D…
Vectorworks Tip #208 – Site Modeling – 2D Polys to 3D Contours
If you have a set of 2D polygons that represent contours, you can use the command 2D Polys to 3D Contours from the Landmark or AEC menu. This command will take your set of 2D polygons and convert them into 3D polygons at the appropriate heights. Then you can use these polygons to create your site model. Use this command with polygons that have regular elevation spacings.