3D Terrain Issues

I am having major problems trying to create a 3d terrain from linework I brought in from a dwg file. This terrain is to include a road, sidewalks, driveways, property lines, and house and garage for 14 different lots. I have the houses and garages setup as components created in a different sketchup file that will be bringing in. That works just fine. I have each of the contour lines at the proper elevation when I go “Draw” “Sandbox” “From Contours” to attempt to make the 3d terrain it works for the most part, but it creates all of these weird faces, mainly where the lines are close together. I have this area at the back of the lots where there will be a very steep slope grade. This is the area that doesn’t get created properly. When I select a smaller portion for just say two of the lots and run it its better but still not perfect. I’m a bit new to creating the terrain so any feedback and/or suggestions would be greatly appreciated. I’m not sure if its better to all lines for the contours or if lines and arcs are ok? Just trying to decipher why its happening. If its possible I don’t mind sharing the sketchup file. Thanks in advance for any suggestions or help. Attached is a screen shot with the contours shown in place along with the terrain. It would only let me upload one file because I’m a new user. There has to be an easy way to do this. I’m pulling my hair out. Maybe part of the problem is the number of edges. I tried using the simplify contours extension but that seemed to mess things up. I didn’t know if the curves would mess things up or not.

[quote=“adams_design, post:1, topic:8190”]
…If its possible I don’t mind sharing the sketchup file. …[/quote]
Try again uploading the file itself, or better yet, just the contour lines that are needed to shape the terrain.
Is that possible in a new post in this thread?

Looking at your image, I would guess that vertical slopes or ones with a negative slope are the problem. The Sandbox tool cannot handle these, Posting the contours file would clarify things.