Unexpected contour lines on surface after adding 3dfaces

[Bryanherron]

This is my first attempt at doing a grading plan so I am just muddling my way through it and have certainly not figuring out best practices yet, so be patient with my process. What I have is an urban renewal project with a detention pond/park are for future housing & business development. So the centerpiece is this pond which grading that was not an issue, but the 12-18 foot tall retaining walls, ramps stairs, etc. were a whole set of hurdles and the first thing I figured out that actually seemed to work was manually creating 3dfaces for every wall face, ramp ect., with the 3dface edges acting like breaklines. It all added easily to the surface, but I got some unexpected and clearly wrong results with the contours. On my verticle walls I used a 0.125 offset so that the walls all had a tilt from top to bottom. So I see two issues with the contours that I am wondering if there is a single fix for.

Here is a corner of the wall where the thick magenta line is the bottom of the wall and the pond is to the NW. The blue is the top of the wall and to the S & E is a sidewalk. All of these contours should be between the Magenta & Blue lines.
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Here’s a shot of one area where the 3dfaces are at the correct elevations, but the contours are way off and I wonder if this is the same problem with the corners of the wall.
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How do I get the contour lins to stay on the wall????

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[rkmcswain]

Kind of hard to tell without having the DWG file.

Contours are a _result_ of the triangulation. They simply connect LIKE elevations on the TIN. Have you examined the TIN lines (triangles) to see what they are doing?

[Bryanherron]

I fixed the second issue after discovering the odd behavior of the tin. Being my first shot I wanted to keep the 3dfaces organized and color-coded so I put them on their own layers, wall face, sidewalk, grass, etc. It also helped me visualize them while I was building them. When I created the 3dfaces, I made 4-sided faces when possible, when I exploded the surface to edit the triangles they were all there AND there was a complete new set of triangles on the 0 layer mingled in. Did I error in this process or was that to be expected? Regardles, as I said, I was able to fix the triangles on the sidewalk ramp and stairs that each had a corner that had decided to attatch to the top of the wall instead of the the bottom of the wall even though the 3dface was properly attached to the bottom and offset (0.125 in plan view) from the top of the wall. For my deadline I exploded the surface and edited the contours by hand, but I'm sure this 2-week hair pulling exercise could have been accomplished with correct outcome in a day if I knew the best practices. In the CAD file just pick any corner of the wall and take a close look at the contours and explain to me why the surface that was created did not attach to the 3dfaces, but seemed to only use the edges of the faces as breaklines. Can this be fixed, Or do I need to start over from a completely different direction?

[cadtag]

>>why the surface that was created did not attach to the 3dfaces, but seemed to only use the edges of the faces as breaklines.

because that's the way c3d is designed to work. Breaklines, faces, points, other entities create triangles, triangles create contours.

[Bryanherron]

So, does everyone just do contours by hand in this situation?

[Opie]

Are you creating your wall exactly vertical? If so, you will need to put a slight offset with the upper elevations, so the lower elevations can be seen.