2007 Surface converted to Civil 3D

[rschaff]

I received an older cad file (Pre. 2010) from an outside contractor which was stripped out. I need to verify the volume calculations they provided using the original surfaces they used. This is not a cooperative venture. With this in mind I need to be specific in what I ask for, taking into consideration they will not create anything new, I can only ask for what they currently have. So my question is what specifically do I need to ask for?

[indydrafter]

If they have existing and proposed contours at elevation, that would be a great source of information to utilize in recreating your surfaces. If they have points, that would be even better, but you should be able to get by adequately building existing and proposed surfaces from their contouring.

[jmeyer.186809]

If they have existing and proposed contours at elevation, that would be a great source of information to utilize in recreating your surfaces. If they have points, that would be even better, but you should be able to get by adequately building existing and proposed surfaces from their contouring.

I would say get the 3d lines and recreate the surface from that. That way it will be exact. Creating a DTM from contours should always be your last resort. Contours don't recreate a accurate DTM. All that does is creates uniformed slopes and flat spots between contours and we know that isn't the case. Ask them for the Surface folder in the DTM directory and create a new DTM from a TIN file or just ask for the 3D lines the represent the TIN. Then in C3D just create a new DTM and define the 3D Lines as breaklines and it will recreate the DTM exactly as they intended. If you don't use a boundary it will create some long triangles but those are easily fixed.

[indydrafter]

You are totally correct about 3D lines of the TIN being the most accurate way to recreate a surface that was developed by someone else. I was just working off the understanding that this information wouldn't even be available based off the description of the files being "stripped out." If those TIN lines are available, by all means use them.