Pasting surfaces in Civil 3D

Is it possible to change the grading style that is automatically implemented when pasting one surface into another. What I am attempting to do is create a basement footprint into an existing surface in such a way that the drop from existing surface to basement surface is abrupt. What I am getting instead is a gradual, very shallow grade from the basement surface up to the existing surface. Any advice?

Thanks

Can you post a screen shot or upload your dwg so we can see it.

If I understand you right I have a feeling you will need to use the grading tools and use your eg surface as a target. If you are just pasting in the feature lines of your foundation/basement then the program will interpolate between those and the nearest surface points.

It may not hurt to give us a timeline (as detailed as possible) of exactly how you got to the point you are now at. Please include what you began with and what your final goal is.

Ok, from the top my progress reads like this:

1) I began with a CAD from which I intended to create a surface. Included in this file were all of the appropriately 'smart' topo lines, TC points and boundary info with which a simple surface would be easy to create. However, within this plan is a building footprint that includes several sub grade levels, each adjacent to one another and at varying depths.

2) So I first created independent surfaces at the appropriate elevations for each of the basement levels.

3) I then created what we might refer to as the target surface, which itself incorporated the topo lines, TC points and boundaries.

4) From there I then pasted each of my basement levels into the target surface in attempt to achieve what I can only describe as an immediate elevation drop from the target surface to where the basement footprints rested at the various elevations.

Unfortunately, when pasting each of the basements surfaces, the interaction between sunken basement surface and target surface resulted in a very gradual, tapered grading from basement footprint up to target surface.

What I would ideally like to achieve is an nearly immediate jump from, as an example, the -10' elevation of a basement level, to the 15' elevation of the immediately adjacent target surface.

I suspect that there is a grading function somewhere that pertains to level pasting, I simply cannot locate it.

If this makes any sense to anyone and should there be a communicable solution I would greatly appreciate it. I hope this helps. Thanks

It seems a bit peculiar that you would want to incorporate the building into the ground surface but... What I am thinking is to start over with your ground surface built from the contours, points, etc. Draw a line around the extents/perimeter of the foundation and add that line as a HIDE boundary to the ground surface so that the ground terminates at the line of intersection with the foundation. Then I would add the foundation as a 3d solid(s) and place it at proper elevation.

What is the purpose of creating this model? Presentation? Material quantification?

Thank you for your post silo, and to answer your question, I am creating this surface for a quantity, cut-fill, takeoff. Does hiding TIN lines affect volume takeoffs?

Ahh. Well let me change my answer then.

In this case you will need separate surfaces for your existing ground surface and your proposed building floor elevations, thus you will need, at minimum, 2 surfaces; an EG (existing ground) and an FG (finished ground) surface.

Next question:

Do you need cut/fill for the entire thing or separate for each floor elevation below grade?

I need cut fill for the entire finished surface and ideally would like these surfaces to act as one.

I'm thinking create your fg surface from breaklines/feature lines depicting the base of your foundation only. Then just simply do a cut/fill comparison between that and the eg surface. If you need help with that just say so.

Why would you like them to "act as one"? I suppose what you might do is draw a 3d polyline at the base elevation of your foundation (as previously stated) then offset that outward a small bit, maybe 1/100th or so (ie - .01) or even 1/1000th (ie - .001) and initiate the feature line from objects and select the line you just offset out. Check the box for "elevations from surface" and be sure the eg surface is the one selected (say yes for intermediate grade points). Now you'll have your base foundation elevation line and your eg ground line approximately where the ground would meet the foundation.

After that you can add the newly created feature lines to the fg surface. Then do the cut/fill comparison.

To complete it you might copy the eg surface and rename it to something like "composite surface". Then you will paste the fg surface into this surface for the final composite surface. Turn your eg and fg surfaces to a "no display" style. Turn the final surface to your proposed surface style or whatever you need it to be.

Does that make sense? I'm a wee bit tired right now. If you need more explanation tomorrow I'll give it another shot.