Building Pad

Creating a Building Pad is very challenging but can be accomplished through using Feature Lines
This is taken from Autodesk Civil Survey Solutions Blog Video found here at this link.
Note: You will want to have an existing surface of the grade created.

First Create a surface of the finish floor.

Next create a feature line from your CAD Layout lines representing your Building Boundary.
 This is done with the feature lines from object tool.




Make sure to give the feature line a name.  (FFL is sufficient).  These settings will work as we want to assign an elevation.  You may not want to delete the existing entities.  (See Left Image)














Next set the elevation you want this elevation at (this is the proposed elevation.  It will make all points of the building the same)  If your building has different elevations, you may want to make different pads.










 If you right click on the feature line and select Elevation Editor, you can edit each point's elevations in the panorama.  This is similar to the alignment.




 Next select the building pad feature line, right click and add to surface as break line.




 Add a description to the Break line.

Now create a surface for the bottom of the building pad.  (for volume comparisons)


Edit the surface definition to past from the existing building definition.


Change the elevation to be lower.  Select edit in tool space then lower surface to indicate subgrade.

 

After complete, select the new surface and select volumes to compare surface against surface.  You may add cut / fill factors to accommodate shrink / swelling of dirt.