is there a way to offset a surface face or faces perpendicularly rather than a perpendicularly not vertically off of the surface face?
The only way I know how is a workaround using a takeoff workflow.
It’s not clear to me if TBC uses some different math with the perpendicular offset than Siteworks/Earthworks, but they do give a disclaimer…
In our Cloud Services functions we have a perpendicular offset surface function. It is not perfect because it sounds simple but it really isn’t. When you have triangles that are very steep, they push more sideways than up or down, and that causes them to cross over other triangles and cleaning them up is extremely difficult to do - but for design surface shapes and rolling terrain where slopes are typically less than 1:1 it works pretty well in most cases
Alan