I am creating a Revit Project from a survey of a House and its garden [River Front Property]. I have successfully imported the Site Plan,1st and 2nd Floor Plans using shared coordinates orienting them all to both Project North and True North as well as Project Levels [Project Base Point] and Actual Site Levels [Survey Point] [see also System Family:Level. Type Circle Headroject Datum. Constraints: Project Base Point/Survey Point].
The Site Level used to coordinate the Site and Floor plans was 99970 millimetres [99.970 Metres. I converted from Metres when inputting it into Revit?] and the floor Plan levels have automatically matched the differences in height both 'Relatively' and 'Absolutely'. That is to say:-
The 1st Floor level [Ground Floor in UK]l of the House was set at 100.000 Metres in the Autocad survey - this now reads 100000 on the Revit Level in the Elevations - if the Revit Level properties Constraint set to Survey Point ] and 0 if the Constraint set to Project Base Point. The difference in Height between the 1st and 2nd Floor remains exactly the same whether displayed according to Project Base Point or Survey Point.
So far so good. However when I try to create a toposurface for the Site I immediately run into trouble - The surrounding Site falls away to the front of the House from 100Metres to 94Metres and rises at the back 100Metres to 102Metres. Unfortunately the resultant topo surface is being created way above the project model - the Spot Elevations seem to be being placed RELATIVE to the Model and not ABSOLUTELY to it. A Spot level of 99970 millimetres is being placed +/- 99970 millimetres above the 1st floor level of 100000 millimetres ie at at REVIT level of 199970.
Why is this happening when all the other levels ie: 1st and 2nd Floors conform to both Relative and Absolute Levels? Note the Imported Site Plan is in 2D but I am using it 's levels i.e: 94.275 Metres to place Spot Elevations i.e: 94275 [ABSOLUTE] in REVIT using MASSING AND SITE/ TOPOSURFACE/PLACE POINT.