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Planning envelopes are important in every state in my country and many others in greater Europe. A design is more likely to be built if it conforms to some of these council or authority requirements and fits inside diagrams such as the one above.
It is not a sexy topic, nor is it of interest to juniors, and trolls, but is of great interest to millions of professional architects over the world. My study of Revit through courses, text books, tutorials, and including these forums reveals there does not seem to be much about it so far.
Archicad has a dedicated set of tools to deal with such planning issues where one can drape a pink envelope over a design.
Terrain form survey data comes from a land surveyor and can be easily modelled in Revit, there is a lot on that and it is easy. One can draw a series of model lines on the boundaries and setback lines across the terrain, these can be raised to the required heights using profile modeler, but a problems occurs when it comes to copying the terrain to the upper level or in the illustration 8.5m height as each segment has a different angle of attack per say. The existing terrain is important base and the town planners want to see how its "roof" when raised is penetrated or not by the design, often sites, depending on the bylaws, have a cap and some can be difficult to build on if a site has considerable slope. It can be a bad idea to do excavation, pre-design before the planning envelope is established, but that is incidental to the purpose of this exercise.
An approach can be taking the terrain out of Revit into SketchUp or regular AutoCAD or Archicad to make up the lines and heights in a mesh with the 45 degree champers from the springing points and cut through the upper mesh. On then can drop it back into Revit with a transparency is one way of modelling it where one can use massing and site and get an accurate upper roof. The coordinates of entry have to be exact in height and location and grid lines help with this. Often council may disagree with how the envelope has been constructed and ask for revisions.
An example of an envelope from a different municipality.
Revit is ok for using the massing and site/terrain tool in 3d but there is a difficulty where both ground and planning envelope terrain can block out a section with a hatch in elevations in some templates, and this is a tough route using VG and blocks, to separate the terrains out without having to redraw model lines all over a section if it moves. The sections and elevations are where levels and lines may need to be dimensioned and annotated with levels to prove to the planners that the design is inside the envelope.
The lines of the "roof and champers", as the illustration are useful in these sections and elevations but not the internal hatch which Revit defaults to, have also tried using a separate file to model the terrain and that works to a point, but it feels pretty clumsy.
One day the Revit developers will put their put their minds to a set of tools for such purposes as do their competitor, if enough professional architects request it.
I remain curious if anybody has an efficient work flow around for these "planning envelopes" that they would like to share ways it could be done better in Revit?
Cheers
Try this link.
An intelligent well laid out answer to the question.
Thank you ARCetype.
- Ensure the existing toposurface is set to existing phase & name EXG
- Copy EXG, paste to same place & name NEW
- Copy NEW, paste to same place, name ENVELOPE & move up to required height at boundary
- Split surface of ENVELOPE at boundary. Delete external portion
- Copy ENVELOPE up to internal maximum height (ENVELOPE 2)
- Edit surface of ENVELOPE & delete all internal points
- Create Railing with a 45 Deg plane along the boundary & Pick New Host to ENVELOPE
- Set site plan to Consistent Colors
- Split surface of ENVELOPE 2 at intersection of railing plane. Either do this separately for each boundary side or all in one go. Delete external portion(s)
- Copy ENVELOPE 2 & paste to same place (ENVELOPE 3)
- Merge ENVELOPE with ENVELOPE 2 (Untick Remove points on common edges) to create PLANNING ENVELOPE
- Split surface of PLANNING ENVELOPE at boundary if required. Delete external portion
- Adjust colour & transparency of PLANNING ENVELOPE material. make ENVELOPE 3 material transparent
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