Revit meets Procedural: Best of both Worlds

Often the buildings of new/re-developments are designed by architects which designs the buildings in a specialized software type. An example of this is the use of Autodesk's Revit software. Creating one detailed building can be a time-consuming process. Imagine modeling an entire neighborhood! This post looks at how CityEngine can streamline this process for an entire new development.

In the example developers created 4 individual housing building types (55 sqm ; 65 sqm; 85 sqm and 110 sqm) in Revit.

Revit models

The objective was to randomly place one of these 4 models at each residential lot of a new development area. In order to place these models on a lot using CityEngine's procedural rules, the models had to be exported to a .obj file format, which can be easily utilized by CityEngine.

The Revit models were however only created for the residential lots, while the generic buildings for the commercial lots had to be created procedurally. Therefor the first action that the rule does is test to see whether the Zone attribute of the feature is either Residential; Commercial or something else. As seen in the Lot Start Rule below:

Lot--> case Zone == "Residential": 
SplitErf
case Zone == "Commercial":
CommBuild
else: NIL

For residential buildings, a setback area of 6.5m were created and colored dark green, while the remainder was used to place the .obj models. The models were then Scaled, Centered, Colored and Placed...

SplitErf-->     setback(6.5){ all: t(0,-0.2, 0) DarkGreen| remainder: Building }
Building-->    s(10,5,10) i(BuildingModel)t(0,-1, 0)  center(xz) LightGrey

Residential areas

The commercial buildings had no Revit models and had to be generated procedurally. The first step (similar to the residential buildings) was to create a "Building footprint" from the existing feature using the setback tool. The outside area of the feature was colored Beige while the remainder was extruded to the randomly selected building height. The extruded buildings were then divided into a top part (Roof); a front side (entrance) and the remaining sides. The building block was then split vertically and horizontally to create building tiles. These building tiles each represented a window, which were made transparent.

Commercial Building

For the front side of the building an entrance roof overhang was created (the ground floor of the entrance was also colored differently than the other sides.

Because the Commercial buildings weren't the focus point of the scene, a generic "Commercial-appearance" rule could be applied to all the features. It only needed to indicate where commercial areas were located (not a lot of detail necessary).

Additional features were added such as Static Buildings ( for example Religious buildings, a Hospital, Clinics; a School; and Sport Stadium) as well as the surrounding area elevation and imagery which contributes to a better understanding of the area.

Hospital

Stadium and Clinic

The CGA rule file that was created, generated Residential and Commercial buildings in completely different ways. 3D building geometries were generated  using existing Revit models for multiple features at the same time or (in the case where there were no existing models) used the procedural CGA functionality to create new buildings. The end result is a 3D scene that moves uninterrupted between different software types.

School (SketchUp)