Procedural Colosseum

Procedural rules are normally associated with creating detailed 3D models for a large set of data.

CGA (Computer Generated Architecture) rules are also effective in terms of reducing the time it takes to create a detailed landmark (such as the Colosseum) manually. This post shows a simple process and the code that was used to create a quick landmark.


A simple arch and ledge object (.dae) was created in Sketch Up, which was used on the outer level.

Arch collada object from SketchUp

The Colosseum footprint digitized manually as a shapefile from the ArcGIS Imagery basemap.

Oval footprint shapefile

The code with some comments is below:
## Levels attribute serves as a counter, similar as the ## count in a for Method attr levels = 4 Lot--> Go ## The outer level only has an offset of -2, therefore it ## calls the Level Rule with an argument of (-2) Go--> case levels == 4: Level(-2) case levels == 3: Level(-15) case levels == 2: Level(-15) case levels == 1: Level(-15) else: color("#FFC68C") ## The Level rule creates an offset using the argument is ## was called with (x). It then calls the Border_Split rule ## to extrude each level Level(x)--> offset (x) Border_Split Border_Split--> comp(f){border: Extrude| inside: Recursive} ## The Extrude rule extrudes each level 12 (level height) * levels, making ## sure that each ## level's height is reduced by 12. ## Also the first level (a.k.a the outside level) is represented ## differently from the ## other levels, as it will have Arches on the side Extrude--> case levels == 4: extrude (levels*12) Split_First else: extrude (levels*12) Split_Rest ## The recursive rule deducts 1 from the counter and Re-calls the Go rule, ## creating a different extrusion height for each level Recursive--> set(levels, levels - 1) Go ## First (outer) level is divided into the front (which are assigned arch ## geometries) and top sides (tower) Split_First--> comp(f){front: Wall| top: Tower} ## Splits the outer-wall vertically every 12 meters, leaving a 2 meter ## ledge ## at the top. Each split is assigned an arch, while the ledge keeps its ## normal shape Wall--> split(y){{12:Arch}* | 2: Shape} Arch--> i("data/Raw/Arch.dae") r(0, 90, 0) s(scope.sx-0.1, scope.sy-0.1, 5.5) color("#F1B57E") ## The top part of the outer level is split into blocks on the X and Y axes ## and the middle bloch is extruded 5m creating a pole/tower Tower--> split(x){2.6:Shape| 0.2: Tower2| 2.6:Shape} Tower2--> split(y){1: Shape| 0.2:TowerExtrude| 1: Shape} TowerExtrude--> extrude (5) Color ##The remaining levels are colored dark grey on top and light on the sides Split_Rest--> comp(f) {back: DarkColor| top: Color} Color--> color("#514E4D") DarkColor--> color("#F1B57E")



The Result: