cga Building Rules

Question

I'm new to CityEngine but I've made some progress learning the program by reviewing some of the tutorials.  I received a building footprint zip file from the Southeast Michigan Council of Governments (SEMCOG) that contains a shape file package.  The package .dbf file has building square footage, number of stories, building height etc (see attached).  Can you provide or identify the location of a .cga file that I can use or modify in my project to extrude the buildings to the correct configuration? I've used some of the .cga building rules in some of the examples without much luck.  Most of the footprints are ok but various buildings have the incorrect number of floors and heights.

Thanks,

mlnelson2@charter.net

BuildingsDocumentation111015.pdf

se2539 · Answer

You provided some pretty simple, yet extremely valuable information.  I was wondering why my buildings were extruding artificially high, all the while not realizing CE defaults to meters.  Obviously I needed to convert my data to feet, but I must have missed that in the tutorials I was following ... in any event, I am appreciative of your post.

DevinLavigne · Answer

Well, it wasn't behaving right for me either - so don't be hard on yourself. When an attribute is named to match a GIS field, the connection should happen automatically. For your data, it wasn't, which was odd - maybe it was the size of the data? Anyway, there is a way to map those attributes manually - see the help file for Connection Editor. Once they were mapped the code below worked perfectly.

const unitScale = case Unit=="Feet": 0.3048006096012192 else: 1

@Range("Feet", "Meters")
attr Unit = "Feet"

@Range (0.5,200)
attr STORIES = 0 #Should be a GIS Driven Attribute but I had to "Connect" it manually

@Range (0,10000)
attr MEDIAN_HGT = 0 #Should be a GIS Driven Attribute but I had to "Connect" it manually

@Hidden
attr MEDIAN_HGT_feet = MEDIAN_HGT * unitScale

@StartRule
Footprints-->  extrude(MEDIAN_HGT_feet)
               split(y) {MEDIAN_HGT_feet/STORIES:Floor}* #comment this out if you don't want floors/horizontal splits

I also saw something that was odd and - see above - the building has 20 stories, but the Median Height of the building is only 124 feet. So just a point of caution. Another note, the building in the foreground is 4.5 stories, in case you were wondering what was going on with the short top floor.

Hope this helps.

Devin

MichaelNelson3 · Answer

Attached is a copy of the zip files.  I'm using CityEngine 2015.2

Thanks

Bldgs & Traffic.zip