topic Re: Variables storage in ArcGIS CityEngine Questions

Variables storage

TalAisenberg — Tue, 03 Apr 2012 13:34:02 GMT

Hey,

Is there a way to store a value at some point in the code so I can use it later - for example:
I want to determine a building's height based on the plot size and its footprint (in order to get my FAr right). So I need to:

1. Measure the plot - geometry.area and save it
2. create the building footprint with ShapeL (or offset / ShapeU....)
3. now calculate based on a target FAR the height of the building (FAR = plot area / (footprint * no. of stories))
4. extrude the building to the required height

Its just that once I've done the shapeU operation I cannot go back to read the plot area as geometry.area(bottom) will now give me the building footprint.

I tried with assigning the value to a new attr on the Lot rule (just before I divide them) but this doesn't seem to work.

Cheers
T

p.s. working with really tedious urban planners - you know how they can sometimes be 😐

Re: Variables storage

AndréCardoso — Fri, 10 Dec 2021 21:35:01 GMT

I'm not sure what you have tried to do already ... but have you tried to use the "set(attr, attrValue)" function?

Something like this:

@Hidden
attr originalArea = 0

Lot -->
   print("Original Area", geometry.area)
   set(originalArea, geometry.area)
   BuildShape

BuildShape -->
    shapeL(3, 4){shape: ShapeRule | remainder: NIL}

ShapeRule -->
   alignScopeToAxes(y)
   print("Original Area Again", originalArea)
   print("Current Shape area", geometry.area)
   extrude(world.y, originalArea/8) # calculate height in function of oriignal footprint area
   Shape.

Does it work?

Re: Variables storage

AndréCardoso — Fri, 10 Dec 2021 21:35:03 GMT

Another possibility is just to pass the original area down to the next rules, as Rule parameters...

Lot --> 
Rule2(geometry.area)

Rule2(area) -->
Rule3(area)

...

Re: Variables storage

TalAisenberg — Wed, 04 Apr 2012 07:34:43 GMT

Brilliant, Set does the trick.

The problem with the second option is that I only need to use the variable in routines 4 or 5 levels down so bit cumbersome to pass it on and on.

Thanks again,
T

Re: Variables storage

AndréCardoso — Wed, 04 Apr 2012 07:42:37 GMT

Exactly! For me, one the great things added in these recent versions of CE was the capability to use "set()" with attributes defined by us. Things get much cleaner...

🙂