Understanding the Pompeii Example

GregDowning

I am trying to understand the Pompeii Example that I downloaded.

If I open the file w/ out automatically generating the models I an reproduce the same results using the supplied traced footprints by selecting the lots, choosing the Pompeii.cga using the "Footprints" start rule and generating the models.

I get similar successful results when selecting the Streetnetwork that comes w/ the file.

However If I grow my own street network and apply the same rule and start rule and generate models I only get the courtyards w/ trees. You can see a comparison in the image below on the right you can see the streetnetwork that came with the file. On the left you can see the result I get when growing a streetnetwork myself. I have tried adjusting all the street patterns, many of the setting and all of the block settings.

[ATTACH=CONFIG]23107[/ATTACH]

The only consistent difference I have noticed between the streets I have grown versus what is supplied w/ the file is that the one that came w/ the file has more lots and they are highly varied in size, also many of the lots are much smaller. This leaves me w/ a few questions.

1. Is it the difference in lot size and variation that is causing the variation in building types?

2. If so, how do I get these variations?

3. Is that a way to inspect exiting street networks and see how it was produced?

4. Are there any docs describing this example in more detail?

street_compare.jpg

SlopeDegree.JPG

NicolasGIS_2-1783325366225.png

MatthiasBuehler1

Hi !


1] yes :

Check code lines 21 - 25 in 'pompeii.cga' :

attr atrium    =  case geometry.area > 250   : true  case geometry.area > 200 && p(0.75) : true  case geometry.area > 150 && p(0.50) : true  else 

And line s 243, 244 :

Footprint -->  case !atrium :

Actually check also lines 219 - 241 and make sure you control the Start Rule.

The dynamic blocks have the StartRules 'Lot' and 'LotInner', the default ones. The ones which are set to be generated once you open the scene have Start Rule 'Footprint.

Based on the code you see that 'more or less', it does not matter if the shapes is a Lot, LotInner or Footprint, which means that the Atrium creation is triggered based on the area of the shape.


2] Alter the Block Subdivision ( Lot Sizes ).
Learn about this in the first 2 tutorial videos :
http://forums.arcgis.com/threads/64843-CityEngine-Collection-RESOURCES-FAQ-HELP

Not sure if I understood this question right though .. 🙂

3]
After you have grown streets, they're set. Either undo or delete or edit them otherwise.

When using the 'Dynamic City Layouts' system as you're doing, street segments and street nodes are the 'parent nodes', shapes are thir children. Some attributes are inherited down, e.g. StreetWidth. You see that it's inherited in the Inspector by the fact that the value is written italic.

4] Not really ..
But here I am and have nothing else to do .. *cough* 😮


Cheers !

M.