Looking to convert all single valence node crossings into roundabouts

[NateSkeen]

I'm not sure what the best way to go about this would be. I'm thinking it should be a simple conditional rule that converts the shape's type to roundabout if its corresponding node has a valence of one, but I just started getting into CityEngine a few days ago and am still grappling with CGA. Is there a way to control shapes based on their underlying graph properties?

Thank you for any help in advance!

[ThomasFuchs]

Hi Nate,

Thank you for this question.

The CGA street rules work on CityEngine dynamic shapes and their attributes.

By changing the underlying graph properties, the shapes are automatically regenerated.

Here is a Python script to accomplish this task:

'''
Created on Apr 23, 2018

@author: ESRI R&D Center Zurich 
'''
from scripting import *

# get a CityEngine instance
ce = CE()

def findDeadEnds(nodes):
    deadEnds = []
    for node in nodes:
        if ce.getAttribute(node,'valency') == 1.0:
            deadEnds.append(node)
    return deadEnds      

if __name__ == '__main__':
    
    # get selected nodes
    nodes = ce.getObjectsFrom(ce.selection(), ce.isGraphNode)

    # get all dead end nodes
    deadEnds = findDeadEnds(nodes)
    
    # set all dead ends to 'Roundabout'
    ce.setAttribute(deadEnds, '/ce/crossing/type', 'Roundabout')
    ce.setAttributeSource(deadEnds, '/ce/crossing/type', 'USER')
    
    pass‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍