Python code: Selecting all objects with one attribute

[AlexWierzbicki]

Hoping that someone can help me out. I am a python newbie and I am trying to create a script that will select all objects that have the Object Attribute "amenity" equal to "school". Could some please help me identify what is wrong with the below code? 

from scripting import *

# get a CityEngine instance
ce = CE()

def selectByAttribute(attr, value):
    objects = ce.getObjectsFrom(ce.scene)
    selection = []
    
    for item in objects:
        attribute = ce.getAttribute(item, attr)
        if attribute == value:
                selection.append(item)
        
    ce.setSelection(selection)

if __name__ == '__main__':
    selectByAttribute("/ce/geometry/amenity", "school")

[MJF]

Remove /ce/geometry/ and it should work

selectByAttribute("amenity", "school")

[JonasObertuefer]

Hi @AlexWierzbicki,

For a python newbie you got already quite far 😉

For object attributes you don't need any prefix just write selectByAttribute("amenity", "school") and your script should work.

I suggest two other small improvements to your script:

• Add @noUIupdate before your function. This makes sure the UI will be refreshed only after the function is run through. Depending on the size of the scene and what your function does this can speed up the run significantly
• In your case you don't need to query all objects from the scene, you can limit it to shapes only if you write objects = ce.getObjectsFrom(ce.scene, ce.isShape)

Cheers,
Jonas

[AlexWierzbicki]

I've made the suggested changes but unfortunately it is still not working, receiving either the following error or nothing at all happening, depending on where I put the @noUIupdate

Below is the code. Any other advice? 

from scripting import *

@noUIupdate

# get a CityEngine instance
ce = CE()

def selectByAttribute(attr, value):
    objects = ce.getObjectsFrom(ce.scene, ce.isGraphSegment)
    selection = []
    
    for item in objects:
        attribute = ce.getAttribute(item, attr)
        if attribute == value:
                selection.append(item)
        
    ce.setSelection(selection)

if __name__ == '__main__':
    selectByAttribute("amenity", "school")

[JonasObertuefer · Accepted solution]

hi again,

• @noUIupdate needs to be directly above the function you want to trigger no UI updates
• change the filter in your getObjectsFrom() from ce.isGraphSegment to ce.isShape. Amenity is isuallay a object attribute assigned to shapes.

I tested the the code below, and it works for me:

# get a CityEngine instance
ce = CE()

@noUIupdate
def selectByAttribute(attr, value):
    objects = ce.getObjectsFrom(ce.scene, ce.isShape)
    selection = []
    for item in objects:
        attribute = ce.getAttribute(item, attr)
        if attribute == value:
                selection.append(item)
    ce.setSelection(selection)

if __name__ == '__main__':
    selectByAttribute("amenity", "school")