topic Re: City Engine Get Object attribute in ArcGIS CityEngine Questions

City Engine Get Object attribute

JohnEsther2 — Wed, 24 Jul 2019 14:05:22 GMT

City Engine Get Object attribute to use as the rule default is not working.

attr streetWidth = getObjectAttr("width")

used to work perfectly but now in ce 2019.0 it is telling me that:

Unused function:streetWidth
No such function: ? getObjectAttr(a:str)

what is the issue?

Re: City Engine Get Object attribute

LR — Sun, 12 Dec 2021 08:16:24 GMT

Try

attr quack = "" # this is your object attribute, might want to @hidden
attr whatgoes = quack

@StartRule 
 Lot --> 
 	 print(whatgoes)‍‍‍‍‍‍

Re: City Engine Get Object attribute

JohnEsther2 — Thu, 01 Aug 2019 10:16:46 GMT

Thanks L R. That was helpful. this will enable me to script the attributes with python

Re: City Engine Get Object attribute

CherylLau — Thu, 08 Aug 2019 14:59:52 GMT

getObjectAttr() does not work in cga rule files. It is meant to only work in layer attribute code, which you can see in the Inspector when selecting a layer. Code can be manually entered here, but it is more likely that it will be automatically entered here when connecting rule attributes to layer attributes.

L R's suggestion is a good way of getting values from an object attribute into a rule attribute with a different name. I would go with this. However, I want to describe another method so that I can give an example of how getObjectAttr is used.

Another way of doing this would be to connect your rule attribute to the object attribute through the layer. Click on the drop down box next to your rule attribute in the Inspector and select Connect Attribute.

Then, connect through a layer attribute, and select the layer and name of the object attribute.

Then, if you select the layer, you'll see that the Layer Attributes section in the Inspector contains the code:

attr a = getObjectAttr("b")‍

Note: getObjectAttr() will most likely be deprecated soon to be replaced by separate functions for floats, strings, and bools. The above automatic behavior is expected to work, but the code generated will use the new functions instead of the deprecated one.