topic Re: StreetWidth Used in Setback in ArcGIS CityEngine Questions

StreetWidth Used in Setback

LesiMai — Mon, 07 Jan 2019 15:50:57 GMT

Hi all!

I'm wondering if there is a way to use the StreetWidth attribute so that setbacks can be based on the width of the street the lot side is facing. For instance, if it's a corner lot, I want to have a larger setback for the side that's facing a wider street and a smaller one for the side that's facing a narrower street.

Any pointers will be greatly appreciated! Thank you!

Lesi

Re: StreetWidth Used in Setback

CherylLau — Sun, 12 Dec 2021 07:01:28 GMT

In 2019.0, the new operation setbackPerEdge() allows you to create a setback with different setback distances on each edge. It takes as input a function that specifies the setback distance per edge. The function is evaluated per edge, and comp and scope attributes are accessible within this function.

https://doc.arcgis.com/en/cityengine/latest/cga/cga-setback-per-edge-operation.htm

This code creates a setback where the setback distances are equivalent to the street width on each edge.

attr streetWidth(i) = 0

myFunc = streetWidth(comp.index)

Lot -->
	setbackPerEdge(myFunc) { all: Green | remainder: Red }
‍‍‍‍‍‍

Re: StreetWidth Used in Setback

LesiMai — Wed, 15 May 2019 17:15:52 GMT

Thank you Cheryl for the update on the new functionalities! I'll test it out.

Re: StreetWidth Used in Setback

DavidWasserman — Wed, 15 May 2019 22:25:01 GMT

Cheryl, to clarify, a CE generated lot shape will have access to the street parameters? What about other rule attributes/parameters?

What about imported data?

David

Re: StreetWidth Used in Setback

KZ — Thu, 16 May 2019 10:46:22 GMT

Hi Cheryl

As a follow up on this same question, I'm trying to use envelope and setback function for imported parcels.CE 2019 provided versatility for setbacks, setbackPerEdge documentation showed an example of edge attribute's orientations

dist(orientation) =

case orientation == "park" : 1

case orientation == "street" : 7

case orientation == "lot" : 0

case orientation == "back" : 3

else : 0

My question is how to setup and customise edge attributes for mass data such as the example with parks, streets etc. For envelopes, the front of the envelopes uses street fronts. What I want my front is to be base on compass direction. I tried comp(e) using world.compass direction but the function didn't work. Now with CE2019 my assumption to achieve what I wanted will be using one set of edge attributes to rearrange street orientation for the envelope function and another set of edge attributes for my setback. But could not seem to find any documentation on setting up edge attributes.

Re: StreetWidth Used in Setback

CherylLau — Fri, 17 May 2019 09:52:02 GMT

No, the streetWidth attribute is a special case. See this post:

https://community.esri.com/message/722386-re-designate-multiple-street-edges?commentID=722386&et=watches.email.outcome#c…

Re: StreetWidth Used in Setback

CherylLau — Fri, 17 May 2019 13:31:01 GMT

In 2019.0, you can create custom edge attributes manually in the Inspector by adding new object attributes. Edge attributes must have the prefix /edgeattr/. When creating an edge attribute, choose an array type (BOOL[], FLOAT[], or STR[]) and enter in as many values as you have edges, and terminate each value with a semicolon. After the edge attribute has been created, you can also change a value for an edge in the Inspector by selecting the individual edge.

For example, if I had a triangle shape and I wanted to create an edge attribute for the color of each edge, I would create the following edge attribute.

Edge attributes can also be created using Python using ce.setAttribute.

On non-dynamic shapes (shapes not created by street networks), you can calculate edge attributes for each shape using the built in menu option (Shapes -> Compute Edge Attributes). This uses the nearest streets to calculate information like /edgeattr/orientations, /edgeattr/streetcategories, and /edgeattr/streetwidths.

https://doc.arcgis.com/en/cityengine/latest/help/help-compute-attributes.htm

In CGA, you can access these edge attributes using edgeAttr.getFloat(), edgeAttr.getString(), edgeAttr.getBool().

https://doc.arcgis.com/en/cityengine/latest/cga/cga-edge-attr-function.htm

In the triangle example above, I could color the edges of the triangle using edgeAttr.getString("color").

comp(fe) { all: color(edgeAttr.getString("color")) primitiveCube s('1, w, w) center(yz) Edge. }‍

Re: StreetWidth Used in Setback

DavidWasserman — Fri, 17 May 2019 18:24:19 GMT

Got it. Only on parcels CE generates or also can be associated with a first edge operation?

Re: StreetWidth Used in Setback

CherylLau — Mon, 20 May 2019 07:05:27 GMT

Sorry, I don't understand this question.

Re: StreetWidth Used in Setback

DavidWasserman — Tue, 28 May 2019 16:29:30 GMT

I guess my question is there are two types of "parcels" or "lots" in CityEngine. One generated by outlines of roads, and those imported. I guess my question is how this applies to imported parcels and how one might go about orienting their edges for these operations.

Re: StreetWidth Used in Setback

CherylLau — Wed, 29 May 2019 07:06:15 GMT

The special streetWidth attribute code

attr streetWidth(i) = 0‍

will only work if the shape has an object attribute called streetWidth[] which is an array of floats. This object attribute is automatically generated on dynamic shapes (shapes created by graph networks). This object attribute does not inherently exist on non-dynamic shapes, but it can be created using Shapes -> Compute First/Street Edges.

https://doc.arcgis.com/en/cityengine/latest/help/help-shape-edge-tools.htm