The Ürban PAD template Editors are four graphic design components used to create templates, roads, crossroads, and city blocks (sectors) in Ürban PAD. They include:
Graphic designers can use template Editors to create urban content, while level designers use the City Designer component to build the city using this content. This system promotes parallel workflows within a design team, as it is possible to update city content in real time. For example, a level designer can automatically update a city prototype with a road template that has recently been changed.
The basic unit of Ürban PAD content creation is the template, a file that is created from assets to which Ürban PAD policies have been applied (see policy_intro). Policies are instructions telling the assets how to behave under a certain set of conditions. You can create templates for roads, crossroads, activity parcels, and city blocks (sectors).
These template files are stored in Urban PAD’s .gcf format within a City Project (see What Is a City Project?) and are exportable to Collada, XML, and other standard formats.
A brief description of templates and an outline of the four Editors follow.
Creating a template in any of the four editors involves taking meshes and decals that have been created with 3D modeling software such as Maya or 3DSMax and then imported to Ürban PAD using the built-in Mesh Converter (mesh_conv_tut), which converts them to Urban PAD’s .egg format, and then applying policies to the mesh or decal. A policy is a condition applied to an operation or a combination of operations that tells the object how to behave.
For example, you may want a house to re-scale itself from one instantiation to another. In this case, you could apply a Scaler Expanding Policy specifying that the scale of the meshes composing the house will vary between 0.8 and 1.4 times its current size each time the parcel is regenerated.
You could make the result even more complex by combining this policy with the Select Expanding Policy. You could program the Parcel Editor to choose between two different houses at each regeneration, to each of which the Scaler Expanding Policy would be applied.
The Ürban PAD Tutorials and the Policies section give an overview of the different policies and how they can be used to manipulate graphical content.
Each template is the result of a description that is created in the left-hand portion, or layer window, of the Editor. The layer window is a hierarchical tree showing the template elements and how they are related to each other. Be aware that if you delete a parent object, it will delete all the child objects and the operations associated with them.
One very striking advantage of the Editors is that they allow for instantaneous regeneration of templates.
Each time you create a template, the Editor applies the policies you select to the objects within the template. You can regenerate your parcels instantly. In Parcel and Road Editors, these regenerations take place in the View window of the editors.
Ürban PAD has the advantage of letting you modify the templates, then updating the object directly in City Designer. If a graphic designer changes the size of a building and the level designer needs to see how this affects the available sector space in City Designer, the level designer can regenerate the new or updated object in City Designer as soon as the graphic designer has finished editing it. This capacity accomplishes the twin objectives of speeding up workflow and smoothing out your pipeline.
With these basic features in mind, let’s move on to a brief description of each Editor.
The Parcel Editor is used to create Ürban PAD activity parcel templates. An activity parcel template is an graphical object that is forms the basis of an urban activity in City Designer. An object can be a house, a car, a trash can, or a group of trees.
The Parcel Editor interface consists of a hierarchy tree and a workspace. The hierarchy tree provides a written description of the visual elements that appear in the workspace, so you may edit your templates directly in the workspace or in the hierarchy tree.
The Road Editor is used to create road templates, which form basis of the road networks used in City Designer. You design one or more templates using the same features that are present in Parcel Editor. The interface is similar, with a workspace and a View mode for instantiating the results of your road parcel description.
The Crossroad Editor is used to create crossroad templates. These templates can be associated automatically with road templates created in Road Editor, enhancing the automation of your city creation.
Sector Editor is used to create sectors, or city blocks. In Sector Editor, you will define the decorations, textures, and walkways of your city. During the city generation phase, City Designer fills up the sectors with activity parcels created in Parcel Editor.
City Designer is Ürban PAD’s procedural city generation engine. See createcity25 for a tutorial on creating a city in Ürban PAD 2.5. The tutorial includes an overview of:
You may save the resulting city file as a .dae, .gcf, or .xml file and store it in your City Project cities directory, or export it to a game engine.