8 Steps to Building a CUBE Model



This article highlights the main steps to get you started using the CUBE 6 software from scratch. It answers the main questions a user needs to answer when approaching a new software, and highlights the main components of a CUBE model by going through the main 8 steps to set-up a model from scratch with CUBE:

Getting Started with CUBE and Building Your Model from Scratch 

When approaching a new software, and specifically our CUBE software for Land Use and Transportation Modeling, we want to be sure that we are undertaking the correct steps to get started and being able to use the software properly. We generally have the following questions:

  1. How do I obtain a license, where do I download the software and how do I install it correctly?
  2. What does the interface look like and where do I open the different windows that I need?
  3. Where can I find help in using the software? (e.g. training courses, demonstration models and useful examples and tips?)
  4. What are the input data that I need, and what about their format?
  5. How do I build a model from scratch and what are the main components of my model?

This article will guide you through the answers to the above 5 questions and take you to the point of being able to start building your own models!

1. SOFTWARE INSTALLATION

First of all, a valid license is necessary. This could be a temporary license for evaluation purposes, or a purchased license. Both these types of license can be requested from our sales team via the form here or on our virtuosity site here. Please feel free to ask us any question on this, we are always happy to help finding the most suitable solution to your needs.

Once you have obtained the license you desire, you can download our software from our Download Page. If looking for information on Connect and CUBE together with detailed instructions on how to install the software then please see here.

2. OPENING UP CUBE AND CUBE INTERFACE

Double click on the CUBE icon in our desktop to open up CUBE…

When you open up CUBE for the first time, after a successful installation and activation of the license, the CUBE Welcome Window looks like below:

 Cubetown Demo Model

If interested in having a look at a Demonstration Model we recommend downloading checking Cubetown. Click here to download “Cubetown” demonstration model and find more information about it.

The CUBE Voyager Demo Model is a 25-zone “4-step” Voyager passenger demand forecasting model with feedback to trip distribution. The following applications are also available within the same catalog:

CUBE Base is the user interface for the entire CUBE system and provides interactive data input and analysis, GIS functionality through the ArcGIS engine, model building and documentation, and scenario development and comparison. Links between the model, the data, and GIS are a single click away, making the development and application of models easy to use.

 

 

3. HELP IN USING THE SOFTWARE

The best way to get quickly up to speed with CUBE is to undertake one of our training courses. We run training courses online. Please find more details here.

Several “help-channels” are available for current users or users that are evaluating the software, they are directly available by clicking on the question mark (top right corner) of you CUBE window.

 

Interactive Manuals and PDF Documentation on the different modules (Analyst, Analyst Drive, Cargo, etc.)



If you have any issue in using the software or need technical assistance, you can also raise a service request via the Bentley Connection Center. Go to Bentley Support

 


Click on Go to Connect Center and enter your credentials, scroll down to My Service and select New Service Request

An Open Forum for users is also available at the link. 

4. INPUT DATA AND FORMAT

Zonal data, record data, matrices and networks with different formats can be processed in CUBE (text files, DBF files, ESRI shape files, geodatabase tables and datasets).

CUBE exploits the availability of a complete transportation GIS based on ESRI’s leading technology dealing directly with geodatabases and shape files. Conversion from and to these formats is direct in CUBE Voyager, and common practice is to use geodatabases (file - GDB, personal - MDB) for storing data and directly reading and writing to and from them in the modelling steps.

CUBE also has its proprietary binary formats for the main “ingredients” of the model, allowing reduced disk storage requirements, and storing large data in light files for faster processing of input/output.

5. BUILDING MY MODEL STEP-BY-STEP

We can identify 8 main steps that we can follow to build our model in CUBE from scratch. They are explained here below.

1ST STEP: CREATE THE FOLDER STRUCTURE

The preliminary step when building your model is to create a folder to store all your model files, this folder is called the “catalog folder” (e.g. “TrainingModel_Structure”). Indeed, we refer to a CUBE model as a “catalog”, as we will understand in Step 2 when talking about the catalog file.

Inside the catalog folder, we should create the folder structure for our model, defining some subfolders storing specific files. The folder structure is completely up to the model developer. An example is provided below, with the sub-folders:

It is important that all the files used inside your model are stored in the catalog folder (within the specific sub-folder), in this way every time that you copy the entire TrainingModel_Structure folder all the links in your catalog will be automatically updated and your model will work properly.

Therefore, start with locating your input files within your Input folder (input network, input matrix, …) and locate your "media" files within the Media folder (banner, images, …).

2ND STEP: CREATE A NEW CATALOG 

The Catalog File (.cat) is the only file which you must remember its name and location. The Catalog File is indeed the ‘root’ of a model, and everything else is linked to it.

The Catalog tracks the major components of your model:

To create a new catalog:

Save the new Catalog within your main catalog folder with a name that represents your model (e.g. \TrainingModel_Structure\Training_Model.cat)

 

 

3RD STEP: CREATE A NEW APPLICATION

The Applications are the Model Processes saved in a file with extension .app. A single Catalog may have many Applications (e.g. Passenger Forecasting, Freight Forecasting, Land-Use Forecasting, Sub-Area Analysis, Impact Studies, etc.).

The Application file is a single page that tracks data flows and organizes modeling functions. These functions may be either from CUBE Libraries or User Defined.

To create a new application:

 

In order for the Catalog to track the Application, it must be added to the Application Window, therefore:


4TH STEP: DESIGN THE FLOW-CHART OF YOU MODEL WITH SUB-APPLICATIONS

Applications may be nested to provide the model flow-chart structure using sub-groups. Sub-groups are Application files nested in the “Parent” Application (at the upper level), and they may contain other sub-groups.

Input and output files can be made public to make them visible and available at the “parent level”:

 

It is suggested to properly include sub-groups within your parent applications, splitting the model in different steps depending on the specific task undertaken by the sub-groups. This allows to:

To add sub-groups in your flow chart process:

 

To enter a sub-group, just double click on it, or click to the sub-application name in the App Window. To go back to parent you can right click and select “Go to Parent”, use the “Go to Parent” button in the ribbon, or press F9 as a short cut.

5TH STEP: USE CATALOG KEYS FOR SCENARIO SPECIFIC INPUTS

Catalog Keys are the inputs to the model that are unique for each scenario and are tracked by the scenario manager. The Catalog Keys may be numeric variables, file names, or text strings.

The model applier and model developer modes can be set for the catalog (setting through Files > Options). The Catalog Keys are available to the model applier to be accessed and changed through the Scenario Panel (image below – can be open by double clicking on the specific scenario in the Scenario Manager window). These keys can be reserved to the developer if the intention is to have their values scenario specific but not accessible to the model applier. The model developer defines both keys and the user menu (Scenario Panel).

Catalog Keys can then be used within the script of the CUBE programs or within the definition of the inputs/outputs (e.g. an input network for a CUBE Voyager program can be linked to the specific catalog key). They can be identified in the process by the usage of curly brackets {Catalog_key_name}.

To create a new catalog key (e.g. to store your input roadway network):

 


Double-click on the ‘Base’ scenario to see the new addition to the user interface and select the proper input (e.g. dataset from a geodatabase)

A few suggestions on the usage of catalog keys:

6TH STEP: INCLUDE PROGRAMS TO ACHIEVE MODELING TASKS

We refer here to CUBE Voyager programs, but the other modules available (Land, Avenue, Analyst, Cargo) have a very similar structure and can be included in the process with a similar methodology and similar properties.

CUBE Voyager has been designed to be an integrated modelling system for transportation planning applications.

CUBE Voyager is a library of programs that employ a flexible control language that allows the user to write the script to provide instructions for performing all types of transport modelling operations or data processing tasks.


Each program has a specific function and structure. The programs available within the CUBE Voyager module are the following:


By clicking one of these programs you include it within the Application Manager flow-chart, for example:

 

A program has input files, output files, and an execution order:


Every program has two key files:

 

 


7TH STEP: LINKING INPUT DATA FILES

Data can be linked as input to a program through Application Manager in the four ways listed below. Right click on the input file you want to include to reach the first three options:


The fourth option is creating a direct (dynamic) link between program files by simply highlighting the output file you want to connect ‘from’ and then click and drag a link to the file you want to connect ‘to’. This could be done within the same sub-group or between sub-groups.

 


8TH STEP: ADDING SCENARIOS

To add a new scenario you just need to right click on the scenario name and select “Add Child” or “Add Sibling” depending on the level at which you want to add the scenario (note that “Add Child” only is available for the Base scenario).


A new scenario specific sub-folder will be created inside the parent scenario folder (e.g. Scenario_1 sub-folder inside the Base scenario folder).

An internal catalog key named {Scenario_Dir} stores the path of the scenario specific folder (allowing to link inputs or outputs to this scenario specific location).

These 8 steps guided you through the set-up of your own model! You can find much more details and additional guidance on the different elements highlighted above in our CUBE Base Reference Guide. Details on scripting for the different CUBE Voyager programs can be found in the CUBE Voyager Reference Guide.