About Coordinate Systems and Model Extents

Coordinate Systems and InfraWorks

Each InfraWorks model uses a coordinate system to position your data, allowing you to rapidly create and evaluate multiple design alternatives in a real-world context. Changing the coordinate system can affect how the data can be exchanged with other application, such as Autodesk Civil 3D or ESRI ArcGIS.

Note: the coordinate system for an InfraWorks model is different from the Display coordinates, a.k.a user coordinate system (UCS), which is only used to modify the coordinates shown in the Status Bar. The UCS is essentially a display coordinate system, and does not affect how model data is stored or displayed.

Model Creation and Coordinate Systems

You are required to specify a coordinate system when you create a new model. The coordinate system you select for a model cannot be changed once the model has been created. By default, InfraWorks model extents are initially set to the boundaries of the model's coordinate system.

See To create a model manually.

In some cases, you may need to recreate an InfraWorks model and assign a new coordinate system. See To recreate an InfraWorks model with a new coordinate system.

Which Coordinate System Should I Choose?

If you plan to exchange data between a InfraWorks model and other Autodesk applications such as Autodesk Civil 3D or Autodesk Revit, you must create your Infraworks model with a projected coordinate system (not a geographic coordinate system like LL84).

Coordinate Systems and Data Import

When you import data that uses a different coordinate system than your model's coordinate system, InfraWorks translates the imported data and re-projects it using your model's coordinate system. In rare cases, data that you bring into your model may not display properly if it was assigned the incorrect coordinate system(s) during configuration. This normally only occurs when you bring in 3D model data that uses a custom coordinate system with no world file.

See to specify the coordinate system during import.

During export, you can specify a desired target coordinate system that will be assigned to model data. By default when you choose Export IMX or Export FBX, InfraWorks will select the best fit it can find for the extent of the export area, and will assign that coordinate system to the exported file.

For example, a model located in northern California, western Oregon, or Washington state in the United States would likely be assigned a UTM84-10N coordinate system during IMX export. A model located in Tokyo, Japan would likely be assigned UTM84-54N during IMX export. To address this, make sure to select the appropriate target coordinate system for exported data, so that the coordinate system matches your desired use of exported model data outside of InfraWorks.

Some other products will have difficulty recognizing some of the coordinate systems you may be using in InfraWorks. For instance, Autodesk AutoCAD Civil 3D has difficulty recognizing and translating InfraWorks models that use geographic coordinate systems such as LL84. If you export an IMX file from InfraWorks to be used in AutoCAD Civil 3D, specify a target coordinate system that matches the coordinate system that will be used in the Civil 3D drawing.

Some coordinate systems are not supported when publishing to ArcGIS or exporting to FGDB. If a model is assigned an unsupported coordinate system, publishing to ArcGIS or exporting to FGDB will not proceed.

Model Extent

When you create a model manually, you can specify model extent during model creation to define precise geographic boundaries for your model. If you do not specify model extent, the boundaries of the model's coordinate system will be used as the default model extent. If you create a model with Model Builder, your model extent will be defined by the area of interest you specified when creating the model in Model Builder.

See To create a model manually or create a model with Model Builder.

Once a model has been created, you can manually modify model extent in the model properties dialog. See To change model properties for more information.

After you have defined the model extent for your base model, you can choose limit the geographic extent of imported data for most feature classes using the Source tab of the Data Source Configuration dialog (this is not an option for 3D models that you import). Double click on a data source in the Data Sources panel and choose Clip to Model Extent from the Source tab. This will limit the extent of imported data to the already defined model extent. See To specify source and draping options for more information.

Note: A single model can span all UTM zones, while maintaining accuracy in measurement and representation. If you do not explicitly define a model extent as you import data, the model extent will grow to include the extent of all imported data sources, which can increase disk space requirements for the model and may reduce performance if additional data sources have a larger extent than the base model. To improve performance and save space, define a smaller model extent as you create a new model.