Epic Games Unreal Datasmith (UDATASMITH) Writer Parameters

Dataset

Choose a name for the .udatasmith file within the dataset directory.

If this parameter is left empty, the default name is always scene.udatasmith.

Spatial

Coordinate systems may be extracted from input feature data sources, may come predefined with FME, or may be user-defined. FME allows different output and input coordinate systems, and performs the required coordinate conversions when necessary.

How FME Processes Coordinate Systems in the Workspace

If a coordinate system is specified in both the source format and the workspace, the coordinate system in the workspace is used. The coordinate system specified in the source format is not used, and a warning is logged. If a source coordinate system is not specified in the workspace and the format or system does not store coordinate system information, then the coordinate system is not set for the features that are read.

If a destination coordinate system is set and the feature has been tagged with a coordinate system, then a coordinate system conversion is performed to put the feature into the destination system. This happens right before the feature enters into the writer.

If the destination coordinate system was not set, then the features are written out in their original coordinate system.

If a destination coordinate system is set, but the source coordinate system was not specified in the workspace or stored in the source format, then no conversion is performed. The features are simply tagged with the output system name before being written to the output dataset.

For systems that know their coordinate system, the Coordinate System field will display Read from Source and FME will read the coordinate system from the source dataset. For most other input sources, the field will display Unknown (which simply means that FME will use default values). In most cases, the default value is all you'll need to perform the translation.

You can always choose to override the defaults and choose a new coordinate system. Select More Coordinate Systems from the drop-down menu to open the Coordinate System Gallery.

Changing a Reprojection

To perform a reprojection, FME typically uses the CS-MAP reprojection engine, which includes definitions for thousands of coordinate systems, with a large variety of projections, datums, ellipsoids, and units. However, GIS applications have slightly different algorithms for reprojecting data between different coordinate systems. To ensure that the data FME writes matches exactly to your existing data, you can use the reprojection engine from a different application.

Note  To use this feature, you must have a supported GIS application installed on your system (for example, Esri ArcGIS®).

To change the reprojection engine, Select Workspace Parameters > Spatial > Reprojection Engine. In the example shown, you can select Esri (but the selection here depends on your installed applications):

For more information, see the links below:
  • Yes – Coordinates of all the points in the written features will be offset so they are centered on origin (0,0,0) and scaled to 1 Unreal Unit per centimeter.

Additionally, the transformation matrix required to scale the model back to world coordinates will be written to a companion .fwt file. This can be used to improve precision of the written coordinates. The companion .fwt file will have the same name as the primary data file and will be written in the same folder. For folder-based formats, the file global.fwt will be written instead.

  • No – The original coordinates will be written as provided. Coordinates will not be projected; .fwt world and .prj files will not be generated.
  • Transform Coordinates Only – Transforms the coordinates as in the Yes option, but companion .prj and .fwt world files will not be generated.

Advanced

Some files contain ambient or emissive colors. These colors can, in some cases, cause unwanted visual artifacts to appear on the output .udatasmith file.

  • Ignore Ambient Color – When set to Yes, Ambient Color will be excluded from materials. The default is No.

  • Ignore Emissive Color – When set to Yes, Emissive Color will be excluded from materials. The default is No.

Use these fields to write and preserve additional schema-level information.