Format Deprecation Notice: This version of the FME AR Reader/Writer is deprecated in FME 2021.1+. Workspaces created before this version will still work until the format is removed from FME, but consider updating to the improved version of this format: FME Augmented Reality (FME AR) Writer.
The FME Augmented Reality (FME AR) Reader/Writer enables FME to access FME AR files can be loaded into the FME Augmented Reality app on certain iOS and Android devices.
Overview
An FME AR file consists of a package of several OBJ and Material files that define a collection of 3D geometries that can be displayed using the FME Augmented Reality (FME AR) app.
FME AR files always contain three-dimensional geometry. Two-dimensional data will be represented with one of the coordinates (usually y or z) being 0.0 for all geometry.
Reader Overview
The FME AR reader produces FME features for geometry data in an FME AR file. The FME AR reader extracts all the geometry in an FME AR archive and then presents the elements one at a time to FME for further processing. Each .obj asset in the file will create an FME feature type and produce a single feature.
The value for the Reader Dataset is the path to the FME AR file.
Writer Overview
The writer creates and writes feature data to an .fmear file.
An existing .fmear file in the folder is overwritten with the new .fmear file with the same name. If the .fmear file cannot be written, the translation fails.
The value for the Writer Dataset is the path to the output file.
Each feature type written to an FME AR writer will create a separate asset within the output .fmear file. Texture and material information will be combined into a single material library, and all texture sources will also be packaged into the .fmear.
Feature type fanout is supported.
Coordinate System Projection
If the FME AR writer receives features with coordinate systems, it reprojects the data into the azimuthal equidistant projection (AZMED). The writer reprojects the entire model – not feature by feature or feature type by feature type.
Note: The AZMED projection ensures that all points on the map are at proportionally correct distances from the center point, and all points on the map are at the correct azimuth from the center point. In an AZMED projection, the Y axis points to the north, and the X axis points to the east. If the model rotation is important when loading in the FME AR app, you should ensure that the axes are correct.
If the FME AR writer receives data that does not have a coordinate system, it first assumes the data is in meters, and then also reprojects the data into AZMED (which means the model is shifted so that 0,0 is in the center of the model).
Converting 2D Features to 3D
When working with 2D data, the coordinate system units become critical to note.
Some coordinate systems, such as LL-WGS84, express the X and Y coordinates in degrees, while the Z coordinates will be in meters. Using a 3D bufferer to create pipes from lines will behave unexpectedly here, as the X and Y units will not correlate the Z units, and may appear flattened.
When performing operations such as buffering or scaling, it is recommended (for consistency) to reproject to a coordinate system that uses the same unit for all axes.
Terminology in this Chapter
|
Term |
Definition or FME Representation |
|---|---|
|
Anchor |
Position in the world that the model should be placed, in LL84. |
|
FME AR file |
A package of several OBJ and Material files that define a collection of 3D geometries that can be displayed using the FME Augmented Reality (FME AR) app. |
|
Reader Dataset |
The path to the FME AR file. |
|
Viewpoint |
A 3D point that acts as a spatial bookmark. It enables the viewer to quickly view the model from this point when using a supported phone app. |
|
Writer Dataset |
The path to the output file. |