IM files

IM Files are the mesh files that display all solid objects in Trainz.

Indexed Mesh files were developed by Auran as part of the Auran Jet gaming engine that is used in the Trainz Simulators.

The IM file contains all of the geometric and texture mapping data needed to render a solid object.

Any surface or solid object can be rendered as a series of triangular facets. The IM file stores the 3d x,y,z coordinates of all the facets and the texture mapping data to allow the object to be displayed with the correct surface colours. The separate texture images are referenced by the mesh to achieve this.

Indexed Meshes are generated by the exporter plug-ins provided by Auran for 'GMax' and '3DSMax'. The content creator builds the model in GMax/3DSMax and exports the IM file for use in Trainz. See Exporting with 3D Studio Max for an example of this. Additionally an exporter is available for the free program, 'Blender'. Auran's 'TrainzMeshImporter' is used, in this case, to create the IM file from an intermediate XML file.

Auran provides no editing or manipulation programs for Indexed Meshes, and third party progammers are requested not to alter mesh files. If any changes are needed, the mesh creator must do it...

There is no need for the Trainz user to know the workings of the IM file, so no further data is provided here.