Export FBX (Autodesk)

Autodesk FBX is a proprietary 3D geometry exchange format with a freely available SDK. It has recently gained popularity again as the main exchange format for the Unreal and Unity game engines and related AR/VR applications. It is currently lacking in terms of modern material support (e.g. PBR) and metadata transport, but efforts are underway by Autodesk to improve this. For non-AR/VR use cases, we recommend glTF instead.

Export settings

In addition to the general export options, FBX has the following options:

Create Shape Groups

If enabled, a transformation node is inserted for each shape (i.e. building). Meshes will not be merged by material across shapes.

Embed Textures

If enabled, textures are stored inside the binary FBX file.

CGA Mapping to FBX

/As the FBX file format is quite verbose, here are some selected examples for this manual. Please refer to the documentation provided by Autodesk (http://www.autodesk.com/products/fbx/overview).

Geometry and transformation data


The pivot is in the origin; the scope (yellow) contains a translation and a rotation.

FBX Import Autodesk Maya

Exported scene via FBX in Autodesk Maya. Both "One Mesh Per .." options have been disabled to avoid merging any assets. In this case, each asset is parented to a transformation node. Else, the transformation is applied to the vertices.

Multi-texturing and layered texture nodes


The CityEngine material model multiplies all color textures (color- and dirtmap, if present) with the diffuse color. This example displays the layering/multiplicaton of "colormap" and "dirtmap".

FBX Import Autodesk Maya

For FBX, CityEngine exports multiple textures as "layered texture nodes" whose blend modes are set to "multiply".

Working with per-texture transformations


The CityEngine features material attributes to scale, translate and rotate textures independently of the actual texture coordinates stored inside the assets:

  • material.{...}.tu/tv = translate/offset texture
  • material.{...}.su/sv = scale/repeat texture
  • material.{...}.rw = rotate texture around face normal

FBX Import Autodesk Maya

Upon FBX import into maya, CityEngine's tu and tv attributes are mapped to the "Offset" parameter of maya's place2dTexture nodes, su/sv are mapped to the "RepeatUV" parameter and rw is mapped to the "Rotate Frame" parameter.