Game Development Reference
In-Depth Information
bones, animations, image map channels, hardware shaders, and materials can be
retained when exporting to FBX for use in certain game engines.
Materials.
For great results with materials, you'll want to stick with standard
materials and common map channels. The 3ds Max FBX exporter can support
the following map channels when applied to a standard material: ambient color,
diffuse color, specular level, glossiness, self-illumination (i.e., lightmaps), opacity,
bump, reflection, and displacement. The Maya FBX exporter can support the
following material attributes in a standard Phong material: color, transparency,
ambient color, incandescence, bump mapping, diffuse, cosine power, specular color,
reflectivity, and reflected color.
Geometry.
Geometry needs to be triangulated to be renderable in a game engine.
It's a good idea to avoid letting the renderer do the triangulation itself. In some
cases, it's better to leave this triangulation process up to the game engine's importer
(rather than triangulating the meshes yourself in the DCC).
Your polygon count in your DCC will usually not be exactly equal to what's
being rendered in your game engine; the count will most likely grow on its way
to the final render. Sometimes this is simply because some materials require the
mesh's triangles to be sent to the renderer twice. The more hard edges found on
your geometry, the more triangles will be used to display the mesh in the renderer.
If you want to get a good idea of how many triangles are going to be rendered,
you can collapse your modifier stack in 3ds Max to an editable mesh object that is
a triangulated mesh object and view the face count. Editable meshes are exported
as such using the 3ds Max FBX plugin.
Editable poly objects in 3ds Max are exported as polygonal meshes with hidden
and visible edges; in other words, they are not necessarily composed of triangles.
Editable poly edges that are identified as hidden can be turned by the user, but
the FBX Exporter plugin for 3ds Max will not retain the direction of these turned
edges. This means that if you edit the hidden edge direction of an editable poly
and export that geometry to FBX, the topology most likely will not be written to
file properly.
The 3ds Max FBX Exporter will identify when there are turned edges and
convert the editable poly to an editable mesh during the export process. Edge
directions are retained by triangulating the mesh and baking/exposing all hidden
and visible edges. To avoid the automatic triangulation of your mesh during the
export process when hidden-edge modifications are detected by the plug-in, disable
the Preserve Edge Orientation option found in the Include rollout of the FBX
exporter.
You need to activate the option to Export Tangents and Binormals in the Maya
and 3ds Max FBX Exporters if you want that information saved to FBX and later
imported into a game engine. This avoids having the importer generate tangents
and binormals on its own, using generic and potentially inaccurate user-specified
