Game Development Reference
In-Depth Information
Scaling and units.
You'll want to avoid any unnecessary scaling of your objects
when importing FBX files into your game engine. If you import a scene into your
game engine with a scale factor already applied, it can quickly get confusing to work
within the game engine's units once additional scaling of the object is applied.
This confusion can be avoided by simply working in and exporting to the unit
system of your target application or game engine. For instance, since Unity's system
unit works in meters (its physics system assumes that 1 unit is equal to 1 meter),
you'll want to work in meters in 3ds Max. Do not adjust Display Units in 3ds Max;
it's best to keep them generic. 3ds Max uses inches as its default System Units
setting. You can change this by simply going to the Customize menu, to the Units
Setup dialog and setting your System Unit Setup to 1 unit = 1 meter, in this case.
From thereon in, you will be exporting to the FBX file format in meters by default
(since the unit system in the default FBX exporter dynamically adjusts to match
your host application's unit settings), thereby retaining its 100% scale. Once that
scene is imported, the scale remains unmodified at 100% (or (1
1)).
If you cannot change the unit system of your DCC or simply choose not to, that's
fine as well. In Maya and MotionBuilder for instance, the default system unit is
centimeters and is again your choice whether or not you adjust the unit setting in
the host application or apply a scale to the FBX objects being exported. You will
simply need to disable the Automatic option in the Unit settings rollout found in
the Advanced Options rollout of the FBX exporter and set your units to match
those of your target application. Most game engines will adjust this automatically
for you during the import process, but it's good practice to export to the proper
unit system in case your specific game engine importer doesn't recognize a file's
scale factor.
Any objects exported to a different unit system will be scaled; that is to say
that the vertex positions of all objects in the scene remain the same while the local
scale of the object changes. For instance, a 1 cm cubed box will export out of 3ds
Max to FBX in meters as 1 unit cubed with a scale factor of 0.01.
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1
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22.2.5 Embedded Media
It's common for game developers to import scenes without embedded media into
a game engine and afterwards apply the media, but this isn't necessary. You will
most likely want your exported FBX files to be portable and self-contained, in that
everything you need in that file is in the file and not located on another path on
your hard drive. If all related media is contained within an FBX file, opening that
scene anywhere else (i.e., on another computer) removes the hassle of having to
research the locations of those missing texture files that are no longer in the same
location. A lot of time is saved and confusion avoided when you choose to embed
all media of a scene when exporting to the FBX file format.
To embed media during the FBX export process, simply select the Embed Media
option found in the Include rollout of the FBX exporter. All image files associated
