Exporting FBX files from Unity

Use Export To FBX (menu: GameObject > Export To FBX) to manually export GameObject hierarchies to an FBX file. The FBX Exporter exports selected objects and their descendants to a single FBX file. However, if you select both a parent and a descendant, only the parent’s hierarchy is exported.

The FBX Exporter exports the following objects:

  • GameObject hierarchies and their transforms
  • Meshes
  • SkinnedMeshRenderers with the following exceptions:
    • Humanoid rigs are not supported
    • Meshes in bone hierarchies are not supported
  • Materials as Phong if the material has specular; Lambert in all other cases
  • Textures
  • Cameras
  • Lights
  • Contraints
  • Animation
  • Blendshapes

Mesh support

The FBX Exporter exports multiple copies of the same Mesh as instances. The FBX Exporter also exports the following mesh attributes:

  • Normals
  • Binormals
  • Tangents
  • Vertex Colors
  • All 8 Mesh UVs, if present
  • Quads or Triangles

Cameras

The FBX Exporter exports both Game Cameras and Physical Cameras.

NOTE: In Unity's Inspector, a Camera's Physical Camera property determines whether it is a Physical Camera or a Game Camera.

Physical Cameras

The FBX Exporter exports Physical Cameras, including these properties:

  • Focal Length
  • Lens Shift

Game Cameras

On export, the FBX Exporter sets the Aperture Height to 0.612 inches, and calculates the Aperture Width using this sensor back relative to the Camera's Aspect Ratio. For example:

* Full 1024 4:3 (1024x768)
   *  Aspect Ratio 4:3
   *  Aperture Width = 0.612 * (1024/768)

The Aperture Width and Height values appear in Unity's Inspector as the Sensor Size property in millimeters.

The FBX Exporter derives the Focal Length from the vertical Field of View (FOV) and the sensor back settings (Aperture Width and Aperture Height). The FBX Exporter uses the default FBX setting for Aperture Mode: Vertical.

Film Resolution Gate is set to Horizontal so that the importing software fits the resolution gate horizontally within the film gate.

The Near & Far Clipping Plane values have a range of 30 cm to 600000 cm.

In addition, the Projection type (perspective/orthographic) and Aspect Ratio are also exported.

Lights

The FBX Exporter exports Lights of type Directional, Spot, Point, and Area.

It also exports the following Light attributes:

  • Spot Angle (for Spot lights)
  • Color
  • Intensity
  • Range
  • Shadows (either On or Off)

Constraints

The FBX Exporter exports these types of Constraints:

In addition, the FBX Exporter also exports the following attributes for all Constraint types:

  • Sources
  • Source Weight
  • Weight
  • Active

Rotation

The FBX Exporter exports the following attributes for the Rotation Constraint type:

  • Affected axes (X,Y,Z)
  • Rotation Offset
  • Rest Rotation

Aim

The FBX Exporter exports the following attributes for the Rotation Constraint type:

  • Affected axes (X,Y,Z)
  • Rotation Offset
  • Rest Rotation
  • World Up Type
  • World Up Object
  • World Up Vector
  • Up Vector
  • Aim Vector

Position

The FBX Exporter exports the following attributes for the Position Constraint type:

  • Affected axes (X,Y,Z)
  • Translation Offset
  • Rest Translation

Scale

The FBX Exporter exports the following attributes for the Scale Constraint type:

  • Affected axes (X,Y,Z)
  • Scale Offset
  • Rest Scale

Parent

The FBX Exporter exports the following attributes for the Parent Constraint type:

  • Source Translation Offset
  • Source Rotation Offset
  • Affect Rotation Axes
  • Affect Translation Axes
  • Rest Translation
  • Rest Rotation

Animation

The FBX Exporter exports Legacy and Generic Animation from Animation and Animator components, or from a Timeline clip.

In addition, the FBX Exporter exports the following animated attributes:

  • Transforms
  • Lights:
    • Intensity
    • Spot Angle (for Spot lights)
    • Color
  • Cameras:
    • Field of View
  • Constraints:
    • Weight
    • Source Weight
    • Translation Offset (Position Constraint)
    • Rotation Offset (Rotation Constraint and Aim Constraint)
    • Scale Offset (Scale Constraint)
    • Source Translation Offset (Parent Constraint)
    • Source Rotation Offset (Parent Constraint)
    • World Up Vector (Aim Constraint)
    • Up Vector (Aim Constraint)
    • Aim Vector (Aim Constraint)
  • Blendshapes (since version 4.1.0)

Animation curve tangents

The FBX Exporter includes the animation curve tangents when it exports an animation.

The only exception is for objects with a prerotation, such as bones of skinned meshes. In that case, the FBX Exporter bakes the curves at each frame, with the prerotation factored out. This ensures that the result matches the original animation despite slight differences between the Unity architecture and the FBX format. More precisely:

  • Unity combines prerotation and rotation, while the FBX format stores them separately. Unity also stores prerotation and rotation data in a single curve.
  • At export, the FBX Exporter separates the rotations into two separate fields: prerotation and local rotation. However, to split the rotation curves in the same way, the FBX Exporter would need to remove the prerotation at each key, which would affect not only the values at each key, but also the key tangents. The FBX Exporter would then need to recalculate them.

Exporting an animation clip from the Timeline

To export an animation clip from the timeline, in the Timeline editor select the desired clip, then from the top menu select GameObject > Export Selected Timeline Clip.

Exporting animations with the FBX Recorder

If you installed the Unity Recorder package, you can also use the FBX Recorder to export animations to FBX files, either from a dedicated Recorder window or through a Recorder Track in Timeline.

Export Options window

When exporting an FBX file, the following Export Options window opens, displaying options for specifying what gets exported.

Export Options window

Properties

Property: Function:
Export Name Specify the name of the FBX file to export.
Export Path Specify the location where the FBX Exporter will save the FBX file.
Source Transfer the transform animation from this object to the Destination transform.

NOTES:
- Source must be an ancestor of Destination
- Source may be an ancestor of the selected object.
Destination Which object to transfer the transform animation to.

This object receives the transform animation on objects between Source and Destination as well as the animation on the Source itself.
Export Format Select the format to use in the FBX file (ASCII or Binary).
Include Choose whether to export both Models and Animation, only Models, or only Animations.
LOD level For level of detail (LOD) groups, choose the desired level of detail to export (all, highest, or lowest).

NOTES:
- The FBX Exporter ignores LODs outside of selected hierarchy.
- The FBX Exporter does not filter out objects that are used as LODs and doesn't export them if they aren’t direct descendants of their respective LOD Group
Object(s) Position Choose whether to reset the exported objects to world center, or keep world transforms during export.

If you select multiple objects for export, and you choose Local Centered from this drop-down menu, the FBX Exporter centers objects around a shared root while keeping their relative placement unchanged.
Animated Skinned Mesh Enable this option to export animation on objects with skinned meshes.

If unchecked, the FBX Exporter does not export animation on skinned meshes.
Compatible Naming Enable this option to control renaming the GameObject and Materials during export.

The FBX Exporter ensures compatible naming with Autodesk® Maya® and Autodesk® Maya LT™ to avoid unexpected name changes between Unity and Autodesk® Maya® and Autodesk® Maya LT™. During export the FBX Exporter replaces characters in Unity names as follows:
- Replaces invalid characters with underscores ("_"). Invalid characters are all non-alphanumeric characters, except for the colon (":").
- Adds an underscore ("_") to names that begin with a number.
- Replaces diacritics. For example, replaces "é" with “e”.

NOTE: If you have a Material with a space in its name, the space is replaced with an underscore ("_"). This results in a new Material being created when it is imported. For example, the Material named "Default Material" is exported as "Default_Material" and is created as a new Material when it is imported. If you want the exported Material to match an existing Material in the scene, you must manually rename the Material before exporting.
Export Unrendered Enable this option to export meshes that either don't have a renderer component, or that have a disabled renderer component. For example, a simplified mesh used as a Mesh collider.
Preserve Import Settings Enable this option to preserve all import settings applied to an existing FBX file that is overwritten during the export.
If you export the GameObject as a new FBX file, the FBX Exporter does not carry over the import settings.
Don't ask me again Enable this option to use the same Export Options properties and hide this window when you export FBX files in the future.
If you need to reset this property: from the Unity Editor menu, select Edit > Project Settings > Fbx Export and enable Display Options Window.

Note: For FBX Model filenames, the FBX Exporter ensures that names do not contain invalid characters for the file system. The set of invalid characters might differ between file systems.

Default property values

If you set a Default Preset in the Preset Manager, the FBX Exporter automatically uses the values of this Preset as default property values. Otherwise, the FBX Exporter falls back to the values defined in Edit > Project Settings... > Fbx Export under FBX File Options.

However, if you modify the settings in the Export Options window during an export, the FBX Exporter preserves them as long as you keep the Unity session open.

Exporting with relevant system units

The FBX Exporter exports in centimeter units (cm) with the Mesh set to real world meter (m) scale. For example, if vertex[0] is at [1, 1, 1] m, it is converted to [100, 100, 100] cm.

In Autodesk® 3ds Max®, it is recommended to set the system units to centimeters to avoid any scaling on Model import and export.

There are no specific import options to adjust between Unity and Autodesk® Maya® and Autodesk® Maya LT™. When working in Autodesk® Maya® and Autodesk® Maya LT™, you can set the working units to meters if you prefer.

When working with large models in Autodesk® Maya® and Autodesk® Maya LT™, to ensure that the models clip to meters, adjust the scale of the near and far clipping planes for all cameras by 100x. In addition, you should scale lights and cameras by 100x so that objects display in the viewport.