Importing Content into Unreal Engine from Maya

FBX 

.fbx

The recommended format for geometry, animations, and skeletal meshes.

OBJ

.obj

Works best for static geometry but doesn’t handle animations.

Universal Scene Description (USD)

.usd

Useful for large complex scenes and for collaboration with teams. Requires the USD Importer plugin to be enabled. For more information on using them, see Universal Scene Description.

FBX

.fbx

The recommended format for geometry, animations, and skeletal meshes.

OBJ

.obj

Works best for static geometry but doesn’t handle animations.

Alembic

.abc

Works for complex animation caches, hair, cloth, or vertex animations. Requires the Alembic Groom Importer plugin to be enabled. For more information, see Alembic File Importer.

Universal Scene Description (USD)

.usd

Useful for large complex scenes and for collaboration with teams. Requires the USD Importer plugin to be enabled. For more information on using them, see Universal Scene Description.

PNG

.png

This is a lossless format that preserves transparency that can be highly compressed. This is used for textured surfaces and for channel packing with grayscale different image data stored in RGB channels. 

Targa

.tga

This is a lossless format that preserves transparency while avoiding potential issues of PNG. It is uncompressed, which can also speed up loading and editing. 

JPG

.jpg and .jpeg

This is a lossy format that can be highly compressed. Because of this, it should not be used when creating your source assets. 

Photoshop

.psd

This is a lossless, uncompressed format that retains the source files layers and data. 

Cubemap

.dds

These are compressed or uncompressed files that contain multiple images with various layouts in 2D layouts, 3D volume textures, and cubemaps. These are most commonly used for skyboxes and distance backgrounds.

HDR Image

.exr

This is a high dynamic range (HDR) image format that preserves more color data and brightness variations than other formats like PNG and JPG. This makes it ideal for using these with sky spheres and sky lights.

Illuminating Engineering Society Light Source Profile

.ies

These are defined profiles of lights that describe their distribution from a light source using real-world measured data. For more information on using them, see IES Light Profiles.

• Unreal Engine uses Centimeters as its default unit of measurement.

• Unreal Engine’s coordinate system is left-handed and uses a Z-up axis

  • The X-axis is Red and faces forward.

  • The Y-axis is Green and faces right.

  • The Z-axis is Blue and faces upwards

• For more information on Unreal Engine’s coordinate system, see Coordinate System and Spaces.

• Materials

  • Maya’s materials must be rebuilt with Unreal Engine’s material system.

  • You can include media, such as textures, with an exported file that can be optionally imported and create a basic material to apply to geometry with diffuse maps, normal maps, and so on mapping to ones in Unreal Engine.

• Textures

  • It’s recommended to create and import your textures separately into Unreal Engine.

  • For source files, choose a lossless format to preserve quality during development. For instance, consider the differences of using PNG, TGA, or JPG for textures as an output versus development resource.

  • For texture compression, know that the engine handles compression automatically. However, you can customize compression settings for individual textures using the Texture Asset Editor.

  • For alpha channels, consider how you work with transparency for a material in Unreal Engine and what type of image format you choose. For instance, TGA may handle alpha channels better than PNG in some cases.

  • Consider disk space versus memory usage. Disk space is less critical than memory usage (VRAM) for performance. The engine compresses textures to optimize memory usage.

• UVs

  • Ensure all UVs for geometry are laid out in such a way that makes them ideal for applying textures and materials to them. For example, modular geometry may rely heavily on tiled textures and materials whereby you’d overlay the UVs to get higher texel density with a lower resolution texture. For things like characters or unique geometry, you’d want to have unique UVs for most things with no overlapping.

    • If your project is using precomputed (“baked”) lighting, geometry should have no overlapping UVs, otherwise you’ll have visible artifacts on the mesh. To learn more about lightmapping and their UV layouts, see Understanding Lightmapping in Unreal Engine.

  • UDIM workflows are supported with Virtual Texturing features. To learn more about UDIM support in the engine, see Virtual Texturing.

• Skinned Meshes

  • Ensure bones and joints are properly skinned and named clearly. Unreal Engine imports skeletal structures for animation.

  • Clean Skeleton with one root and no scaling on joints.

• Animations

  • Export animations separately or bundled together in the same FBX file.

  • Blend Shapes (Morph Targets) should be exported with Deformed Models checked to include this morph data.

  • Unreal Engine uses root motion, make sure your rig and animation support this, if needed.

• Export Clean Up Practices

  • Center an object’s pivot point to the world origin (0,0,0) on export from Maya. Unreal Engine uses this as the pivot point location on the mesh during import. Geometry offset from the world origin will have an offset pivot point from its geometry. This can make working with assets in Unreal Engine more difficult.

  • Freeze transformations and delete history.

  • Ensure proper naming conventions for meshes, joints, and materials.

  • Remove unused nodes or hidden objects.

• Level of Detail (LODs)

  • You can manually set up LODs for geometry in Maya, but there are auto-generation tools you can use for static and skeletal meshes in Unreal Engine to do this for you. 

• Nanite

  • Nanite supports high polygon meshes without requiring decimation. It supports both static and skeletal meshes.

    • For more information on using Nanite with meshes, see Nanite Virtualized Geometry.