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Tags: fbx, gltf, obj, usdz, import, export, scaling, game-dev Last updated: 2026-06-27

Asset Import / Export Formats Cheatsheet

Quick Reference

Format	Best For	Avoid For
FBX	Animation, skeletons, scene export	Web, open-source pipelines
GLTF/GLB	Web, real-time, PBR materials	Complex rigging (limited)
OBJ	Static meshes, quick exchange	Animation, materials
USDZ	AR/VR, Apple ecosystem	Game engines (limited support)

FBX (.fbx)

When to Use

Exporting rigged characters with skeletons and skinning.
Complex animation clips (multiple takes).
Scene hierarchies with transforms.
Interchange between Maya, 3ds Max, Blender, MotionBuilder.

Import Settings (Unity)

Setting	Recommended
Scale Factor	1 (or 100 for cm→m conversion)
Mesh Compression	Off for skinned meshes
Read/Write Enabled	Only if modifying mesh at runtime
Animation Type	Humanoid (for Mecanim), Generic (for non-human)
Avatar Definition	Create From This Model

Import Settings (Unreal)

Setting	Recommended
Import Uniform Scale	1.0
Import Materials	On (creates material instances)
Import Textures	On (extracts embedded textures)
Skeleton	Select existing if reusing rig
Animation Length	Exported Time or Animated Time

Common Pitfalls

Scaling — 1 Blender unit = 1m in Unity/Unreal. Export with scale 1.0 and Apply Scalings: FBX Units Scale.
Axis — FBX is Y-up; Blender is Z-up. Enable !Experimental: Apply Transform on export.
Bone orientation — mismatched bone rolls cause twisted animation. Use consistent rest pose.

FBX Export (Blender)

Setting	Value
Scale	1.00
Apply Scalings	FBX Units Scale
Forward	-Z Forward
Up	Y Up
Apply Transform	On (experimental)
Bake Animation	On
NLA Strips / All Actions	All Actions

GLTF / GLB (.gltf / .glb)

When to Use

Web-based 3D (Three.js, Babylon.js, model-viewer).
PBR material workflows (metallic-roughness model).
Real-time engines with modern pipelines.
AR experiences (WebXR, 8th Wall).
Open-source projects (royalty-free standard).

GLTF vs GLB

.gltf — JSON + separate .bin (geometry) and textures. Human-readable, easier to edit manually.
.glb — Single binary file, all assets embedded. Preferred for distribution and web.

Material Model

GLTF 2.0 uses PBR Metallic-Roughness by default.
Extensions: KHR_materials_transmission (glass), KHR_materials_sheen (fabric), KHR_materials_clearcoat.
No custom shaders — stick to the standard material model.

Export Settings (Blender)

Setting	Value
Format	glTF Binary (.glb) for single file
UVs, Normals, Tangents	On
Vertex Colors	As needed
Materials	Export (PBR metallic-roughness)
Compression	On (Draco for geometry)
Animation	On (if animated)

OBJ (.obj + .mtl)

When to Use

Quick geometry exchange between any 3D tool.
Static props with no rigging or animation.
CAD-to-game intermediate format.
Texture baking workflows.

Limitations

No skeleton, no animation, no skinning data.
Materials limited to basic Kd/Ka/Ks/Ns in .mtl file.
No PBR support — only Blinn-Phong shading model.
One object per file (or multiple named groups).

OBJ Scaling

OBJ has no unit definition — tools assume different scales.
Blender exports OBJ at 1 BU = 1 unit.
Unity imports OBJ at 1 unit = 1m.
Solution: model to real-world scale; apply scale in engine import settings.

USDZ (.usdz)

When to Use

AR Quick Look on iOS (Safari AR).
Apple Reality Composer and RealityKit.
Apple Vision Pro spatial content.
Product visualisation with PBR materials.

When NOT to Use

Game engines (Unity/Unreal import is experimental).
Skeletal animation (limited USD support).
Non-Apple platforms.

Workflow

Export model as USD from Blender (.usdc preferred).
Use Apple’s usdzconvert or Reality Converter to package textures into .usdz.
Validate with usdzcheck tool.

Format Comparison Table

Feature	FBX	GLTF	OBJ	USDZ
Static mesh	Yes	Yes	Yes	Yes
Skeletons	Yes	Yes	No	Limited
Animation	Yes	Yes	No	Limited
PBR materials	Limited	Full	No	Full
Blend shapes	Yes	Yes	No	Yes
Binary embedded	FBX binary	GLB	No	Yes
Open standard	No	Yes	Yes	Yes
Web support	No	Yes	No	Safari only
File size	Medium	Small (w/ Draco)	Large	Medium

Scaling Reference

Source	Unit	Convert to Meters
Blender (default)	1 BU = 1 m	× 1
Maya (default)	1 unit = 1 cm	× 0.01
3ds Max (default)	1 unit = 1 inch	× 0.0254
ZBrush export	Varies (set on export)	Check export scale
CAD (STEP/IGES)	Usually 1 mm	× 0.001

Scaling Pitfalls

Symptom	Likely Cause	Fix
Model is 100× too large	cm→m mismatch	Set import scale to 0.01
Animations slide/skate	Root motion baked wrong	Re-export with Bake Animation + correct units
Skeleton collapsed	Hierarchy scale != 1	Apply scale to armature before export
Normal map inverted	Axis handedness mismatch	Flip green channel in normal map

Pipeline Quick Choice

Goal	Choose
Animated character to Unity/Unreal	FBX
Static prop to web viewer	GLB
Quick blockout between tools	OBJ
iOS AR demo	USDZ
Open-source game asset	GLTF
Skeletal mesh to Godot	GLTF (recommended over FBX)