The FBX export is the single most common failure point for Blender artists targeting Unreal Engine 5. You finish modeling, hit export, drag the file into UE5 — and the mesh appears at 100x the intended size with broken smoothing groups. This guide covers every critical FBX export setting so your assets import correctly the first time.
Why Blender and UE5 Disagree on Scale
Blender works in meters by default with a unit scale of 1.0, while Unreal Engine uses centimeters. This means 1 Blender unit = 1 meter, but UE5 interprets the same value as 1 centimeter — resulting in assets that appear 100x too large on import.
The fix is in the FBX export dialog under Transform → Scale. Set it to `0.01` to compensate for the unit difference. Alternatively, apply your scale before export with `Ctrl+A → Scale` and export at scale `1.0`. Most artists prefer the apply-scale approach since it keeps FBX values clean and avoids downstream confusion.
There's also the Apply Scalings dropdown in the export panel. Set it to FBX Units Scale — this bakes the scale directly into the FBX's units rather than applying a transform multiplier, which UE5 handles more reliably.
A common gotcha: if you parent objects and apply scale only on the parent, child objects inherit the old transform. Always select all objects with `A`, then apply scale globally.
Essential FBX Export Settings Panel by Panel
Open the FBX exporter: File → Export → FBX (.fbx). Here are the critical settings:
Include:
- Selected Objects: ON (export only what you need)
- Object Types: Mesh + Armature for skeletal assets; just Mesh for statics
Transform:
- Scale: `1.0` (if scale applied) or `0.01` (if not)
- Apply Scalings: `FBX Units Scale`
- Forward: `-Y Forward`
- Up: `Z Up`
- Apply Unit: ON
- Use Space Transform: ON
Geometry:
- Smoothing: `Normals Only` to bake Blender's Auto Smooth as split normals — what you see in Blender is exactly what UE5 gets
- Tangent Space: ON if your normal maps use Blender-baked tangents; OFF if rebaking in Substance Painter
Armature:
- Primary Bone Axis: `Y Axis`
- Secondary Bone Axis: `X Axis`
- Only Deform Bones: ON — strips IK targets, pole vectors, and control bones that shouldn't exist in-engine
- Add Leaf Bones: OFF — UE5 doesn't need them and they bloat the skeleton hierarchy
Here's a Python export snippet for automating static mesh FBX export from the Blender CLI:
```python
import bpy
bpy.ops.export_scene.fbx(
filepath="/path/to/output/my_asset.fbx",
use_selection=True,
object_types={'MESH'},
global_scale=1.0,
apply_unit_scale=True,
apply_scale_options='FBX_SCALE_UNITS',
bake_space_transform=True,
axis_forward='-Y',
axis_up='Z',
mesh_smooth_type='NORMALS_ONLY',
add_leaf_bones=False,
)
```
Run it with: `blender --background my_scene.blend --python export_fbx.py`
Exporting Skeletal Meshes and Armatures for UE5
Skeletal mesh exports have additional requirements on top of the static settings above.
Prepare the armature first. In Pose Mode, select all bones (`A`) and verify the rest pose is clean. Confirm the armature has a root bone at the world origin — UE5 expects this and will create one automatically if missing, which can offset animation playback.
NLA and baked animations. If your animations use the NLA editor, bake them before export: Object → Animation → Bake Action with Visual Keying and Clear Constraints ON. In the FBX export panel, enable Bake Animation, set your start and end frame range, and enable All Actions to export every NLA strip as a separate animation take. UE5 imports each take as a separate Animation Sequence.
Splitting skeleton from mesh. For complex characters, export the skeleton and all meshes (body, armor, hair) in separate FBX files using Only Deform Bones. UE5's import dialog lets you assign any mesh to an existing skeleton — far cleaner than re-importing the skeleton every time you update a mesh or LOD level.
Smoothing Groups and Hard Edges Before Export
UE5's FBX importer reads smoothing groups to reconstruct normals. The most predictable workflow: mark sharp edges in Blender with `Ctrl+E → Mark Sharp`, enable Auto Smooth in mesh properties, then export with Smoothing: Normals Only. UE5 receives your exact split normal data without recalculating anything.
One critical check before export: use Overlay → Face Orientation to verify no inverted faces (shown in red). UE5's default material is single-sided, so flipped normals create invisible holes in your mesh that are frustrating to track down after the fact.
When none of the export fixes resolve shading issues, UE5's Import Normals dropdown in the FBX import dialog is your escape hatch — cycle through Import Normals, Import Normals and Tangents, and Compute Normals until the shading looks correct.
FBX vs GLB for UE5 — Which Should You Use?
| Criterion | FBX | GLB / GLTF |
|---|---|---|
| UE5 native support | Full (Skeletal + Static) | Full (UE5.0+, Nanite-ready) |
| Skeletal mesh + animations | Best compatibility | Improving, some edge cases |
| File size | Larger (XML-based binary) | Compact |
| Third-party tool support | Universal | Growing fast |
| Open standard | Autodesk proprietary | Khronos open standard |
Verdict: Use FBX for skeletal meshes with animations — it remains the most battle-tested format across the full toolchain. Use GLB for static meshes, environment props, and anything destined for the web or multi-engine pipelines.
Many assets on BitSoul's marketplace are available in both formats. GLB is the better pick for static environment packs; FBX remains the default for rigged characters.
Quick Export Error Reference
| Error in UE5 | Likely Cause | Fix |
|---|---|---|
| Mesh is 100x too large | Scale not applied | Apply scale or set export scale to 0.01 |
| Shading glitches / seams | Wrong smoothing export | Export with Normals Only + Mark Sharp |
| Missing bones | Control bones exported | Enable Only Deform Bones |
| Animation plays backwards | Wrong axis setting | Forward: -Y, Up: Z |
| Invisible mesh faces | Flipped normals | Recalculate normals with Shift+N |
| Root bone offset | No world-origin root | Add root bone at 0,0,0 in Blender |
Getting FBX export settings right is a one-time investment. Save your export settings as a Blender operator preset so you never have to reconfigure them on a new project. For verified game-ready static and skeletal assets in correct FBX format, browse BitSoul's marketplace — every asset is import-tested in UE5.