Physics Asset Box Extents reading in Meters instead of CM (Blender FBX Import Scale Issue)

UE 4.26

Hi everyone, I’m running into a frustrating scale mismatch between my Skeletal Mesh and my Physics Asset, and I’m hoping someone can point out what I’m missing in my Blender-to-UE pipeline.

My Setup:

  • I rigged a custom vehicle in Blender.

  • My units in Blender are set to Metric / 1.0 Unit Scale.

  • I applied all transforms before parenting the mesh to the bones (Both the Mesh and the Armature have a strict Scale of 1.0, 1.0, 1.0).

The Problem: When I import the FBX into Unreal Engine, the Skeletal Mesh looks perfectly fine. It sits in the world at the correct, realistic size.

However, when I open the Physics Asset, delete the default capsules, and create a new Box Collision around my vehicle_base bone, the scale is completely wrong.

  • For example, my vehicle is physically 3 meters wide.

  • In the Details panel for the Box shape, the Extent values show up as 3.0 instead of 300.0.

  • It seems the Physics Asset is reading the raw Blender meters instead of converting to Unreal’s native centimeters, which causes my vehicle to behave erratically (like flying or floating) when I simulate physics.

My Question: Why does the visual mesh scale perfectly, but the Physics Asset primitives are scaled down by 100? Is there a specific FBX Export setting in Blender (like Apply Scalings: FBX All) or an Import Setting in Unreal that I need to check to force the bones/physics bodies to recognize standard UE centimeters?

Thanks in advance for the help!