Hammer Units to Centimeters: Converting Source Engine Scales to Metric
Understand the exact mathematical conversion between Valve’s Hammer Units (HU) and standard metric centimeters across Blender, Unreal Engine, and Maya.
When designing level environments in modern 3D software for Source Engine or converting legacy maps to Unreal Engine, scale mismatches frequently cause character movement and doorway clearance issues.
1. The Standard Scale Standard: 1 Hammer Unit in Centimeters
By default in Valve’s Source Engine, 1 Hammer Unit equals 0.75 inches (1.905 cm). Standard player characters stand 72 Hammer Units tall (approx. 137 cm or 180 cm depending on collision bounds), making door heights standard at 128 units (243.8 cm).
2. Configuring Blender Grid snapping to Hammer Units
To model assets in Blender for Source Engine, set Unit Scale to 0.01905 in Scene Properties. This aligns Blender’s grid snapping directly with 16, 32, and 64 Hammer Unit increments.
3. Converting Source Engine Maps to Unreal Engine Metric Units
Unreal Engine operates natively on a strict 1 Unit = 1 Centimeter metric standard. When re-creating Source maps in UE5, multiply Hammer Unit measurements by 1.905 to achieve accurate real-world scale proportions.