From the Unity 3D manual on importing meshes from 3D modeling software: Unity’s physics system expects 1 meter in the game world to be 1 unit in the imported file. If you prefer to model at a different scale then you can compensate for it here. defaults for different 3D packages are as follows
- .fbx, .max, .jas, .c4d = 0.01
- .3ds = 0.1
- .mb, .ma, .lxo, .dxf, .blend, .dae = 1