FBX models distort in Godot mainly due to mismatched import settings (e.g., scale, axis orientation) or original model issues (non-uniform scaling, broken UVs).
Godot uses Y-up by default, so Z-up models (like from Blender) may rotate incorrectly. Wrong "Import Scale" values can stretch geometry. Non-uniform scaling in the original software (not applied before export) also causes distortion.
Fixes: Reset the FBX’s "Import Scale" to 1.0 in Godot’s import settings, or apply scale (Ctrl+A in Blender) before exporting the model.