X-Muscle System is an add-on for creating physics-based tissue simulations and muscular systems. It provides tools to visualize realistic skin surface deformations that respect the volume preservation of body muscles, fat, and skeletal bones. Users can generate flexor and extensor muscle types, apply muscle pinning, and use bendy muscles that follow the bone chains of character rigs.

The tool integrates with native Blender features like Shape Keys and the Mirror modifier. It includes functions like auto-weight painting, automatic bone attachment, micro skin controllers, and an X-Mirror option for symmetrical workflows. The add-on is compatible with various armature types and custom rigs, including Rigify, Auto-Rig Pro, and BlenRig5. Additionally, the package includes an Anatomy Bundle featuring rigged skeleton models for humans, horses, cats, dogs, and carnivorous dinosaurs.