diff --git a/libs/gfx/include/psemek/gfx/armature.hpp b/libs/gfx/include/psemek/gfx/armature.hpp
index f869d03e..36338c35 100644
--- a/libs/gfx/include/psemek/gfx/armature.hpp
+++ b/libs/gfx/include/psemek/gfx/armature.hpp
@@ -79,6 +79,16 @@ namespace psemek::gfx
 		return bone_transform<T>{m1.rotation * m2.rotation, m1.scale * m2.scale, m1.translation + m1.scale * geom::rotate(m1.rotation, m2.translation)};
 	}
 
+	template <typename T>
+	bone_transform<T> inverse(bone_transform<T> const & m)
+	{
+		// [(1, T) * (S, 0) * (R, 0)]^-1 = (R^-1, 0) * (S^-1, 0) * (1, -T) =
+		// = (1, - R^-1 S^-1 T) * (S^-1, 0) * (R^-1, 0)
+
+		auto ir = geom::inverse(m.rotation);
+		return bone_transform<T>{ir, T{1} / m.scale, - geom::rotate(ir, m.translation) / m.scale};
+	}
+
 	template <typename T>
 	bone_transform<T> lerp(bone_transform<T> const & m1, bone_transform<T> const & m2, T t)
 	{