diff --git a/__init__.py b/__init__.py
index 5774c5c..122398e 100644
--- a/__init__.py
+++ b/__init__.py
@@ -105,6 +105,20 @@ def _floatp(x):
     assert x.typecode == 'f'
     return x.buffer_info()[0]
 
+vec3_rotate = _lib.rk_vec3_rotate
+vec3_rotate.argtypes = (
+    _vec3p, # ret
+    _vec3p, # vec3
+    _vec3p, # axis
+    ctypes.c_float) # angle
+
+
+vec3_mul_vec3 = _lib.rk_vec3_mul_vec3
+vec3_mul_vec3.argtypes = (
+    _vec3p, # ret
+    _vec3p, # a
+    _vec3p) # b
+
 mat3_rotation = _lib.rk_mat3_rotation
 mat3_rotation.argtypes = (
     _mat3p, # ret
diff --git a/cpp/math.cpp b/cpp/math.cpp
index ee2da7b..192941b 100644
--- a/cpp/math.cpp
+++ b/cpp/math.cpp
@@ -15,6 +15,21 @@
 
 #include "math.hpp"
 
+void rk_vec3_rotate(
+    rk_vec3 & ret,
+    rk_vec3 const & vec3,
+    rk_vec3 const & axis,
+    float const angle) {
+    ret = glm::angleAxis(angle, axis) * vec3;
+}
+
+void rk_vec3_mul_vec3(
+    rk_vec3 & ret,
+    rk_vec3 const & a,
+    rk_vec3 const & b) {
+    ret = a * b;
+}
+
 void rk_mat3_rotation(
     rk_mat3 & ret,
     rk_vec3 const & axis,
diff --git a/cpp/math.hpp b/cpp/math.hpp
index 7abed16..2bd03ac 100644
--- a/cpp/math.hpp
+++ b/cpp/math.hpp
@@ -26,6 +26,17 @@ typedef glm::vec4 rk_vec4;
 typedef glm::mat3 rk_mat3;
 typedef glm::mat4 rk_mat4;
 
+RK_EXPORT void rk_vec3_rotate(
+    rk_vec3 & ret,
+    rk_vec3 const & vec3,
+    rk_vec3 const & axis,
+    float const angle);
+
+RK_EXPORT void rk_vec3_mul_vec3(
+    rk_vec3 & ret,
+    rk_vec3 const & a,
+    rk_vec3 const & b);
+
 RK_EXPORT void rk_mat3_rotation(
     rk_mat3 & ret,
     rk_vec3 const & axis,