diff --git a/Sources/Plasma/CoreLib/hsQuat.cpp b/Sources/Plasma/CoreLib/hsQuat.cpp
index da9c1667..4b8556b9 100644
--- a/Sources/Plasma/CoreLib/hsQuat.cpp
+++ b/Sources/Plasma/CoreLib/hsQuat.cpp
@@ -65,14 +65,14 @@ hsQuat::hsQuat(float rad, const hsVector3* axis)
     fZ = axis->fZ*s;
 }
 
-hsQuat hsQuat::Inverse()
+hsQuat hsQuat::Inverse() const
 {
     hsQuat q2 = Conjugate();
     float msInv = 1.0f/q2.MagnitudeSquared();
     return (q2 * msInv);
 }
 
-hsPoint3 hsQuat::Rotate(const hsScalarTriple* v)
+hsPoint3 hsQuat::Rotate(const hsScalarTriple* v) const
 {
     hsQuat qInv = Inverse();
     hsQuat qVec(v->fX, v->fY, v->fZ, 0);
diff --git a/Sources/Plasma/CoreLib/hsQuat.h b/Sources/Plasma/CoreLib/hsQuat.h
index a61f484e..3153c194 100644
--- a/Sources/Plasma/CoreLib/hsQuat.h
+++ b/Sources/Plasma/CoreLib/hsQuat.h
@@ -71,7 +71,7 @@ public:
         { fX = X; fY = Y; fZ = Z; fW = W; }
     void GetAngleAxis(float *rad, hsVector3 *axis) const;
     void SetAngleAxis(const float rad, const hsVector3 &axis);
-    hsPoint3 Rotate(const hsScalarTriple* v);
+    hsPoint3 Rotate(const hsScalarTriple* v) const;
     
     // Access operators
     float& operator[](int i) { return (&fX)[i]; }     
@@ -94,7 +94,7 @@ public:
     float MagnitudeSquared();
     hsQuat Conjugate() const
         { return hsQuat(-fX,-fY,-fZ,fW); }
-    hsQuat Inverse();
+    hsQuat Inverse() const;
     // Binary operators
     hsQuat operator-(const hsQuat&) const;
     hsQuat operator+(const hsQuat&) const;