diff --git a/src/Shapes/Capsule.h b/src/Shapes/Capsule.h
index 2d85ddd97..fb0de064c 100644
--- a/src/Shapes/Capsule.h
+++ b/src/Shapes/Capsule.h
@@ -42,7 +42,7 @@ Unlike other elements the capsule doesn't support asymmetric scaling. When
 applying transformation, the scale factor is averaged from all axes. See
 @ref shapes for brief introduction.
 @see Capsule2D, Capsule3D
-@todo Assert for asymmetric scaling
+@todo Assert for asymmetric scaling to avoid costly sqrt?
 */
 template<UnsignedInt dimensions> class MAGNUM_SHAPES_EXPORT Capsule {
     public:
diff --git a/src/Shapes/Plane.h b/src/Shapes/Plane.h
index c3f3471d8..50058fc68 100644
--- a/src/Shapes/Plane.h
+++ b/src/Shapes/Plane.h
@@ -39,6 +39,7 @@ namespace Magnum { namespace Shapes {
 @brief Infinite plane, defined by position and normal (3D only)
 
 See @ref shapes for brief introduction.
+@todo Assert for uniform scaling to avoid costly normalization?
 */
 class MAGNUM_SHAPES_EXPORT Plane {
     public:
diff --git a/src/Shapes/Sphere.h b/src/Shapes/Sphere.h
index c100f90b3..dc4c5e2f0 100644
--- a/src/Shapes/Sphere.h
+++ b/src/Shapes/Sphere.h
@@ -42,7 +42,7 @@ Unlike other elements the sphere doesn't support asymmetric scaling. When
 applying transformation, the scale factor is averaged from all axes. See
 @ref shapes for brief introduction.
 @see Sphere2D, Sphere3D
-@todo Assert for asymmetric scaling
+@todo Assert for asymmetric scaling to avoid costly sqrt?
 */
 template<UnsignedInt dimensions> class MAGNUM_SHAPES_EXPORT Sphere {
     public: