Class with general and specialized attributes

How to model a class with general and specific attributes based on type. For example I have a Primitive class. The Primitive class has the following general members : PrimitiveType, translation, rotation, plus additional fields based on the primitive type.

enum PrimitiveType
{
   CYLYNDER,
   CUBE,
   CONE
}
class Primitive
{
   string name;
   PrimitiveType type;
   double positionX,positionY,positionZ;
   double rotationX,rotationY,rotationZ;

  // following members are if primitivetype is CYLYNDER
   double height;
   double radius;

  //following members are if primitive is CUBE
  double height;
  double width;
  double length;

};

I can of course do inheritance and make Primitive and Cylynder and Cube classes that inherit from Primitive. But classes have not polymorphic relationships between themselves, so I do not to use inheritance. I need them as just plain structures that hold attributes.

I can make also composition and make Cylynder and Cube classes that have Primitive member. But I need to store objects of Cylynder,Cube and Cone in one vector. So if I do composition how I will store them in one std::vector .

I basically need to model the structures in a such way that I need to met the following requirements :

1) store objects of the different types of components in one std::vector

2) store object of different types in a easy readable and editable config file. In the config file I want to save only the specialized attributes that are relevant for the specific type of the primitive, and not the specialized attributes for all primitive types. So I want to get something like this in the config file :

<Primitive>
 <name>Primitive1</name>
 <type>CYLYNDER</type>
 <positionx>0</positionx>
 <!-- other common attributes here, omitted to save space -->

 <!-- specific primitive type attributes -->
 <height> 10 </height>
 <redius>5</radius>
</Primitive>
<Primitive>
  <name> Primitive2 </name>
  <type> CUBE </type>
  <positionx>0</positionx>
  <!-- other common attributes here, omitted to save space -->

  <!-- specific primitive type attributes -->
  <height>10</height>
  <width>10</width>
  <length>10</length>
</Primitive>