Several of the controls used allow animated values. For example, the radius, and segments parameters may be animated. The developer uses a parameter block to store these values. The developer must define the parameter block descriptor which describes the properties of each parameter.

class  ParamBlockDescID {
 public:
  ParamType type;
  UserType *user;
  BOOLanimatable;
  DWORDid;
 };

This class is initialized by passing four values per parameter. These values are:

1. ParamType type - The Parameter Type - The following are the types which may be used:
2. • TYPE_INT - Integers values.
   • TYPE_FLOAT - Floating point values.
   • TYPE_POINT3 - Point values.
   • TYPE_RGBA - Color values - Red, Green, and Blue.
   • TYPE_BOOL - Boolean values.
3. TYPE_INT - Integers values.
4. TYPE_FLOAT - Floating point values.
5. TYPE_POINT3 - Point values.
6. TYPE_RGBA - Color values - Red, Green, and Blue.
7. TYPE_BOOL - Boolean values.
8. UserType* user - This value is NOT USED - it must always be passed as NULL.
9. BOOL animatable - This is a flag indicating if the parameter may be animated or not. Pass TRUE if the value may be animated and FALSE if just a constant value should be stored.
10. DWORD id - This is an ID assigned to each parameter. This is used for backwards compatibility if you change the parameter block structure in the future. There is a mechanism that allows older format parameter blocks to be converted to a newer format using these IDs to match corresponding parameters between the new and old format. This is described below under Backwards Compatibility.