some questions about "portal "

   I am new in CEL and CS.
   When i use cel and cs, i met some questions.
    I have created two entities to describe the world and the Actor. "LevelEntity" is used to describe the world and "ActorEntity" is used to describe the actor.The questions is following:
   
   1. In  cel, it provides a property class -- "iPcPortal", I want to use this property class to get the portal's vertex  in world space, but i am not sure which entity i can add the "iPcPortal" property class to, ActorEntity or levelEntity? 
   2. In CS of "iPortal" interface, it provides a function of "virtual const csPlane3 &  GetObjectPlane ()=0 " , the description of it is "Get the object space plane of this portal", what does it mean of "object space plane "? Does it mean "object space"?
   3. I want to get the vertex coordinate in world space of a portal which is in the game world, but i don't know which function to use in "iPortal" to get the portal's vertex coordinate?
   4. In CS, the portal is rendering the contents of that other sector as seen through this portal, so if i want to get this content how can I do, or which function can i use to get it?  And Is the content which i get a picture or anything else?    

   Please help me!!!  Thank you!!

[res]

   2. In CS of "iPortal" interface, it provides a function of "virtual const csPlane3 &  GetObjectPlane ()=0 " , the description of it is "Get the object space plane of this portal", what does it mean of "object space plane "? Does it mean "object space"?

A portal is a polygon. The vertices of this polygon lie on a plane,  the portal plane. And yes, "object space" means that plane is in object space. (Portals have, like mesh objects, an object-to-world transform).

   3. I want to get the vertex coordinate in world space of a portal which is in the game world, but i don't know which function to use in "iPortal" to get the portal's vertex coordinate?

The is no "the" vertex coordinate, there are more than one vertex in a portal. iPortal has GetVertex*() and GetVertices*() methods you can use to access the vertices of a portal.

   4. In CS, the portal is rendering the contents of that other sector as seen through this portal, so if i want to get this content how can I do, or which function can i use to get it?  And Is the content which i get a picture or anything else?    

What do you mean? The contents of the portal are rendered to the screen.

If you want these contents on a texture or so you need to use some rendering to a texture.

-f.r.