Smarter modeling

Hi, am pretty new to Blender but have worked with many cad/cam systems. I have used programs that have a group command, that is to say that if you have an object, all the faces, vertices and edges can be grouped for faster modeling.
A perfect example is a JCB model I downloaded, the artist is highly skilled and it is a perfect model, however when I started to move the model I noticed the computer slowing down. I selected one of the tyres and went into edit mode, the artist made the tyres out of a torus and there is a huge amount of information in each tyre, is there a simple way to join all the entities? using face gen would take too much time.
Another example is our friendly cube that Blender starts with, if I select one face and subdivide it the joining faces are also divided. Is there any way to stop this?
Any help would be great.

I’m not sure what exactly you mean but it sounds to me that you are expecting n-gons which blender currently does not support.
Blender is able to show you f-gons on imported meshes but theser are just fakes.
Blender can handle quads and tris so in order to subdivide a face on that cube the other faces have to be converted into three tris.
There is currently a refactoring going on called BMesh that is capable of handling ngons but it will take quite some time until all the tools are ported so I can’t really say when this code will make it into a official release.

Go into EDIT mode and select the face of your cube which you want to be “different”. Push P-key to separate it as a different mesh. Now will subdivide without running into the other face.
In object mode you can use CTRL-J to “join” selected objects, this does not actually add faces.

What you are calling “a group command” sounds to me like linked duplicates in Blender . Linked duplicates share the mesh data, but are a separate instance of that same data . So in your tire example there can be one detailed tire and the other three could be linked duplicates to save on resources . You create a linked duplicate with Alt-D .

And while Lancer’s workaround “works”, the fact is that in Blender’s mesh data structure, even after you add the subdivided plane back into the original cube, the subdivided plane is still not properly connected to the rest of the cube … Like musk mentioned you need N-gon (or f-gon) support to do this “legally”, which Blender currently does not have, but which like musk said is being worked on …

If you are coming from a CAD/CAM background you are most likely very used to using parametric objects (which Blender does not support) to get your shapes (Blender’s booleans are mesh based and usually create a mess), or a full set of NURBS tools (which Blender is very wanting in) to play with, but Blender isn’t/wasn’t designed for technical work . It is an artist tool and has a full set of mesh modeling tools . The only way to get “smarter modeling” is to gain experience with mesh modeling which is closer to drawing or sculpting then machining a part or laying out a house …

Thanks for taking the time to reply folks, you have cleared up a lot.