How to capture rendered frames from an application and stream over network
I think you're confused on how rendering and animation work. 

A traditional model is nothing more than a bunch of triangles. So a model file coming from say Blender, etc. is just a list of vertices for the triangles. (with some added stuff if you want)

Rendering takes the scene definition and transforms a 3D scene (aka the models oriented somewhere in space) and creates a 2D picture.

Animation creates the illusion of movement by showing static pictures very fast (24 frames per second or more). 

Therefore, to have a spinning mug, your application would render each frame, then present them, at, say 30 fps.

Now, to stream the data, you can take two paths:


Render each frame on the server and stream them to the client with something like H.264
Stream the graphics commands to the client, and let them render them.


The first option is what something like OBS or Fraps and (maybe) Nvidia GameStream is doing. 
There's a paper that covers the 2nd option here