There must be some specific activities (mental and physical) that take place when an architect commits himself to generate a concept.

Fundamentally, every concept is a risk taken by someone who is pursuing excellence. Therefore there has to be exploration and experimentation about a "fresh" idea. Quest for a fresh idea comes from acute observation of state of things. It also comes from a habit of seeing things in different light or changing the viewpoints.

Concept generation is a state of mind. It is an ongoing process. At any given point in time (with specific reference to a project) this process simply addresses issues specific to the project and then goes on. So, there is an accumulation of creative effort, every time enriching itself.

Visualization is another process that is integral to concept generation. Random visualization often is not as useful architecturally, as it is when connected to specific situation. It has to be in relation to spatial problem solving. Visualization has to be a mental activity firstly and then it can be represented and tested through models, renderings, write up and other media.