I work from an outline and my current Work in Progress has the most detailed outline I have yet produced for a novel, 85 pages. I also work from an act structure. I used to be a three act sort of writer, Establishment, Conflict, Resolution because it tracked so easily onto western narratives but fairly recently I became a fan of the five act method. (Establishment, Rising Action, Point of No Return, Spiral out of Control, Resolution.) Between those two elements of pre-writing you might think that when it come time to put it all together the process would be fixed, and for some writers that is true, but my process still remains fluid.
My acts and my outlines do not put me on a set of narrow gage railroad tracks carrying inexorably towards a fixed destination. Rather they act like roadmaps, giving me the ability to peer ahead and navigate the terrain to reach my destination. Sometimes I even find that the basic structure as originally envision is in error.
Last night as I worked and neared completion of Act one for the new novel I stumbled across the realization that what I had conceived as the end of Act one simply had nothing to do with the actual organic structure of the act.
Act one started with the characters central story dilemma, the thing that is at the heart of is problem, and it ended with him taking command of the starship that will be the setting for the rest of the story. That taking of command is a very dramatic moment in the character’s life, representing an achievement that he has sacrificed much to achieve, and it has nothing to do with the story or plot structure. It would happen even if the character sat back and did nothing for the entire first act. His earning of the command has been laid out and paid for with the first book in this series.
What the character has been driving for and fighting for in the story so far is the obtain a particular mission for himself and his first command. A mission that he thinks will bring him a resolution to certain problems but in fact will only add to his physical and psychological dangers. It is when he gets the mission, when he thinks he has achieved a goal but instead has actually raised the stakes that the story transitions from Act 1, Establishment, to Act II, Rising Action.
You can spend weeks writing an outline, months thinking on structure, but when you actually start writing there are plenty of elements still to discover.