Exigence is basically a problem that persuades writers to write to the audience. When I think of exigence I sometimes think of purpose because both are reasons why you write however with purpose, you are focused more on the intended outcome of your writing not the problems that lead to the writing. (Exigence)

Simply put the exigence would not be my professor giving us an assignment to do but rather what motivates us to write about whatever topic we decide upon. For example with my Technical Description I described a 3D printer because it is an item I actually enjoyed using the first few times I used one and because its something most mechanical engineers will need to use frequently.