I've decided to try this approach. When a new triangle is created I work our the average height of all 3 points, then i work out the height of the midpoint or center of the triangle, the difference between the midpoitn height and the average is the amount of error in that triangle. Now based on this difference and some calculation of the distance from the midpoint to the camera I can decide if I need to split the triangle.

I'm not sure what "calculation" to use for the error and camera distance to decide if I should split. Any ideas :?: