I restore wooden boats for a living. The technics and tools we use have not changed much the last view hundred years and some of the tools and technics go al the way back to the beginning of boatbuilding. One of the most important tools in boatbuilding, one that has been used for thousands of years, are our eyes. We off course use our eyes for most jobs we do but in boatbuilding we used them not only for seeing the quality of our work, we use them also to see the lines and shape of the planks we use for the hull or the masts. Boatbuilding is not an exact science where you can put measurements on a piece of wood and cut it out. A lot of lines on a boat are not straight end even if you manage to lay out a nice plan and line up everything nice and straight, time and humidity will warp the wood and ruin your careful laid out plan. If I make a plank to wrap around the ribs I can make some measurements but the final line, a line that is often a few meters long with a slid curve, will be made with my eyes. And like in real life I have to walk around the problem/plank, lower my head for another perspective, till I have seen it from all sides and adjust the solution/line till it looks right.