>>5830055Not him; try copying with exactitude a simple drawing, like a Bargue eye block-in, same-size, by measuring. There are many way to make small distance/angles; it's even more so when drawing from life.
>>5827747Same thing OP. There are two things you need to understand: 1- your eyes actually are very fine measuring tool, much more handy to use than any measuring tool 2- but as for any tool, you need to put it some time to train yourself to use it.
If you want to train your eyes, you can try copying drawings (distances, angles) with great accuracy, by using your eyes as much as possible, and only then using measuring tool to evaluate the quality of the measure. Eyeball adjustments until your feel satisfied, and check again. Do sight-size drawings at this stage;you can use tracing paper too at the end to evaluate proportions accuracy by yourself.
You can also train to reproduce angles, try to cut a line in 2/3/5, etc. Don't forget to also take the time to learn to use measuring tool properly.
Finally, to answer your question, I'm pretty sure most of them used their eyes to a great degree;some are known to have use mechanical help (e.g. Vermeer IIRC);you also have to keep in mind the technical limitations of the time (no artificial light, no photography, no Loomises, etc.)
