In the video below we show some advanced CAD Snap functions that you may find helpful.
Most users know how to use the standard CAD Snaps like End Point, Mid Point, Near Line and Free Snap etc. However sometimes the snap you want is not actually on the line itself, it may be on a projection of the line from the start (backwards) or from the End (Forwards) to a point where the snap would be e.g. Perpendicular to the line - so you will often see projected snaps show up while you are drawing, however you move the cursor towards the snap point and they disappear on you. This video shows how to mitigate that problem and make good use of those extended snap functions, and explains why the disappear on you and how to avoid that from happening.
Hope this helps
Alan