I assume the ‘ Drawing Assistant’ is just what produces the endpoint and similar markers when working round a drawn object?
The LogiCursor allows you to align the cursor with an existing entity, for precise placement. Unlike snaps, which distinguish point on a surface, the LogiCursor displays intersections along an axis, tangent, perpendicular, 45-degree angle., parallel, and co-planar and cylindrical faces.
Drawing the countersunk hole then seems to involve guessing which face has which face number. Is there a way of knowing before drawing the hole?
When you click on a face the edges will highlight, if more than one face is under the cursor then an ambiguity popup will give you some choices to pick from, wire frame mode will show the selection better. As you get more experience doing this shade mode will work for you in most cases.
There is also a yes/no choice ‘Project from referenced snap along hole/boss axis’ which I don’t understand.
What this is telling you is the "LogiCursor" (old name was "Drawing Assistant") has snapped to a curve that is not on the selected surface. Saying yes the program will use the snap as the center point for the hole along the current axis, saying no will ignore the snap. In isometric view, you can easily snap to a hidden edge or other snap point that is on the workplane, the LogiCursor defaults to the workplane until it intercepts some other object that is off the workplane.
" to fix that, after creating the hole, select "Wire Frame" mode and using the "Select Deep" tool with the "Gripper" enabled, draw a fence around the hole and countersink and then move it to the correct location.”.
This only works with the "Gripper". Drag a fence around the hole and counterbore or countersink if any and move it using the gripper controls, holding the "Option" key will drag out a new hole and allow it to be placed as needed.