Lock the add function so that it creates a object on the surface of another mesh.

basically I’m trying to find a way to extrude a singe vertice without it heading above or below the mesh I’m working on.

for example, say you’re making a remote, and you want to start on the buttons,
is there a way to create a vertice directly on the surface of the mesh?

You could make a selection of verticies and then using Ctrl-S and snapping the cursor to selection will allow the next object to either be created there or to be moved there accurately. Create your vertex, make sure it is selected and then use Ctrl-S and snap selection to cursor from there. It will be in the center of the cursor. Without a picture, I’m shooting in the dark here about what you are trying to achieve.

Retopo.

Enter edit mode and the option wil apear. Only works in “shaded mode”.