I’m making good progress with my improved terrain editing tools.  Right now I can right click to select the terrain and a goofy cone shows up.  The cone points down and shows the area that will be affected by clicking the mouse.  You can scroll the mouse wheel to move the cone up or down, changing the size of the circle within which vertices will be affected.  Right after I finished implementing all this I realized that a scaleable sphere centered on the mouse cursor makes so much more sense, so I’ll have to fix that.  In any case, if you have the magical cone up and click the left mouse button, any vertices within the circle of influence™ will move along the y-axis by 5 units.  You can then save the scene and the changes persist.  There are lots of things that need to be improved here but the basic functionality of being able to select a group of vertices with the mouse and change them with a click is totally working.  I honestly didn’t think I would get this far this fast, so hopefully I can polish this up a bit then make a real scene very soon.