I don't know about extruding points. Once you have made a closed shape by adding edges, you can choose "Fill Holes" from the Edit menu, then extrude the resulting faces. You can use splines in a similar way, using "Fill" from the Build menu. Also, once you have your outline, you may want to use the Arc-Rotate to continue to add edges and faces to your model. Check out this page from the manual: http://www.anim8or.com/learn/manual/4_object_editor.html
I'm going to just keep on with the tube I made to initially start model. It worked out great initially, but now that I am at end of the tube, I needed to extrude top face, which isn't easy.
I'm relatively new to using anim8tor though I love it, as blender wont' work in Windows xp anymore, so anim8tor is a god send , really enjoying using it just takes a tad of getting used to given I can't extrude verts here.
My wip was a bit wonky as I didnt' realize ( due to modeling something from ref images can be challenging at times) a part of model ( not a huge deal, just annoying) had been incorrectly moved, so I had to delete those areas , then all was fine, then I selected leftover edges and filled and extruded that face as many times as I needed as I was working up the tree.
Worked fine.
I did find a very kewl youtube anim8tor video ( short clips of various features), where you make a spline , create a ngon circle near it, then choose extrude and use, I think it was, path option. THat creates a result similar to extruding text or such, and is perfect ( as a alternative way of doing limbs) way for doing trees I think, so I"ll prob. try that method out later.
TY for all info
cheers
nl