I would have to say the moderators on CGtalk have to be some of the best in the business which is fitting considering the level talent and dedication that exists here.
This is a wonderful challenge on a number of levels. Very difficult however. (at least for me, everyone else makes it look easy.)
Lots of great photos out there on the net to choose from, I settled on these two:
They both contained interesting shapes and relatively easy lighting. I was also interested in the humans that appear in the images, a nice handy reference for getting sizes right I hope.
I brushed out the figures and extended the canyon floor. I've merged the images, I wanted the feeling of a narrow canyon in which a colony could easily hide / protect itself. What research there is to do in the middle of the desert is somewhat beyond me.
Here is the final(?) plate.
I am happy with the look but there some issues at the moment with the addition, please don't be shocked if I move things around a bit between now and the final. I hope everyone is having as much fun as I am with this. I am humbled by you all.