For what is worth:
I am definitely a "newbie" but experimented with using textured ceiling paint to cover carved styrofoam as an alternative to Hydrocal or joint compound. I applied both by putty knife and also soaked paper towels. Created a nice realistic textured finish ready for final finishing. Texture paint comes in various forms: popcorn, sand, etc. I would think one could also use on flat ground surfaces and could be easily colored by additives.
Any down sides I should be aware of?
Welcome aboard!
This topic has been brought up before, with some people swearing by texture paint and some swearing at it. Seems to me that, if it achieves the results you want, go for it.
I, personally, had some less than wonderful results with texture paint, but that might have been the specific product (or even the specific can.) Since one sample does NOT make a statistical universe, I won't say that it won't work. I will say that I have no plans to use it in my own modeling.
Just my . Feel free to disagree.
Chuck (modeling Central Japan in September, 1964)
I've used textured ceiling paint to cover a foam base for many years. I guess I'm one of those that swear by it. I use the sand finish so its relatively smooth. I've not tried using it for rock carvings, but it works create for smoothing transitions between foam layers.
The things I like about using it over foam is that it provides a something for the scenery to be glued to. Without it the glue will take DAYS to dry and then the ground will want to peel off the foam. Ceiling paint bonds well to the foam, takes paint well and absorbs the water/glue mix well. It is also somewhat flexible meaning that it is design to cover cracks on a ceiling and not crack itself. It is not as brittle as hydrocal or joint compound. A definite plus when used over foam.
jktrains