Best medium for groundwork?

I have never heard of using anything like gthis for ground work. Personally, I use celluclay and I think some people might use plaster, but have not come across this stuff before.

I use the liquitex matte medium straight from the bottle and thinned also to glue down sand, rock, dirt, foliage, etc. to the prepared base. It is great stuff. I have used heavy gloss gel to make water and waves.

I should clarify that I build up the base contours with Celluclay, foam, whatever and use the matte medium to stick the groundwork down.

Thanks that helps alot!

i will build up areas with scrap wood but picked up a bunch of cork tiles i am going to try. plaster of paris works well for those areas where the vehicle DOESN'T sit. dries hard and fast but you can smooth it out with a sander. add rocks and maybe trees before it dries or you will be drilling holes. i have used liquidtex too mixed in cheap artist acrylics and actual dirt for my base ground cover.  for small bases i will use cheap modeling clay and slop paint it before adding ground cover. my next base, a ww2 wadi i will build up the wall elevation with wood. may use plaster of paris on the top but clay on the side of the wadi and the are where the vehicle sits so i can set my hydrocal rocks and press the vehicle into the terrain more easily.

Thinned Elmers tinted with craft acrylics is the brew I use to secure crushed kitty litter, sand, foam chunks, foliage, etc. The gel stuff you mentioned I use to make water or wet mud. Kitty litter makes the best rubble or rocky terrain. Just paint with craft acrylics. Dried parsley makes convincing leaves.