This is a WWII British Challenger 17-pounder gun tank in 1:100 scale that I 3d printed from a design by the estimable Mr. Bergman, and
posted a WiP for on my blog recently.
I tried a new (to me) three-layer method of painting mud and filth, with which I'm fairly happy. I first painted a couple of layers of loose, sloppy, thinned blotches of VMC
Earth all over the running gear, and on the hull where I wanted mud splashes, before washing the whole model with Citadel
Agrax Earthshade. Then, over the top of that, I sponged speckles of VMC
German Camo Beige. I also sponged it, very very lightly, on other places on the hull and turret, just to add a suggestion of dirt and to add a bit of visual variation to the panels.