Here's a tutorial style post on how I made my crowd bases for Guilders. In the game the crowds are represented by a 3" round base. There's no rules as to how many miniatures should go on it, but I've made room for three.
When painting these I've drybrushed some different greys, picked out a few individual stones on each base and then added small bits of static grass.
Here's a guard totally unable to find that hiding thief!
Materials
Cardboard, XPS foam (1 or 2mm), paper, Green Stuff World pinroll and pva / wood glue.
Step 1Cut a 3" round circle and draw it onto the XPS foam. Cut those out with some scissors.
Step 2
For stability, I want to make inserts for the miniature bases. They're all based on 25mm bases, so draw three on it's large 3" base.
Step 3Cut out those 25mm inserts with a fresh hobby knife, needs to be really sharp. This leaves room in the middle of the crowd base for another miniature, if a player character enters and hides in the base.
Step 4
Glue. Lots of glue on the 3" bases, but on some thin cardboard and put pressure on it while drying. I placed a ton of books on top, we don't want them to warp too badly.
Bonus StepMess up some 25mm round bases with a knife (for better grip) and glue all those 1" discs to them. We don't want any waste!
Step 5Time to bring out the Green Stuff World roller. It'll keep the presured texture made in the XPS foam.
Mod Podge is amazing! It's some kind of varnish / glue thing. I've mixed some black into mine, so that it now dries a very dark grey. This will seal and harden the foam very well. I can't recommend this stuff enough for anyone working with foam.
After a nights work I have a bunch of finished crowd bases and a lot of 25mm bases for future miniatures.