This time I'm going over the half tabard I sculpted. While it wasn't part of the original commission, I offered to add it because I think it adds character and helps with making the model a little more dynamic looking.
I've been using this technique for a couple years now and it's real similar to the one recently posted on DakkaDakka (that won the tutorial competition!) If you're willing to put the time and effort into it, I think it creates a great result. Keep in mind though, it does take some work.
As a side note, at the request of my client, I added a small Chaos element under his left foot to make him a little more imposing and change his stance ever so slightly.
Back to the tabard.
First step is to cut a piece of posterboard in the general shape of the tabard. It doesn't have to be exact, just close enough. Superglue it in place and then... superglue the whole piece. Yep, let the superglue soak into the posterboard and dry. This basically turns the posterboard into a plasticard. I suppose you could do the thing with plasticard but the posterboard is easier to cut and use for me and it doesn't add any depth either like plasticard might do.
Second step is the greenstuff. Take a blob, enough to cover the whole piece of posterboard with a layer a few milimeters think. The thicker the layer of greenstuff, the deeper the folds you can create. Figure out where you want your folds to be and it's just a matter of working them into the greenstuff. This is the hardest part, you want to make sure you get a smooth finish and a natural look.
And here's the finished tabard. Since I planned on adding scrolls and Terminator honors, I left the upper portion of the tabard (where it meets the belt) a little undefined near his right leg.
Project Link: Codex Space Marine Librarian conversion