Realistic sand?

I wasn't sure which section to post this in exactly, but I have been wondering how realistic sand could be created. For example, in the game Uncharted 3, the sand underneath the character changes and moves as though real sand would. In real life a person can stand in sand and their feet will sink in slightly/make a footprints. I would really like to understand how something such as this could be achieved.

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It's just decals.

 

You can try using normal-mapped decals to create the footprints and to create the moving sand you can use some particle effects with a 'sand cloud'-texture on a particle system.

 

naughty dog FX artist. That worked by projecting a decal which modified the normals for the Gbuffer (at the time it wasn't a "gbuffer" as only recently did we move to real deferred rendering).

 

The tricks that artists/gfx programmers use to fool you!