It's not possible using just the in game commands, you would need an external program. You might take a look at the Guide to Random Phrases! thread and see if that could be adapted to your purpose.
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If all else fails, you can set a keybind to activate a power, do the costume change, then load a new keybind that just switches which costume it changes to. It'll be a set order rather than random, though.
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Hey all
I've got a concept for a shapeshifting character and I'd like to be able to change his costume whenever I use Build Up. I know I can create a bind to change to a specific costume but I'd like to have a random costume slot be chosen. Anyone know if this is possible and, if so, how to do it?
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