Have you investigated the following:
Urinary infection
Not drinking enough=not stretching the bladder sufficiently to give a good need to wee signal
Constipation can indirectly cause wetting
Afraid to use pre-school loos for some reason
Embarrassed to ask pre school staff to go to the loo
Refusal to comply when you remind, out of defiance
Same, but because she simply doesn't care about being wet
Physical problem with her bladder/urethra/ kidneys
Can you trace this wetting back to something that happened 9mths ago, illness, bereavement, house move, divorce or separation, new baby, etc anything at all that could have started this behaviour.
I would take dd to the Dr to rule out any of the physical causes, then formulate a plan of action including dd. Explain that she was dry once, why not now? Ask how she would like to go to the loo, would she prefer to use a potty instead for now? I know it seems like a backward step, but if she uses it and stays dry that's progress, surely? Do the pre-school staff have any ideas, and will they stick to your plan when dd is there? If she hates the loos there, could she have one of her own loo reducer seats to use there? (A friends dd did this in reception class, but gave it up after a term of her own accord)
I think that at her age, she would be able to understand the consequences of wetting or not, if it's just laziness. If she wees in the right place she gets a treat, if she wets she will have to stop what she's doing, change her pants, clean the area she has wet, and wash the wet clothes by hand. And I bet it won't take long for her to realise that it will be easier and quicker in the long run to just go to the loo.