They probably use the same model. 99.9% of all games made with daz3d will have the same models (charlotte/victoria etc.), if you're lucky they might have different morphs in a couple of games. Pateron backed devs, who work in their spare time don't have the time or resources to make orginal 3d characters from scratch, that would require a dedicated team of 3d modellers. We'd be lucky if we saw a update every 3 - 4 years
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You can make unique models like with alot of morphs and tweaks,
naughtyroad is a good example, his models looks like nobody else. But its faster and cheaper to buy some pro bundles from DAzshop and go from there. Think of models like actors, we see the same actors in many movies.