That's kind of a problem to process. Crimson and Corruption act as a sort of switch. Having one messes a lot of stuff regarding the other. Breaking shadow orbs or crimson hearts count towards the same number and while they can distinguish the correct drops, in a corruption world breaking 3 crimson hearts will always spawn the eater of worlds no matter what and vice versa.
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W1K
GreyScale7287
sounds right, i was just hoping that could be done
Grumpy Squid
Here's a mod that will do that and more: https://forums.terraria.org/index.php?threads/terracustom-for-1-3.35346/
sharkman0101
You can use TerraCustom to generate a mock biome of the other Corruption in a world, but the world will still consider the orignal Corruption variant and will be treated as if it was that type of world.
GreyScale7287
oh cool, thanks.