No rocks spawn with custom map options

Hello @13roken, welcome to the forums.

Are you sure you enabled the creation of Caves when you set up the World Options? It doesn't Add Caves by default as majority of DST players might not be able to run a server with caves on their PCs, so adding caves would be an intentional decision by the player if they are sure their PC is up to the task. So not clicking the Add Caves when you first generated the world, would be the only logical reason that I can think of as to why sinkholes don't exist in your world.

If you do not want to start over in a new world, I think there is a way to add them in a world save that didn't originally generate caves but you'll have to manually spawn in each individual sinkhole and ALSO be fiddling with the files and I think that'll be more time spent not playing.

To find where each individual position where sink holes are supposed to exist if caves was added, simply type the following command in the console(pressing tilde sign ~):

c_gonext'cave_entrance'

With regards to manually adding caves to an caves-deprived world, it'll take a while for me to write down the list of instructions for that, so I'd rather wait on whether you actually want to get caves the hard way, for your No Flint Challenge.

I still highly recommend you start over thought, it'll be much easier for you.

I hope I didn't misunderstand the situation, cheers.