Ways to affect rock placements?

[Feferily]

I thought I saw somebody use a different way to change where the rocks spawn, using different terrain to change where they’ll pop up, but I can’t find it... is there a different method other than just covering everything on your island up except for those few plots for the rocks?

 

[SugarMage]

Is this what you're looking for?

 

[Feferily]

Is this what you're looking for?

Oh yes!! Easy to do too it seems! I was wondering if there was an easier way but it doesn’t seem too bad... thank you!