What is this 'World Center' thing?

Valheim worlds are generated by sampling an infinite plain of Perlin Noise. You can think of this like an infinite world stretching in all directions. Valheim generates different "worlds" for different seeds not because the plain of noise changes, but because Valheim looks at a random point inside this infinite plain of noise. This is your "map center". The offset of where you're looking in that plain.

Despite the plain of noise being infinite the actual random offset is calculated by Valheim to always be within -10000,10000. That means many seeds have very similar offsets and thus very similar land masses. In fact so many seeds have the same center point that its possible to pick a center point and then very quickly try random seeds until you find a seed with that center.

To try this out, use the new random center pin dialog

First click here

Then click 'edit' to open the new dialog

At this point you need to know *where* you want the center of your world to be. If you have a world open you can select "click on map" to just recenter your map on a different set of islands. Or you can consult this atlas. Click the image to see a version with a grid!

The atlas contains all possible Valheim islands, but note that depending on your center the islands may look a bit different! It can take a sharp eye to pick out the similarities.