Lightmaps on large (tiled) terrains

What is a good approach and workflow for using Lightmass with a large terrain, or even tiled terrains using World Composer? I am pretty new to lightmap baking, I understand the basic principles and workflow, but am unsure how to apply that to terrains.

If I just run the baking without a Lightmass Importance Volume I get warnings that the scene is too large (and get artifact as warned). So, what to do? Does one single LMIV for the whole terrain improve the situation? Do you guys use several LMIVs per terrain (like 2x2)? And when using World Composer, would I have to load all tiles before running the light baking to make sure everything builds consistently (e.g. along the tile edges because there could be shadows from a mesh in one tile extend to the adjacent tile)?

Thanks for any advice!

What is the size of every tile? I’m not sure how light baking works with world composition but i personally would use dynamic lighting for a large world like that really.

Yes, I probably should give LPV a try. From what I here it isn’t exactly fast, though, and - more importantly - it doesn’t run on OSX currently.

The terrain would be 2x2 tiles, 4096 each.

Well, my suggestion is try both; baked lighting and LPV, and see which gives the best performance. You’ll have to cover the whole terrain with LMIV, it will take a long time to bild the lighting and lightmaps will require RAM(maybe more than you anticipated with a world that large) so it may cost performance to the end user more than LPV would.