lightmapping confusion

deemccabe

Hi there, Im creating a light map for a shipping container i modelled. Im wondering should i keep this part as one single seamless piece on the UV sheet or should it broken into many peices on the UV sheet for lightmapping? and if your able to provide an answer can you explain why you would do it that way please.                                                                                                                                                 (this is the side of the container)I've very little experience creating light maps and through watching videos and reading some docs have found some conflicting information. Any help clarifying this would be much apprecaited

Obscura

You would want this to be one seamless uv island. The reason is that you would want relatively low lightmap resolution. And then if you split the uvs all over the place, you would likely get seams and bleeding at a lot of places, if not everywhere. So a seamless ones simply gives you much better result, especially when you work with lower lightmap resolution. So in this case, I'd go with one uv island. On something more complex, i would try to minimize the seams.

Why would you want this in any other way, other than the one uv island anyway? I can't think of a logical reason, if its the lightmap uv channel.

deemccabe

thank you very much for your reply. i created a light map just to see what it ended up like because i find it much easier to learn through doing. this is what i ended up with... i know it is terrible. do you have any advice, solutions or good links to articles that explain the light map process correctly. any help would be much appreciated.

heartlessph1l

A good place to start https://docs.unrealengine.com/latest/INT/Engine/Content/Types/StaticMeshes/LightmapUnwrapping/ 

and this http://www.worldofleveldesign.com/categories/udk/udk-lightmaps-01-basics-and-important-principles-for-creating-using-lightmaps.php

HAWK12HT

https://unity3d.com/learn/tutorials/topics/graphics/introduction-precomputed-realtime-gi

Though you are doing it in Unreal some of the core principals are same, Note in some case you have to break lightmap UV island at 90 degree angle etc similar to normal maps baking.