Lightmaps vs lightmass

Hey everyone,

I was wondering if anyone would kindly share a concise and simplified explanation of the difference between lightmaps created in external software and lightmaps created by lightmass in Unreal, also the pros/cons to inform me which to use and when.


There’s only 1 type of lightmap. It is usually created in your modelling package. It’s just a uv channel with the geometry carefully unwrapped. Basically it’s a texture that unreal will use to draw all the shadows on. Unreal’s renderer is called lightmass (like vray or mental ray or octane, etc) and it’s what gonna bake all those shadows on your object’s lightmaps. Hope my explanation isn’t too confusing. English isn’t my mother tongue !

mmm AFAIK, if you want generate lightmaps from lets say, 3dmax, you lost your second UV channel, and that becomes in extra work in order to create tilled materials, not a big deal, but it’s a real issue, because unreal does not allow even save very well their own lightmaps from lightmass for reload for example, so the only way to implement your lightmap from (3dmax) is through materials, and it will difficult to achieve, because lightmap is not just white and black images multiply in top of materials,