unlit + lightmap material type

another caveman

one more lightmapping thread ? yes ! 
I'm looking to have lightmaps on the Unlit material type.. I read on the UE forums that's a custom material type to compile.. Not sure how to get there.
Any resource or knowledge to share? thanks!

another caveman

https://medium.com/@lordned/ue4-rendering-part-6-adding-a-new-shading-model-e2972b40d72d