Completely new to modelling: Wonky shadows and shaders in UE4, questions regarding textures

So, I’ve yet again decided to try UE4 as a more powerful replacement, or at least subsidiary, for Source and Hammer, the main drawback being that it relies on meshes for pretty much everything, the creation of which I know pretty much fuck all about.
So I read and watched a couple of guides, fired up blender, and exercised by creating some of my first 3D-models. In blender they look fine, but as soon as they’re imported into UE, and especially once the lighting has been built, the flaws become pretty apparent:

Unbuilt scene, looks pretty okay, although some wonkery can be seen

https://i.imgur.com/Q0xbhqJ.jpg[/t]

Built scene, lots of strange blotches and broken shadows
[t]https://i.imgur.com/kxTIOie.jpg[/t]

Close-up of blotches on the wooden strip thing:
[t]https://i.imgur.com/WMIm6iQ.png[/t]

Wooden strip thing with alternate material applied to showcase the shading problems it also suffers from:
[t]https://i.imgur.com/LxfElE2.png[/t]

Window with unbuilt lighting, looks alright
[t]https://i.imgur.com/Wytm6XY.png[/t]

Lighting built, window turns into some sort of double slit experiment
[t]https://i.imgur.com/lopvkFN.png

I’d assume that the shading problems are due to improper smoothing , while the strange blotches and corrupted shadows are due to the UV maps?
But what is it I’ve done wrong?

Link to the models:
https://1drv.ms/u/s!ArpYfqiR7flciBQHTM1Li41fXe56
(MS OneDrive)
(And yes, they’re complete masterpieces from a geometrical and optimization standpoint. Especially the wooden strip, crème de la crème).

I also have no real idea of how I’m supposed to properly manipulate the textures on a mesh. The information I’ve gathered from the web are sort of conflicting, some say the textures should be applied and baked in Blender, others say Blender/3DSMax, etc. should only be used for creating the geometry, while the textures should be applied in-Engine. I found texturing to be relatively straight-forward in Blender, but I can’t get UE to import them, and texturing in UE has been a complete nightmare so far.

i only saw this thread on the popular page under latest threads, a lot of fp’s 3d artists don’t really browse the modelling section so i suggest hitting up http://forum.facepunch.com/showthread.php?t=1543439&page=47 and the discord https://discord.gg/GeYM8A for other questions

so the problems you’re seeing are due to either the lightmap UV’s or lightmap resolution in unreal. before the lighting is built the shadows are calculated dynamically at a very high resolution which is why you aren’t seeing any artifacts. once you do a lighting build, the shadows are baked into lightmap textures for performance reasons - but by default the lightmap res for the majority of meshes is quite low. in most cases this is fine, but sometimes you’ll get artifacts like you’re seeing

you can change that in the right side menu when you’ve got a mesh selected in the world, or by selecting a mesh in the library and double clicking it and changing it in there (it then applies that lightmap res for any instance of the mesh used)

for complex scenes and full production you’ll need to be creating a separate UV map just for the lightmaps. however, for small things like this UE4 has a built in lightmap generator that isn’t perfect but works well enough. you can view/delete the auto generated lightmaps by double clicking a mesh in the library, toggling the UV button and using the drop down

(sorry about the fps overlay)

hope that helps a bit. lots of good folks in the discord that will help you out if you’ve got any little issues

Alright, thanks a ton. I’m still not sure what to do with the auto generated lightmaps, but I’ll take this to the Discord channel and the other thread.