Imported FBX lighting/shadows issues

Hi all,

beginner here…!

I’ve imported a large room in two pieces, floor and walls with ceiling. The meshes are clean and have no problems. The UVs are also fine.

But, when I import them into UE I get the following kind of artifacts/irregularities… things like the weird lighting/shadowing at the edges and also those dark spots where there aren’t any vertices too?
Also the shadows of the little sticking out pillars fall short of their geometry on 02_A?

The A screenies are in UE, the Bs are in Maya so you can see the wire frames.

Does anyone know why any of this is or how I can remedy it please?
I’m using the 3rd Person BP almost at it’s default settings, the only thing I’ve hanged is the graphics are all on Ultra.

ANY help with this will be much appreciated…!


This is probably due to overlapping UVs. If not, perhaps you haven’t created a second uv channel for your lightmap?

Hi man,


The UVs should be fine as I laid them out in Maya and there’s no overlapping, but as fr as the second channel goes, do I do that to the FBX in Maya or when it’s in UE?
Could it be the resolution of the lightmap generated in UE?

I’m going to be building some pretty big but cleanly built structures so I need to resolve this early…!

Ok, so I upped the Lightmap resolution to 4096 (!) and it’s improved it, but obviously I don’t want to use a Lightmap this size so does anyone else have any suggestions/help please?

Also on the second screenie you can see there’s also some weird issue with the shadows cast by those thin tall pillars again? Does anyone know why this could be?

Thanks guys.


The weird shadows cast from those pillar shapes are due to the ceiling being one-sided, the light is coming through from outside. For interiors it helps if you have an outside facing surface to block lighting, it doesn’t need to be detailed if you don’t want to see the outside, just something to block the light.


Your mesh is huuuuge!! :smiley:
…you should break it into (modular) pieces and then you can use smaller lightmaps on them…
…or dynamic lighting :S!

To be honest I got tired of having those issues, even though my UVs were also perfectly laid out. I don’t have to worry about this kind of stuff (and build times) now that I’m using dynamic lighting. Give it a try, make sure to set all of your lights (including sky light and light source) to movable directly afterwards, otherwise you’ll have some huge framerate issues. Some people say it’s taking more ressources, but I don’t see any difference tbh.

Dynamic lighting will use more processing power and doesn’t look as nice, you don’t get bounce lighting from dynamic lights.

Hi guys and girls,

thanks for the replies…!

@darthviper108- yes, I found this out by ticking on the “make double sided” (I can’t remember the correct name), which instantly had the desired effect of fixing those shadows and also making the room look darker which is what I was also after. Baby steps in UE4…!!! :wink:

@ Makigirl- yeah, I know, but ideally as this is going to be pretty stylized I’d like to be able to leave the meshes pow poly counts where I can. I know to break them up when they obviously get too stretched out, but generally there will be a lot of these big structures I want to make with simple low poly forms etc.

@darthviper107- ■■■■, that’s a shame, as I was hoping for some nice bounced lighting in this… I’ll have to see what I can do within the confines of dynamic lighting… I wonder if there’s any compromise to be had?

Within UE4 there’s a system called Light Propagation Volumes (LPV) it does dynamic GI, however, the detail is poor and it only works with the directional light and emissive textures.
There’s also VXGI from Nvidia, but that requires building the VXGI build they have available which gives you a version of the editor with it integrated

Thanks man, that’s a bit far ahead of where I’m at right now but eventually I might get up to that point. Seems a bit lacking it only works under those conditions though.

To sum up, in GENERAL, is it taken for granted that if you’re going to have a real time of day system in your world then you’re going to basically be using dynamic lighting for the majority?

If you need a day/night cycle then you don’t have any other option. It’s easier if you’re doing exterior maps, but interior lighting depends a lot on nice bounce lighting and often looks poor in open-world games.

Hey man, I cannot reply to your PM because of some glitch (404 error), but here’s my reply.

I am not an expert on lighting, far from that so I’m afraid I can’t give you much info. :frowning: Basically, after enabling dynamic lighting, I have set all of my lights to movable (by clicking them, then selecting “movable” on the menu on the right, under the transform tab). Do the same on your meshes. However, try to avoid selecting all the objects of your level at once to set them to movable simultaneously. It gave me issues afterwards (collision issues, scripts that stopped working, I had to recreate them).

About the way to build a level, here’s how I do it. I create the walls, then the ceiling as a separate mesh, and the floor as a separate mesh, then import them inside unreal. You must not create the walls, floor and ceiling as a single mesh, it will often give you collision issues. Since your walls and floors are irregular, then it could be a good idea to use a modular workflow. Basically, you break everything into pieces (walls, windows, ornaments, walls) and you build your level with them, by copy/pasting them.

Here’s a perfect exemple of this workflow

Also, make sure that your floor/walls/stairs collision are set this way

Otherwise, your character won’t be able to walk up stairs and walk through doors.