Why are my Static Meshes black even though lit?

Development Rendering
, , , ,
1

I’ve been having this difficulty in my main projects, so I decided to make a small project in which to test the lighting for quicker turnover with light builds.

As you can see ( in the bottom picture ), the static meshes are all normal under preview settings, but, when the lighting is built ( in the top picture ), it turns most of the meshes black, and some, like the bookcase behind, become very splotchy.

I’ve seen other threads asking about this and have tried the fixes they mentioned - I generated other UV layers to make sure there was a UV layer 1 and 2, and I also reimported these meshes with the normals calculated by UE. I also tried changing the lightmap resolution, to no avail.

I’m at a loss. What am I missing?

://i.imgur/MVUpkx4.png

://i.imgur/NRBz233.jpg

2

Have you generated the 2nd uv channel in the UE4 or outside in a 3d program? + do you get any errors when you build the light?

Because normally this should be solved with a 2nd uv channel + proper lightmap :slight_smile:

3

I generated the second ( and even a third ) UV channel within UE4. I get an error about the .fbx missing smoothing information on one of the items, but, seeming as it’s not on all the items, I figured it was unrelated to whatever is causing this.

4

I have no idea how to do that. What would the other program do that UE4 isn’t capable of?

I get the distinct feeling that this is an issue with some setting with the lighting or the UV within UE4.

5

Create the lightmap in a 3d program and then test out if the meshes will be still black

6

When you send me the file I can test it out for you → it does the same as the UE4, but I think just in a better way (out of experience the generating in the ue4 fails most of the time)

When you like you can send it to me as a pm in the forum:

7

Sent you a PM. Thanks for helping with this.

8

Another thing could be that you use roughness and metallic in your material → add a sphere reflection capture node

9

I checked the roughness and metallic settings for each material and tweaked them in a bunch of ways and it had no effect. I hadn’t tried it with the sphere reflect capture node, but would that even matter if the metallic was set to 0 ( or 1, I forget which means it’s not reflective )?

10

Alright. I see what you’re saying. I tried it like you mentioned and it didn’t seem to do the trick. I shot you a link to one of the models in a PM, if you still were willing to take a look at it. :slight_smile:

11

1 roughness → no reflection. I would try out the way with the reflection capture actor, because I think there are just two ways why your mesh is black. Either the reflection or because of the 2nd uv channel :slight_smile:

12

Ok, I tried out various stuff, but somehow I can’t find out what is wrong, because in my case it works → so it must be the material or your light setup. Could you probably post a screenshot of your mat + information about the light setup? Here is a modified version of your mesh (you haven’t unwrapped your model) https://drive.google/file/d//edit?usp=sharing

11265-table.jpg

13

Alright, I grabbed that model and looked at it, and the one glaring difference between the model I sent to you and the model you sent back is that the original had 3 materials assigned to different parts of the mesh ( one for the desktop, one for the body, and one for the legs ). The one you sent to me is comprised of only one material ( one solid UV, whatever ).

14

I’m building the lighting as I type this. Will post results in one moment.

15

Here ya go. Looks like it gathered the light just fine, so it’s not the lighting in the scene, then, right?

://i.imgur/TcHAWCF.png

16

Yep, I know ^^ + it has a 2nd uv channel → but is it still black?

17

Then it’s the 2nd uv channel that I created in blender ^^ → (I did it the same way as in this video)

18

You can use the generator in the UE4, but mostly you dont get a good result ^^ So it’s recommended to do it in a 3d program (my way which is shown in the video isn’t the best way, but you will have a good result in the end + it’s really easy)
Here is the theory behind 2nd uv channels + lightmap:

19

Alright, I kinda understand what you’re saying, but not fully. I will attempt to try the steps laid out in the tutorial you linked, but can you explain to me why this problem is happening and why I can’t just use the UV generator in UE4?

Again, if I haven’t said so enough - thank you so much for all of this help. :slight_smile:

20

so why do you have to make a second UV channel anyway? is that something you do if you didn’t unwrap it without overlaps?
or is this like a blender specific thing that happens? because you could always try exporting your models from blender to another program and unwrapping them in that then exporting to fbx from there.