Rect Light with textures broken in 5.1?

Hi.

I posted this on Reddit, but received no response. So I’ll try my luck here instead.

Whenever I try to light a scene with a texture using a Rect Light in 5.1 I get no output from the rect light - no matter how high I set the intensity.

It worked fine in 5.0.

The Rect light also works fine using a color and temperature in 5.1.

Can someone replicate this error? Or did I simply forget to tick a box somewhere after the update?

1 Like

hi.
Reinstall the 5.1 , Rect Light can work normal :grinning:

Hi.

I tried that. Unfortunately, it didn’t fix the issue.

Is this a known bug?

Are you using Forward Shading Renderer? Rect light does not work with forward shading (you can check if you are using forward shading by searching it in the Project Settings)

2 Likes

Thank you for the suggestion. Unfortunately, that’s not it either. The Rect light works fine - but not with textures.

Could anyone please try to replicate this error?

It’s impossible to replicate the issue with the info you provided. Provide some steps to replicate the issue, some images, etc. Right now it’s only possible to guess: are you using Lumen? Are you using movable or static/stationary lights?

Okay. Here is the problem in more detail:

I like to use Rect light with source textures to light city scenes.

Here’s what I get in 5.0 and what I expect:

Here’s what it looks like in 5.1:

The light doesn’t recognize the texture. Rect light works fine in 5.1 with color but not with source texture.

Here are the light project settings (I use Lumen):

Is this is enough to replicate the issue?

Can someone get it to work from the images above? Or are you running into the same issue as me?

hey there, I can definitely confirm having the same issue with 5.1

I made a post about it too, as far as I know there’s no fix yet… very annoying, in automotive lighting I’m relying on RectLights a lot, this is basically breaking a lot of my scenes.

Hi.

I’m glad I’m not the only one experiencing this. I’ve recently submitted a bug report about it to Epic Games after having gone back and forth between 5.0 and 5.1 to double-check all the settings. Let’s hope they fix it in the next update.

Same problem here. If I apply a source texture, the rectlight emmits a kind of average of the texture as light. you can not see the texture. i have 5.1.1 installed.
everything is working as expected in 5.0.3 … Has someone a suggestion how to fix this?

1 Like

Just an update. I could see that my bug report wasn’t in Epic’s list over bug reports. So I’ve tried submitting it again.

Maybe we can get this resolved faster if more submit it.

Don’t worry, you will be ignored.

I can confirm this issue too. I have tested it in the UE5 main branch (5.3.0) and it’s still happening.

As you pointed, in 5.0 is working well as in UE4 (even if it wasn’t perfect too), but since 5.1, it doesn’t.

The most similar bug report I think is this one:

Let’s vote it!

2 Likes

I have now gotten a reply from Epic stating that they could replicate the error. But also, I shouldn’t expect it to be prioritized (which I think they write to everyone). So fingers crossed it will be fixed in the next update. It should be a simple fix since it already worked in 5.0.

Great. In fact, the bug report link I posted, is now marked as Fixed, so maybe it’s already ready to come in the next 5.2 release (even if it says to be expected for 5.3)

also Just confirming that from my end, 5.1.1 doesnt do rec light source textures for me at all.

similarly, I work in automotive field, and this one break actually makes Unreal 5.1 completly unusable for any of our design work.
(you basically use rec lights with textures exclusivly when studio lighting cars) .

this one is a major ball drop on Epics acount.

further more, to make it worse,
it was working in 5.1 ( did a whole project in it)

then Unreal auto updated to 5.1.1 and it stopped working,

no easy way to role back to 5.1

Yeah, I read that it was confirmed and fixed. I hope we get the fix implemented in 5.2, but the target fix said 5.3: Unreal Engine Issues and Bug Tracker (UE-180145)

Actually , Id like to update my last response,
for 5.1, I found that as long as the texture is 8bit and jpg,
it seemed to start working again for me. though i understand this doesnt fix things for people wanting the 32 bit tiffs or exrs to get the detain in the light texture, it is a bandaid until a proper fix comes around

1 Like

thanks @Darmelli had had the same issue for so long and your fix for it just to be a jpeg worked. nice one!

I can confirm that it has been fixed in 5.2