# \#light-function **URL:** https://forums.unrealengine.com/tag/light-function/3139.md [Latest](https://forums.unrealengine.com/latest.md) · [Categories](https://forums.unrealengine.com/categories.md) · [Tags](https://forums.unrealengine.com/tags.md) --- ## [(5.6.1) Light function Material stops working when level starts, then remains off when exiting. ](https://forums.unrealengine.com/t/5-6-1-light-function-material-stops-working-when-level-starts-then-remains-off-when-exiting/2717475)
**Author:** [@Celestial\_Scythe](https://forums.unrealengine.com/u/Celestial_Scythe)\ **Replies:** 0\ **Last updated:** [April 23, 2026, 2:59pm UTC](https://forums.unrealengine.com/t/5-6-1-light-function-material-stops-working-when-level-starts-then-remains-off-when-exiting/2717475 "2026-04-23T14:59:06Z")
So I have a scene that has a light function material to create a flickering light effect. I use the same material for the emission on the object. When I first open the project, I can see the effect and it seems to functi… --- ## [Why does my light function material look pixelated in Unreal Engine ](https://forums.unrealengine.com/t/why-does-my-light-function-material-look-pixelated-in-unreal-engine/2657203)
**Author:** [@GaleVostro](https://forums.unrealengine.com/u/GaleVostro)\ **Replies:** 0\ **Last updated:** [September 16, 2025, 3:28pm UTC](https://forums.unrealengine.com/t/why-does-my-light-function-material-look-pixelated-in-unreal-engine/2657203 "2025-09-16T15:28:14Z")
--- ## [Is there any good way to have a light function contribute color to a light?](https://forums.unrealengine.com/t/is-there-any-good-way-to-have-a-light-function-contribute-color-to-a-light/1549509)
**Author:** [@Wheatttttt](https://forums.unrealengine.com/u/Wheatttttt)\ **Replies:** 1\ **Last updated:** [April 10, 2025, 7:05am UTC](https://forums.unrealengine.com/t/is-there-any-good-way-to-have-a-light-function-contribute-color-to-a-light/1549509 "2025-04-10T07:05:46Z")
I know that by default, light functions do not allow this, but is there genuinely no good way to do what I’d consider a very basic effect? I’ve read a post from 2015 that said UE3/UDK could do this, but that it would tak… --- ## [Issues with light function using rect light](https://forums.unrealengine.com/t/issues-with-light-function-using-rect-light/1283215)
**Author:** [@igorambrosio](https://forums.unrealengine.com/u/igorambrosio)\ **Replies:** 1\ **Last updated:** [March 26, 2025, 2:53pm UTC](https://forums.unrealengine.com/t/issues-with-light-function-using-rect-light/1283215 "2025-03-26T14:53:00Z")
I’m creating an immersive museum using light function with video textures to simulate a projector. This strategy worked really well with spotlights, but when I try to use it with rect light the texture only appears on a… --- ## [Raindrop Lght Function](https://forums.unrealengine.com/t/raindrop-lght-function/2354297)
**Author:** [@Pouyad](https://forums.unrealengine.com/u/Pouyad)\ **Replies:** 0\ **Last updated:** [February 24, 2025, 6:29am UTC](https://forums.unrealengine.com/t/raindrop-lght-function/2354297 "2025-02-24T06:29:14Z")
Hello folks! I REEEEAAAAALLLLYYY would love to know how I can make a clean light function like these raindrop effects in the video above. I’m still digging and have tried turning videos into texture, but have end… --- ## [UE 5.5.1 - Orthographic Camera and Light functions](https://forums.unrealengine.com/t/ue-5-5-1-orthographic-camera-and-light-functions/2270978)
**Author:** [@Pandemo](https://forums.unrealengine.com/u/Pandemo)\ **Replies:** 0\ **Last updated:** [January 11, 2025, 8:52am UTC](https://forums.unrealengine.com/t/ue-5-5-1-orthographic-camera-and-light-functions/2270978 "2025-01-11T08:52:05Z")
Hi everyone, After updating my project to 5.5.1 I ran trough some tests to see what has been updated from 5.4 for the Orthographic camera. I’m very happy to see that all jittering and UI issues from 5.4 have been solved… --- ## [How to stop Light Functions from projecting through meshes?](https://forums.unrealengine.com/t/how-to-stop-light-functions-from-projecting-through-meshes/457992)
**Author:** [@TorQueMoD](https://forums.unrealengine.com/u/TorQueMoD)\ **Replies:** 3\ **Last updated:** [October 9, 2024, 1:56am UTC](https://forums.unrealengine.com/t/how-to-stop-light-functions-from-projecting-through-meshes/457992 "2024-10-09T01:56:16Z")
I’ve created a custom Light Function for water caustics in my game, but the light function is projecting through the walls and floors of my map. The geometry is solid (not built with planes) and I’m not using any static … --- ## [substrate](https://forums.unrealengine.com/t/substrate/2035073)
**Author:** [@DisassociateTTV](https://forums.unrealengine.com/u/DisassociateTTV)\ **Replies:** 0\ **Last updated:** [September 24, 2024, 3:41am UTC](https://forums.unrealengine.com/t/substrate/2035073 "2024-09-24T03:41:16Z")
How do I make a simple light function for my media player material with substrate? I can’t find anything useful in the documentation. I’m just trying to make a light function for TV glow. --- ## [Reading/Getting the output from a light function in BP](https://forums.unrealengine.com/t/reading-getting-the-output-from-a-light-function-in-bp/1564632)
**Author:** [@MickyPain](https://forums.unrealengine.com/u/MickyPain)\ **Replies:** 2\ **Last updated:** [August 30, 2024, 9:15am UTC](https://forums.unrealengine.com/t/reading-getting-the-output-from-a-light-function-in-bp/1564632 "2024-08-30T09:15:51Z")
So, I’m working on some prototypes for a universal light flicker BP that I can use for any fires, torches or candles. The actual light flicker I like best comes from a light function material attached to a point light, … --- ## [spot light, rectangle light functions not affecting fog](https://forums.unrealengine.com/t/spot-light-rectangle-light-functions-not-affecting-fog/455065)
**Author:** [@hadijam](https://forums.unrealengine.com/u/hadijam)\ **Replies:** 3\ **Last updated:** [July 29, 2024, 8:20pm UTC](https://forums.unrealengine.com/t/spot-light-rectangle-light-functions-not-affecting-fog/455065 "2024-07-29T20:20:30Z")
Hello I see that light function material doesn’t effect the exponential fog . is there any setting or material maybe that I need to tweak? thank you in advance 286784- \]\[1\] --- ## [Tiling Flipbook Textures - Is there a way to only tile the UV space sample on one frame of the sheet?](https://forums.unrealengine.com/t/tiling-flipbook-textures-is-there-a-way-to-only-tile-the-uv-space-sample-on-one-frame-of-the-sheet/335841)
**Author:** [@StormAndy](https://forums.unrealengine.com/u/StormAndy)\ **Replies:** 6\ **Last updated:** [March 26, 2024, 4:35pm UTC](https://forums.unrealengine.com/t/tiling-flipbook-textures-is-there-a-way-to-only-tile-the-uv-space-sample-on-one-frame-of-the-sheet/335841 "2024-03-26T16:35:47Z")
Hey guys, I’m having an bit of technical art dilemma here with my modular environment art. I need to Tile the end result of the my animated flipbook textures in the material editor. To do this i Must use animated textur… --- ## [Volumetric Light Function](https://forums.unrealengine.com/t/volumetric-light-function/478636)
**Author:** [@SEEEMOTIOM](https://forums.unrealengine.com/u/SEEEMOTIOM)\ **Replies:** 2\ **Last updated:** [July 22, 2023, 6:45pm UTC](https://forums.unrealengine.com/t/volumetric-light-function/478636 "2023-07-22T18:45:18Z")
Hello I want to achieve volumetric spot light beam with multiple beams instead of just one whole beam. I wonder if its possible to produce volumetric light beams from the light function material - for example have a… --- ## [\[BUG REPORTED\] Camera Position doesnt work with Light Function](https://forums.unrealengine.com/t/bug-reported-camera-position-doesnt-work-with-light-function/470884)
**Author:** [@LethalDumpster](https://forums.unrealengine.com/u/LethalDumpster)\ **Replies:** 9\ **Last updated:** [March 24, 2023, 3:39pm UTC](https://forums.unrealengine.com/t/bug-reported-camera-position-doesnt-work-with-light-function/470884 "2023-03-24T15:39:21Z")
Can you elaborate on how its not working or share the context in which you are trying to use the the camera position node in a material? I just tested and verified and it appears to be working: --- ## [Colored image in light function](https://forums.unrealengine.com/t/colored-image-in-light-function/448630)
**Author:** [@anonymous\_user\_152a96ab](https://forums.unrealengine.com/u/anonymous_user_152a96ab)\ **Replies:** 3\ **Last updated:** [February 20, 2023, 12:48pm UTC](https://forums.unrealengine.com/t/colored-image-in-light-function/448630 "2023-02-20T12:48:55Z")
Hello Folks, Is it possible to input a full color texture into a light function for a movable spotlight? I’ve only had success with greyscale. Also hoping to have it work in volumetric light. --- ## [SSAO not working with my light function](https://forums.unrealengine.com/t/ssao-not-working-with-my-light-function/601317)
**Author:** [@Nerf\_My\_Thumbs](https://forums.unrealengine.com/u/Nerf_My_Thumbs)\ **Replies:** 1\ **Last updated:** [January 10, 2023, 9:59pm UTC](https://forums.unrealengine.com/t/ssao-not-working-with-my-light-function/601317 "2023-01-10T21:59:21Z")
Hey everyone, I have a light in my scene that’s using a light function material and has “cast shadows” disabled. I noticed that as soon as I turn on my light function, SSAO is completely erased from my scene. Does anyone… --- ## [custom light function in c++](https://forums.unrealengine.com/t/custom-light-function-in-c/490284)
**Author:** [@Chrizzo](https://forums.unrealengine.com/u/Chrizzo)\ **Replies:** 0\ **Last updated:** [October 26, 2021, 8:19pm UTC](https://forums.unrealengine.com/t/custom-light-function-in-c/490284 "2021-10-26T20:19:42Z")
Hello everyone, I need a projector effect, which projects a colored movie sequence on a wall. Because light functions can only alter the brightness values and not the color values of a light I used the work around with … --- ## [How To Mask A Light Function Above A Certain Height?](https://forums.unrealengine.com/t/how-to-mask-a-light-function-above-a-certain-height/487694)
**Author:** [@TheHammerSV](https://forums.unrealengine.com/u/TheHammerSV)\ **Replies:** 0\ **Last updated:** [August 23, 2021, 9:34pm UTC](https://forums.unrealengine.com/t/how-to-mask-a-light-function-above-a-certain-height/487694 "2021-08-23T21:34:24Z")
Hello! I am using a light function to create an underwater caustics effect. I like how it looks to see the caustics from above the water line as well, but my issue is that the light function affects everything above the … --- ## [I cannot place light function at all lights that present in my level](https://forums.unrealengine.com/t/i-cannot-place-light-function-at-all-lights-that-present-in-my-level/486128)
**Author:** [@sayooj\_js](https://forums.unrealengine.com/u/sayooj_js)\ **Replies:** 0\ **Last updated:** [July 13, 2021, 3:46am UTC](https://forums.unrealengine.com/t/i-cannot-place-light-function-at-all-lights-that-present-in-my-level/486128 "2021-07-13T03:46:31Z")
I don’t understand why I can’t place light function to all types of lights that present at my level. I have checked alternative material, but it didn’t, Also I have checked with another project, it did work. But for some… --- ## [Volumetric fog masking incorrect with worldspace based Light Function](https://forums.unrealengine.com/t/volumetric-fog-masking-incorrect-with-worldspace-based-light-function/453898)
**Author:** [@Arnage](https://forums.unrealengine.com/u/Arnage)\ **Replies:** 1\ **Last updated:** [August 20, 2019, 7:16pm UTC](https://forums.unrealengine.com/t/volumetric-fog-masking-incorrect-with-worldspace-based-light-function/453898 "2019-08-20T19:16:06Z")
When using worldspace masking inside a light function the masking is applied incorrectly to volumetric fog. An example can be seen in the following image: The associated light function looks like this: Reproductio… --- ## [Light Function material and Cubemaps](https://forums.unrealengine.com/t/light-function-material-and-cubemaps/442862)
**Author:** [@anonymous\_user\_d97d3e2e](https://forums.unrealengine.com/u/anonymous_user_d97d3e2e)\ **Replies:** 6\ **Last updated:** [July 19, 2019, 5:35pm UTC](https://forums.unrealengine.com/t/light-function-material-and-cubemaps/442862 "2019-07-19T17:35:39Z")
Hello, I’m trying to get fake shadows from a lamp using a material light function. I’m already using simple light functions with spotlights and 2D textures, but I would like to push that more, using point lights and cub… --- ## [Light Materials](https://forums.unrealengine.com/t/light-materials/436633)
**Author:** [@Dark\_Jubei](https://forums.unrealengine.com/u/Dark_Jubei)\ **Replies:** 3\ **Last updated:** [November 1, 2018, 12:28pm UTC](https://forums.unrealengine.com/t/light-materials/436633 "2018-11-01T12:28:40Z")
you can use every channel of colored texture as light function of the same light color. So create 3 light sources - red, green, and blue, and use 3 material instances with masked r/g/b texture channels, as their light f… --- ## [Light function does not work when "Cast Shadows" or "Cast Dynamic Shadows" is disabled](https://forums.unrealengine.com/t/light-function-does-not-work-when-cast-shadows-or-cast-dynamic-shadows-is-disabled/412087)
**Author:** [@anonymous\_user\_fc6e0fe5](https://forums.unrealengine.com/u/anonymous_user_fc6e0fe5)\ **Replies:** 1\ **Last updated:** [October 5, 2018, 4:14pm UTC](https://forums.unrealengine.com/t/light-function-does-not-work-when-cast-shadows-or-cast-dynamic-shadows-is-disabled/412087 "2018-10-05T16:14:44Z")
For my current project I’m using a MediaTexture as LightFunction to light a room. This works great as long as the lightsource (in my case a Spotlight) is dynamic and has “Cast Dynamic Shadows” and “Cast Shadows” enabled.… --- ## [Light function - projected image offset](https://forums.unrealengine.com/t/light-function-projected-image-offset/431705)
**Author:** [@joelbenjamin](https://forums.unrealengine.com/u/joelbenjamin)\ **Replies:** 7\ **Last updated:** [August 16, 2018, 3:43pm UTC](https://forums.unrealengine.com/t/light-function-projected-image-offset/431705 "2018-08-16T15:43:01Z")
I have a light with a light function material, that’s basically having the light project an image. My issue is - the light is tiling the image when it’s projecting it, and it’s offset from the center of the light - basi… --- ## [Light Functions and hierarchical instanced mesh banding](https://forums.unrealengine.com/t/light-functions-and-hierarchical-instanced-mesh-banding/424487)
**Author:** [@Gampersnaz](https://forums.unrealengine.com/u/Gampersnaz)\ **Replies:** 2\ **Last updated:** [May 11, 2018, 11:48am UTC](https://forums.unrealengine.com/t/light-functions-and-hierarchical-instanced-mesh-banding/424487 "2018-05-11T11:48:55Z")
Hi there, I have made a rather large ocean using a smaller detailed water plane with LODs that I have tiled in x and y using a blueprint in it’s construction script. It looks great and the performance is awesome. However… --- ## [Video in Light Function no longer working](https://forums.unrealengine.com/t/video-in-light-function-no-longer-working/410207)
**Author:** [@zuthyrus](https://forums.unrealengine.com/u/zuthyrus)\ **Replies:** 18\ **Last updated:** [February 22, 2018, 11:33am UTC](https://forums.unrealengine.com/t/video-in-light-function-no-longer-working/410207 "2018-02-22T11:33:17Z")
Hello, Since updating to 4.18, I have discovered that Video / Media files don’t seem to be working with the Light Function material any more. I am trying to project a video file using a spot light actor, onto people st… --- ## [Making a point light have a hard edge, or light falloff](https://forums.unrealengine.com/t/making-a-point-light-have-a-hard-edge-or-light-falloff/405341)
**Author:** [@TheCuddlyRoman](https://forums.unrealengine.com/u/TheCuddlyRoman)\ **Replies:** 3\ **Last updated:** [September 24, 2017, 4:24pm UTC](https://forums.unrealengine.com/t/making-a-point-light-have-a-hard-edge-or-light-falloff/405341 "2017-09-24T16:24:16Z")
Hey guys, I’ve been having an issue making point lights in ue4 have a hard edge, so instead of fading off from their most intense point to 0, it is the same brightness until it hits a certain distance away from the cente… --- ## [4.17 Forward Rendering: Light Functions dont work with non shadow casting lights](https://forums.unrealengine.com/t/4-17-forward-rendering-light-functions-dont-work-with-non-shadow-casting-lights/404660)
**Author:** [@OpticalShadows](https://forums.unrealengine.com/u/OpticalShadows)\ **Replies:** 0\ **Last updated:** [September 15, 2017, 3:20pm UTC](https://forums.unrealengine.com/t/4-17-forward-rendering-light-functions-dont-work-with-non-shadow-casting-lights/404660 "2017-09-15T15:20:07Z")
This only seems to be a problem with the forward renderer. Steps to reproduce: Create a new project and enable forward rendering. Create a basic light function material (I used a simple noise node) Create a point ligh… --- ## [Light Function not working in PIE](https://forums.unrealengine.com/t/light-function-not-working-in-pie/402360)
**Author:** [@anonymous\_user\_416b781b](https://forums.unrealengine.com/u/anonymous_user_416b781b)\ **Replies:** 3\ **Last updated:** [September 1, 2017, 9:28pm UTC](https://forums.unrealengine.com/t/light-function-not-working-in-pie/402360 "2017-09-01T21:28:59Z")
I’m using a light function to render clouds on a landscape. The rendering of the light function works fine in the realtime editor screen, but not when playing in the editor. I’ve made a video for demonstration: Dropbox … --- ## [Light Functions in 4.16 Broken?](https://forums.unrealengine.com/t/light-functions-in-4-16-broken/401113)
**Author:** [@reedandrader](https://forums.unrealengine.com/u/reedandrader)\ **Replies:** 0\ **Last updated:** [August 3, 2017, 6:53pm UTC](https://forums.unrealengine.com/t/light-functions-in-4-16-broken/401113 "2017-08-03T18:53:08Z")
Hey all, I upgraded a project from 4.15 to 4.16 and all my light functions no longer work. Did I miss something with the new version? --- ## [Rotating Directional Light just stretches Light Function from centre](https://forums.unrealengine.com/t/rotating-directional-light-just-stretches-light-function-from-centre/395947)
**Author:** [@anonymous\_user\_705e34d1](https://forums.unrealengine.com/u/anonymous_user_705e34d1)\ **Replies:** 2\ **Last updated:** [June 9, 2017, 7:09pm UTC](https://forums.unrealengine.com/t/rotating-directional-light-just-stretches-light-function-from-centre/395947 "2017-06-09T19:09:41Z")
I am trying to set up a rotating sun / directional light with a light function for cloud shadows. When I rotate the sun actor around the X or Y axis the light function is stretched in the same direction, regardless of … [Next page](https://forums.unrealengine.com/tag/light-function/3139.md?match_all_tags=true&page=1&tags%5B%5D=light-function)