# 4.17 Forward Rendering: Light Functions dont work with non shadow casting lights

**URL:** <https://forums.unrealengine.com/t/4-17-forward-rendering-light-functions-dont-work-with-non-shadow-casting-lights/404660>\
**Category:** Rendering\
**Tags:** UE4-17, Shadows, light, light-function, unreal-engine, Lighting, question\
**Created:** [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")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![OpticalShadows](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@OpticalShadows](https://forums.unrealengine.com/u/OpticalShadows)\
**Post date:** [September 15, 2017, 3:20pm UTC](https://forums.unrealengine.com/t/4-17-forward-rendering-light-functions-dont-work-with-non-shadow-casting-lights/404660/1 "2017-09-15T15:20:07Z")

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This only seems to be a problem with the forward renderer.

Steps to reproduce:

1. Create a new project and enable forward rendering.
2. Create a basic light function material (I used a simple noise node)
3. Create a point light in the scene .
4. Apply Light function material to light.
5. Toggle the **Cast Shadows** box on and off to see the effect appear and disappear.

It makes no difference if the light is static or dynamic.  
I’ve attached a screen shot of two point lights, the left one doesn’t cast shadows and the right one does.

 ![213612-capture.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/b/9/f/b9f57f3d2937655f829297f5edbba68cd5f2aa7f.jpeg)