# Bug with directional lights and translucent sprite material (w shadows)

**URL:** <https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090>\
**Category:** Asset Creation\
**Tags:** sprites, Shadows, unreal-engine, bug-report, Lighting, question\
**Created:** [March 22, 2015, 5:40am UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090 "2015-03-22T05:40:03Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![anonymous\_user\_e5be9983](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_e5be9983](https://forums.unrealengine.com/u/anonymous_user_e5be9983)\
**Post date:** [March 22, 2015, 5:40am UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090/1 "2015-03-22T05:40:03Z")

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No matter what I do, every time I try to light a translucent sprite material with a directional light my sprite gets strange, black artifacts when I enable volumetric shadows. I’m pretty sure this is a bug or maybe it has something to do with self shadowing? I’m not sure.

Any help would be appreciated.

 ![34933-artifact2.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/0/7/3/073fa5438df10ec5f945aca4995d744976e9a48e.jpeg)

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**Author:** ![Tim\_Hobson](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tim\_Hobson](https://forums.unrealengine.com/u/Tim_Hobson)\
**Post date:** [March 24, 2015, 2:22pm UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090/2 "2015-03-24T14:22:26Z")

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Hi Johnny,

This is not actually a bug, but an artifact of using “cast volumetric translucent shadows” with highly opaque objects.

 ![35622-castvolumetrictransshadows.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/9/9/c99ff5ac870ae6b0ff280e36a9f1e3e6d927c9fc.png)

The better course of action here is to use a masked material to generate correct shading.

 ![35624-maskedvstranslucent.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/b/0/cb0229464dac89424292fb70d3caab6bcd8ab55a.png)

I hope this helps.

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<div class="post-metadata">

**Author:** ![anonymous\_user\_e5be9983](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_e5be9983](https://forums.unrealengine.com/u/anonymous_user_e5be9983)\
**Post date:** [March 24, 2015, 3:57pm UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090/3 "2015-03-24T15:57:10Z")

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Does this mean I cannot have a sprite that appears to “glow,” with high transparent edges, yet casts a shadow?

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**Author:** ![Tim\_Hobson](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tim\_Hobson](https://forums.unrealengine.com/u/Tim_Hobson)\
**Post date:** [March 24, 2015, 5:29pm UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090/4 "2015-03-24T17:29:57Z")

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You can use the emissive input to get your sprite to “glow.” In the examples below I just used the base color of my texture plugged into a multiply with a constant value of 1 in pin B. I then plugged the multiply into the emissive slot.

Here are the results and the problems that come with that.

Everything appears without the artifacts that cast volumetric translucent shadow causes.

 ![35642-glow1.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/5/0/2/502c7b89dbde249c65c5e5874faab976f8c6967a.png)

The problem comes in shadows. Since it’s using an emissive material shadows will hide the artifacts, but make it not possible to cast shadows onto your sprite.

 ![35643-glow2.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/5/6/c569474d3c60f5e5d2e62d98357615d0c342c1c0.png)

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<div class="post-metadata">

**Author:** ![anonymous\_user\_e5be9983](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_e5be9983](https://forums.unrealengine.com/u/anonymous_user_e5be9983)\
**Post date:** [March 25, 2015, 1:31am UTC](https://forums.unrealengine.com/t/bug-with-directional-lights-and-translucent-sprite-material-w-shadows/312090/5 "2015-03-25T01:31:59Z")

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Thanks for your help Tim! You’ve been great!