# Invisible VrayLight  is slightly visible through fog refract object.

**URL:** <https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480>\
**Category:** Issues\
**Created:** [March 8, 2013, 8:43am UTC](https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480 "2013-03-08T08:43:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Kakashi](https://avatars.discourse-cdn.com/v4/letter/k/ac91a4/32.png) [@Kakashi](https://forums.chaos.com/u/Kakashi)\
**Post date:** [March 8, 2013, 8:43am UTC](https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480/1 "2013-03-08T08:43:16Z")

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Hi.

I make a scene that there is a invisible VrayLight and plane applied for refract fog vraymtl.

A rendering result is that a invisible VrayLight is slightly visible through refract plane.

This scene’s point is that Fog bias is not zero.  
If Fog bias is zero, VrayLight is invisible.

Is this bug?

Test scene is  
[Visible\_Invisible\_VrayLight\_through\_FogRefractionObj.zip](https://forums.chaos.com/uploads/short-url/6LoFY9oiFMTDEJohgEyHnLiUhti.zip) (104 KB)

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**Author:** ![Zdravko](https://avatars.discourse-cdn.com/v4/letter/z/ba8739/32.png) [@Zdravko](https://forums.chaos.com/u/Zdravko)\
**Post date:** [March 11, 2013, 3:26pm UTC](https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480/2 "2013-03-11T15:26:17Z")

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To get a proper result when using VRayMtl fog color you will need to make sure the geometry have volume.

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<div class="post-metadata">

**Author:** ![Kakashi](https://avatars.discourse-cdn.com/v4/letter/k/ac91a4/32.png) [@Kakashi](https://forums.chaos.com/u/Kakashi)\
**Post date:** [March 12, 2013, 6:18am UTC](https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480/3 "2013-03-12T06:18:26Z")

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I changed the geometry that have volume.  
But the invisible VrayLight is slightly visible.

Please check a scene again?  
[Visible\_Invisible\_VrayLight\_through\_FogRefractionObj\_ver2.zip](https://forums.chaos.com/uploads/short-url/9XMIPViIqe3a9kTbuLT48GLBlJA.zip) (95.8 KB)

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<div class="post-metadata">

**Author:** ![Zdravko](https://avatars.discourse-cdn.com/v4/letter/z/ba8739/32.png) [@Zdravko](https://forums.chaos.com/u/Zdravko)\
**Post date:** [March 12, 2013, 8:16am UTC](https://forums.chaos.com/t/invisible-vraylight-is-slightly-visible-through-fog-refract-object/44480/4 "2013-03-12T08:16:39Z")

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Yes, you are right. We made a note about that.  
For now you can workaround the problem by making sure the light is positioned out of the glass object.

Thank you for the feedback.