# Transparent material appears black when using lightmap

**URL:** <https://forum.babylonjs.com/t/transparent-material-appears-black-when-using-lightmap/38394>\
**Category:** Questions\
**Created:** [February 21, 2023, 6:19am UTC](https://forum.babylonjs.com/t/transparent-material-appears-black-when-using-lightmap/38394 "2023-02-21T06:19:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![joie](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/joie/32/24608_2.png) [@joie](https://forum.babylonjs.com/u/joie)\
**Post date:** [February 21, 2023, 6:19am UTC](https://forum.babylonjs.com/t/transparent-material-appears-black-when-using-lightmap/38394/1 "2023-02-21T06:19:28Z")

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Hi there,

Continuing with the scene started [here](https://forum.babylonjs.com/t/rgbd-lightmap-banding/38375/14), I have a problem with the lightmap on transparency mapped materials, like the Rattan wood material of the chair:

 ![imagen](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/1/4/144b2fe801c918148e2bb4d006e60e0b115ca08f.jpeg)

The problem dissapears when deactivating the “use lightmap as shadowmap” feature, as you can see:

 ![imagen](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/c/4/c43081bbd665f0767dd9296a1578cc280f4c0a96.jpeg)

How can I fix that issue?

Thanks in advance!

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<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [February 21, 2023, 10:20am UTC](https://forum.babylonjs.com/t/transparent-material-appears-black-when-using-lightmap/38394/2 "2023-02-21T10:20:05Z")

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Could you provide a repro in the Playground? A transparent object is not treated any differently than an opaque object for lightmap purposes, so it may be a problem with the lightmap itself.

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<div class="post-metadata">

**Author:** ![joie](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/joie/32/24608_2.png) [@joie](https://forum.babylonjs.com/u/joie)\
**Post date:** [February 21, 2023, 6:32pm UTC](https://forum.babylonjs.com/t/transparent-material-appears-black-when-using-lightmap/38394/3 "2023-02-21T18:32:11Z")

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OMG you are right, those pieces are black in the lightmap!

For some reason, the lightmapper addon for Blender has troubles with transparency mapped shaders. I’ll tell developer about that finding.

Thanks!