# Volumetric Lightmap Sublevel Transform Fails

**URL:** <https://forums.unrealengine.com/t/volumetric-lightmap-sublevel-transform-fails/483399>\
**Category:** Rendering\
**Tags:** sublevel, Level-Streaming, unreal-engine, Lightmap, Lighting, procedural, question\
**Created:** [May 15, 2021, 12:15am UTC](https://forums.unrealengine.com/t/volumetric-lightmap-sublevel-transform-fails/483399 "2021-05-15T00:15:52Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Skunkmeister](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Skunkmeister](https://forums.unrealengine.com/u/Skunkmeister)\
**Post date:** [May 15, 2021, 12:15am UTC](https://forums.unrealengine.com/t/volumetric-lightmap-sublevel-transform-fails/483399/1 "2021-05-15T00:15:52Z")

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My team and I are attempting to create a procedural dungeon system. To preserve that sweet sweet UE4 lighting, we want to spawn sublevels with their lighting baked in.

At this time this seems largely impossible, because upon streaming sublevels, volumetric lightmaps do not copy the transformation of the newly created level, and only a single volumetric lightmap is instantiated in the environment at a time. This is prohibitive to attempts at high quality procedural environments, like a dungeon crawler composed of handmade rooms. See for yourself:

 ![338867-ue4editor-gnkfkx6t0h.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/b/a/b/baba1e91db044e429628ae1abcc172d0519d616d.jpeg)

I’ll add that I’m not alone. See [here][2] and [here][3]

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**Author:** ![JaroMast](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@JaroMast](https://forums.unrealengine.com/u/JaroMast)\
**Post date:** [January 29, 2023, 11:03am UTC](https://forums.unrealengine.com/t/volumetric-lightmap-sublevel-transform-fails/483399/2 "2023-01-29T11:03:24Z")

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Have you found a solution? Bump

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**Author:** ![Kettenotter](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/kettenotter/32/620822_2.png) [@Kettenotter](https://forums.unrealengine.com/u/Kettenotter)\
**Post date:** [June 9, 2023, 6:56am UTC](https://forums.unrealengine.com/t/volumetric-lightmap-sublevel-transform-fails/483399/3 "2023-06-09T06:56:17Z")

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Hey the only solution I can think of is this:

1. Stream in the current VLM for the room.
2. Transform all actors so that the current room is at 0,0,0 and aligns with its VLM.

Here is a workaround for the first part I wrote:

> [@Volumetric Lightmap Streaming Workaround - Multiple VLM - GPU Lightmass Memory Limit](https://forums.unrealengine.com/t/volumetric-lightmap-streaming-workaround-multiple-vlm-gpu-lightmass-memory-limit/746598):
>
> Guide for: Baking and Switching between multiple Volumetric Lightmaps Why? Per Sublevel baking is supported - but when you use volumetric lightmaps you have to bake everything at once - on larger worlds this will increase baking time or hit your memory limit. How? Unreal doesn’t support multiple VLMs (Volumetric Lightmaps) instead one global volumetric lightmap texture is set on Level load. But there are two interesting behaviors: It will use the VLM from the latest loaded Level when one is …

For the second part you just need to capture the relative transform of each actor/sublevel to the current room. Set the current room to 0,0,0 and then reapply the relative transform to each actor/sublevel.