# Build Lighting 'resets' lightmap changes in StaticMesh Editor **URL:** \ **Category:** Rendering\ **Tags:** unreal-engine, bsp, Lighting, question\ **Created:** [November 6, 2015, 12:38pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652 "2015-11-06T12:38:40Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Dead\_Knight](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Dead\_Knight](https://forums.unrealengine.com/u/Dead_Knight)\ **Post date:** [November 6, 2015, 12:38pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/1 "2015-11-06T12:38:40Z")
Hi everyone, I have a problem (or maybe do something wrong) with common error ‘Object has wrapping UVs’. First of all I create sketch-level from BSP-brushes, set textures, and then convert BSP to StaticMeshes. And got this problem (‘Object has wrapping UVs’). Ok, I google for solution for this problem, and found it. After changing lightmap index from 0 to 1 → Apply Changes → Save Mesh I see this: ![65795-problem.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/d/f/cdfcd10f310c17cbd6ad4f5d25dd4323b981ace4.jpeg) Woohoo, that’s what I need! Just rebuild lighting… I press ‘Build All’ wait, and… WHAT??? I see this: ![65796-problem2.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/1/e/5/1e528b7124cb12027550f0d82a695304ce509b9a.jpeg) I open every mesh in MeshEditor and all settings was correct: ![65797-problem3.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/c/5/0/c50bd4e3f5c9735fd3b0e0d47583431656598a44.jpeg) I try change ‘Destination Lightmap Index’ to 0 or 2, but this changes don’t affect on final relsult (problem2.png). This is bug or I do something wrong? ---
**Author:** ![anonymous\_user\_2ed5b4c7](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_2ed5b4c7](https://forums.unrealengine.com/u/anonymous_user_2ed5b4c7)\ **Post date:** [November 6, 2015, 1:22pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/2 "2015-11-06T13:22:59Z")
Hi! 1. **Source Lightmap** - always must be 0. Because this main **Color** channel. Lightmap always applied to this channel. 2. **Destination Lightmap Index** - always must be 1. Because this is channel only for Lightmap. And always used for build light. ![65789-lihgtmap.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/e/a/2eace09837cf382887701f6abc9097d76347ec71.jpeg) ---
**Author:** ![Dead\_Knight](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Dead\_Knight](https://forums.unrealengine.com/u/Dead_Knight)\ **Post date:** [November 6, 2015, 1:29pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/3 "2015-11-06T13:29:51Z")
Thank you for your answer, but as I see in Wiki: > **[A new, community-hosted Unreal Engine Wiki](https://forums.unrealengine.com/t/a-new-community-hosted-unreal-engine-wiki/141494)** > > After over a year in maintenance mode, the official Unreal Engine Wiki is now permanently offline. These resources now live on a new community-run Unreal Engine Community Wiki — ue4community.wiki! You will be able to find content from the official... changing ‘Source ligthmap index’ it’s correct way to fix ‘Overlapping UVs’. ---
**Author:** ![anonymous\_user\_2ed5b4c7](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_2ed5b4c7](https://forums.unrealengine.com/u/anonymous_user_2ed5b4c7)\ **Post date:** [November 6, 2015, 1:42pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/4 "2015-11-06T13:42:04Z")
Lightmap always use UV 1 (secondary UV channel). UE4 always read info from Lightmaps from UV1. ‘Overlapping UVs’ appear if secondary channel empty or your mesh have only one first UV channel. ---
**Author:** ![Dead\_Knight](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Dead\_Knight](https://forums.unrealengine.com/u/Dead_Knight)\ **Post date:** [November 6, 2015, 2:30pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/5 "2015-11-06T14:30:06Z")
I set all values as you advised, and have this in StaticMesh Editor: - UV Channel 0 (wrong) ![65801-problem4.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/4/5/2/452b31aff1592578491e4c5cdf34ca0c7931c1d2.jpeg) - UV Channel 1 (seems fine) ![65802-problem6.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/1/3/7/1373ee94d295bb2e7a04a3322838c425b14eebe7.jpeg) And in editor this: ![65803-problem5.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/9/1/5/915241b8215df76524399fc4ab66afd3093783cb.jpeg) As in initial situation it’s BSP converted to Static Mesh. And in all cases any changes in StaticMesh Editor makes scene looks good, but only before pressing ‘Build’ button. ---
**Author:** ![anonymous\_user\_2ed5b4c7](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_2ed5b4c7](https://forums.unrealengine.com/u/anonymous_user_2ed5b4c7)\ **Post date:** [November 6, 2015, 2:40pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/6 "2015-11-06T14:40:59Z")
Converting BSP in static mesh have bug. You need open mesh editor and input any value in **Light Map Resolution**. This parameter located in **Static Mesh Setting** in **Details**. But you changed **Min Lightmap Resolution** this is no right. In my previous picture **Light Map Resolution** marked with number 3. ---
**Author:** ![Dead\_Knight](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Dead\_Knight](https://forums.unrealengine.com/u/Dead_Knight)\ **Post date:** [November 6, 2015, 2:54pm UTC](https://forums.unrealengine.com/t/build-lighting-resets-lightmap-changes-in-staticmesh-editor/337652/7 "2015-11-06T14:54:13Z")
Ok, as I understand my problem was be in my wish: Create Laaarge Mesh from BSP (it’s works wrong in UE4 =( ). I provide some tests in small objects and all works fine.