# Building lighting taking too long

**URL:** <https://forums.unrealengine.com/t/building-lighting-taking-too-long/486274>\
**Category:** Rendering\
**Tags:** skylight, lighting-build, unreal-engine, Lighting, question\
**Created:** [July 19, 2021, 6:07am UTC](https://forums.unrealengine.com/t/building-lighting-taking-too-long/486274 "2021-07-19T06:07:23Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![anonymous\_user\_d3ea292c](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_d3ea292c](https://forums.unrealengine.com/u/anonymous_user_d3ea292c)\
**Post date:** [July 19, 2021, 6:07am UTC](https://forums.unrealengine.com/t/building-lighting-taking-too-long/486274/1 "2021-07-19T06:07:23Z")

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I have imported a 3ds max model into UE4 ( 4.20) and when i tried to build the lighting it takes like forever by stucking at 0 percent. at the begining i got an error that i solved it by adding " lightmass Importance Volum" as a box around the whole seen. I tried to change then name of the folder save and didnt work. I looked at Swarm agent and here is the weird thing :

brown lines " Cashing irradiance photons (9202.4 seconds)" followed by Black lines " SkyLight Radisoity ( 1853 and counting).

is there anything wrong I have done here ? I would appreciate it if somone had faced the same thing before .

PS : CPU usage is 100 percent ( Core-i7) with 32G of Ram.