# Does having too many point lights suck all the energy out of other lights and the environment? **URL:** \ **Category:** Lighting and Rendering\ **Created:** [April 24, 2021, 5:51am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311 "2021-04-24T05:51:53Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![thinsoldier](https://blenderartists.org/user_avatar/blenderartists.org/thinsoldier/32/619644_2.png) [@thinsoldier](https://blenderartists.org/u/thinsoldier)\ **Post date:** [April 24, 2021, 5:51am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/1 "2021-04-24T05:51:53Z")
I downloaded a night scene that contained a lot of street lights. I want to make it daytime so I added Nishita Sky Texture. There seemed to be no shadows being cast by the sun in the sky texture. I turned off all the lights: ![2021-04-23 23_45_33](https://blenderartists.org/uploads/default/original/4X/e/8/d/e8d91c6852432a69c34c377a4e3257aeddfc1cad.jpeg) I see the shadows I expect from the sky texture’s sun I turn on 3 lights deep inside of a building at the far end of the street. Everything gets a little darker. ![2021-04-23 23_47_35](https://blenderartists.org/uploads/default/original/4X/2/b/0/2b0765c662aaad192dbf440ae065a8c5c86942a8.png) I turn on all lights that line the street and things get super dark: ![2021-04-23 23_49_17](https://blenderartists.org/uploads/default/original/4X/6/d/b/6db3262a459583410f55f2283e78813a80b2167d.jpeg) ![2021-04-23 23_49_59](https://blenderartists.org/uploads/default/original/4X/9/8/7/987209fd5f8b26adc4bc9a943e8ec5c821f5ca24.png) any idea what’s happening? This happens in 2.92 as well as the 3.0 branch with the new version of Cycles. I deleted all lights and recreated them from scratch. The problem still happens. ![point lights disabled](https://blenderartists.org/uploads/default/original/4X/f/a/3/fa3252773eb227db34c482f27ce3e9ddd13e1538.jpeg) ![point lights enabled](https://blenderartists.org/uploads/default/original/4X/8/a/a/8aa14f63d764326b274bc7a6027f1112b8f47aef.jpeg) ---
**Author:** ![lsscpp](https://blenderartists.org/user_avatar/blenderartists.org/lsscpp/32/3452_2.png) [@lsscpp](https://blenderartists.org/u/lsscpp)\ **Post date:** [April 24, 2021, 8:26am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/2 "2021-04-24T08:26:17Z")
Are you doing regular path tracing? I bet branched path tracing solves that situation. It’s quite a big limitation thou. I hope a robust solution will be behind the corner for cycles x ---
**Author:** ![thinsoldier](https://blenderartists.org/user_avatar/blenderartists.org/thinsoldier/32/619644_2.png) [@thinsoldier](https://blenderartists.org/u/thinsoldier)\ **Post date:** [April 24, 2021, 10:48am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/3 "2021-04-24T10:48:06Z")
Can you give more info about the actual limitation? I don’t understand what’s happening? ---
**Author:** ![lsscpp](https://blenderartists.org/user_avatar/blenderartists.org/lsscpp/32/3452_2.png) [@lsscpp](https://blenderartists.org/u/lsscpp)\ **Post date:** [April 24, 2021, 7:53pm UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/4 "2021-04-24T19:53:04Z")
I don’t know the technical side, but I also faced this problem. I think that branched path tracing can clear the issue since, by its design, for each sample the ray look for all lights in the scene, and not just a random one. ---
**Author:** ![CarlG](https://blenderartists.org/letter_avatar_proxy/v4/letter/c/aca169/32.png) [@CarlG](https://blenderartists.org/u/CarlG)\ **Post date:** [April 24, 2021, 8:09pm UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/5 "2021-04-24T20:09:06Z")
Keep in mind you can render out in different light passes and simply add the images together. For interior lights you can add a simple passthrough node group you can add as a dummy in world for easy access with the sun setup. ---
**Author:** ![Upliner](https://blenderartists.org/user_avatar/blenderartists.org/upliner/32/708965_2.png) [@Upliner](https://blenderartists.org/u/Upliner)\ **Post date:** [April 25, 2021, 10:55am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/6 "2021-04-25T10:55:19Z")
Have you tried disabling “Multiple Importance” on all of the point lights? It may result in more noisy image, but may solve problem with “light sucking”. ---
**Author:** ![thinsoldier](https://blenderartists.org/user_avatar/blenderartists.org/thinsoldier/32/619644_2.png) [@thinsoldier](https://blenderartists.org/u/thinsoldier)\ **Post date:** [April 25, 2021, 11:11am UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/7 "2021-04-25T11:11:54Z")
yes. no improvement. ---
**Author:** ![lsscpp](https://blenderartists.org/user_avatar/blenderartists.org/lsscpp/32/3452_2.png) [@lsscpp](https://blenderartists.org/u/lsscpp)\ **Post date:** [April 25, 2021, 9:30pm UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/8 "2021-04-25T21:30:45Z")
Ans what about using branched path tracing? ---
**Author:** ![thinsoldier](https://blenderartists.org/user_avatar/blenderartists.org/thinsoldier/32/619644_2.png) [@thinsoldier](https://blenderartists.org/u/thinsoldier)\ **Post date:** [April 25, 2021, 9:38pm UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/9 "2021-04-25T21:38:45Z")
yes branched path tracing works but only is available on CPU. The cpu in the laptop I’m using at the moment is slower than cpu in 7 year old macbook. No fun. ---
**Author:** ![lsscpp](https://blenderartists.org/user_avatar/blenderartists.org/lsscpp/32/3452_2.png) [@lsscpp](https://blenderartists.org/u/lsscpp)\ **Post date:** [April 25, 2021, 10:34pm UTC](https://blenderartists.org/t/does-having-too-many-point-lights-suck-all-the-energy-out-of-other-lights-and-the-environment/1300311/10 "2021-04-25T22:34:51Z")
Hopefully cycles x will tackle this once for all. They removing BPT in favor of regular path tracing and of course they know what they’re doing: I miss the technical part but something like sampling all light will be used, or at least the result will be like that. Actually I’m not sure how I know this…