# Simulating multiple scenes **URL:** \ **Category:** Questions\ **Created:** [June 2, 2025, 3:39pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785 "2025-06-02T15:39:27Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![bvaisman](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/bvaisman/32/20835_2.png) [@bvaisman](https://forum.babylonjs.com/u/bvaisman)\ **Post date:** [June 2, 2025, 3:39pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/1 "2025-06-02T15:39:27Z")
Hi everyone, I need to simulate multiple scenes but in a single one because I need to save / load my scene (stringify, LoadSceneAsync) and these functions only use a single scene : i can’t use the multiple scenes ([Babylon.js docs](https://doc.babylonjs.com/features/featuresDeepDive/scene/multiScenes/)). So I need to use multiple cameras, each of them showing only some meshes and hiding others… But : I’ve read that there are only 4 layers for the cameras ([Babylon.js docs](https://doc.babylonjs.com/features/featuresDeepDive/cameras/layerMasksAndMultiCam/)) and i do not know how many “scenes” i need. So I can’t use the camera layers either. Does anybody know how to do that ? Thanks, Boris ---
**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\ **Post date:** [June 2, 2025, 4:20pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/2 "2025-06-02T16:20:11Z")
There is no limitation to layerMask (it is a 32 bits number if you us 0x00000000 format so you have as much as you want :)) ---
**Author:** ![bvaisman](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/bvaisman/32/20835_2.png) [@bvaisman](https://forum.babylonjs.com/u/bvaisman)\ **Post date:** [June 2, 2025, 4:23pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/3 "2025-06-02T16:23:51Z")
Even for the cameras ? ---
**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\ **Post date:** [June 2, 2025, 4:35pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/4 "2025-06-02T16:35:47Z")
Yup, I’m not sure where did you get that feeling but the doc does not state there is a limit ---
**Author:** ![bvaisman](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/bvaisman/32/20835_2.png) [@bvaisman](https://forum.babylonjs.com/u/bvaisman)\ **Post date:** [June 2, 2025, 4:45pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/5 "2025-06-02T16:45:19Z")
It is probably because i did not underestand the doc here : > A `layerMask` is a number assigned to each mesh and camera. It is used at the bit level to indicate whether lights and cameras should shine-upon or show the mesh. The default value, 0x0FFFFFFF, will cause the mesh to be illuminated and shown by any stock light and camera. To determine if a mesh is seen by a camera, a [bitwise AND](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_AND) is performed and the result is compared to zero: _javascript_ ```auto mesh.layerMask & (camera.layerMask !== 0); ``` > The feature is used primarily when multiple cameras are active at the same time. If you wish to have a mesh that is always visible on the screen and pickable, e.g. a button, you might add a second camera and light to the scene to exclusively show and light it. > You’ll need the 2nd camera to ONLY see the button. The button should also only be visible once. > Notice that the default `layerMask` starts with the first 4 bits being 0, or off. If the 2nd camera and button were to both have a `layerMask` with one of the 4 values below, then the 2nd camera would only see the button: > - 0x10000000 > - 0x20000000 > - 0x40000000 > - 0x80000000 I will read it again. Thanks for your answer. ---
**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\ **Post date:** [June 2, 2025, 4:54pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/6 "2025-06-02T16:54:21Z")
Overall the idea is that a camera will render any mesh when `mesh.layerMask & (camera.layerMask !== 0)` is true so if camera.layerMask = 1 and mesh.layerMask = 1 then it will render 🙂 ---
**Author:** ![bvaisman](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/bvaisman/32/20835_2.png) [@bvaisman](https://forum.babylonjs.com/u/bvaisman)\ **Post date:** [June 4, 2025, 10:07am UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/7 "2025-06-04T10:07:53Z")
I’m really struggling with the masks but it’s very interesting. If I understand well, i mean there is a mistake in the docs. in this page ([Babylon.js docs](https://doc.babylonjs.com/features/featuresDeepDive/cameras/layerMasksAndMultiCam/)) it’s written : > mesh.layerMask & (camera.layerMask !== 0); And in this page ([Babylon.js docs](https://doc.babylonjs.com/features/featuresDeepDive/scene/layermask/)), it’s written : > So, for eg, if `camera.layerMask = 35` and `mesh.layerMask = 2` , `35 & 2 == 2 != 0` so the mesh is visible from this camera. So i mean the correct formula is : > (mesh.layerMask & camera.layerMask) !== 0. And if i’m right, there are only 32 combinations of masks which are excluding each others (if we are working with 32 bits). Am i right or do i understand anything ? Thanks for your answer. ---
**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\ **Post date:** [June 4, 2025, 3:37pm UTC](https://forum.babylonjs.com/t/simulating-multiple-scenes/58785/8 "2025-06-04T15:37:54Z")
You are totally right! The doc is wrong! I’ll fix it!