Hey, we are trying to add support of multi-canvases in the Babylon.js editor but we are facing a problem. When using SSAO2 or Motion blur post-process (maybe other may generate this bug too), the rendering is broken: try to move the camera on the first canvas to see the problem. On line 79, try to …

Thanks for the repro! [image] julien-moreau: Also @Evgeni_Popov using this playground with SSAO2 ( https://playground.babylonjs.com/#2S2XU7#1 ) the result works as expected when not forcing geometry buffer renderer (using prepass I guess). It’s not really working, because the second viewport d…

I guess @Evgeni_Popov will be able to answer. cc @sebavan

Sounds like a limitation of multiview. I will see if I can find a quick fix.

I think it is connected with the active camera, because when adding motion blur, it is the camera that is setup for motion blur that becomes active in all views. And if you setup a camera in motion blur that is used as a camera with attachment control, then the behavior of all views breaks, because …

also i see the same behaviour using activeCameras and viewport

This is a limitation we currently have relying on PrePass / GeometryBuffer renderer. Let me check what is possible.

I do not think that there is an easy solution unfortunately and this might require to rely on the scene graph later. Currently I think you might need two copies of the scene :frowning: cc @Evgeni_Popov

Is there an easy way to basically create a new scene that is not just a copy but is synchronized with another one? If a mesh is added or moved in the first scene, do we need to manually synchronize it to take effect on the second scene? Thanks a lot :heart: for you help.

The multi-view feature is based on changing the active camera for each view and calling renderFrame, which is incompatible with frame graphs. We will have to think about supporting the multi-view feature with frame graphs, maybe by registering a graph with each view, instead of registering a camera? …

That’s interesting what you say @Evgeni_Popov . In that case, the bug we have maybe it can be fixed easily. It looks like the geometry buffer renderer or prepass renderer are not cleared properly or something like that. calling renderFrame with camera1 and SSAO2 then calling renderFrame with camera2 …

Multi-canvas and post-processes

Bugs

Soullnik July 22, 2025, 8:36am 6

I also tried to implement mutli view from this topic registerView question - #4 by nazmouse22, but see the same behavior

Topic		Replies	Views
Multi Canvas Picture in Picture Questions	14	757	November 28, 2023
Viewport issue when using PrepassRenderer Bugs	1	83	June 14, 2024
registerView question Questions	7	606	March 29, 2022
MotionBlur postprocess not working on a scene with multiple cameras Bugs	8	561	December 15, 2021
New feature: Multi canvases rendering Announcements	50	5233	February 19, 2020

Multi-canvas and post-processes

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