ChaosScatter slowing down viewport playback even with "Previz Type" set to "None"

[Undersky]

We have an asset scene setup with scattering for the team to go and collect whatever scattering they need for the project. But when doing so, the viewport performance drops considerably even with no scatter display.

If I merge the objects separately into a new scene (first scatter meshes then ChaosScatter objects and lastly terrain mesh) there isn't any problem and I get a fps of around 150. But by importing them separately the connection between ChaosScatter objects and the terrain mesh is broken. So if I add the terrain in the ChaosScatter object (and still have the "Previz type" set to "None") the framerate drops to 23-25. If I delete the ChaosScatter objects the framerate is still around 23-25. If I then save the scene and open it again, the framerate is back up to 150.

3ds Max 2022
V-Ray 6 Hotfix 2

[vladimir_krastev]

Hi, thanks for posting. There are a few known issues about slow viewport and Chaos Scatter currently. I have a slight concern that your issue is something new though. Does it happen in every scene, even a new one with just lets say boxes for instances?

[Undersky]

Hi, thanks for posting. There are a few known issues about slow viewport and Chaos Scatter currently. I have a slight concern that your issue is something new though. Does it happen in every scene, even a new one with just lets say boxes for instances?

Our models for this project actually are very low detail and somewhat boxy, so they're not far off from regular boxes =) But yeah, I just tried it with boxes without material and it's the same thing. Removing the meshes from the "Instanced model objects" list restores the framerate again. In this specific case I have eight ChaosScatter objects.

[Undersky]

Disabling the ChaosScatter objects seems to solve it. Although you'll have to close the "Chaos Scatter Lister" window in order for it to speed up again.

[vladimir_krastev]

Hi it definitely sounds like a currently active issue that has been logged in our bug tracking system. I will add you tread to it and bump the priority.

[Undersky]

Hi it definitely sounds like a currently active issue that has been logged in our bug tracking system. I will add you tread to it and bump the priority.

Great, thanks!

[Undersky]

Just thought I'd update with how all this went down. It turned out that Chaosscatter is not ready for production. Major slowdown in scenes and sometimes not rendering the scattered objects on the farm. But it was mostly the slowdown that killed it for us. The solution half way into the project was to collapse everything into instances (tens of thousands sometimes) and doing the more detailed stuff (grass) with tyFlow instead. The slowdown seemed to stay until you restarted 3ds Max.

Some suggestions that could help is a way to better create "eco systems" within a single Chaosscatter object. The more Chaosscatters we had in the scene, the slower it got, but that was the only way to get some sort of clumping look of plants, instead of just randomly scattered. So if we could have some clumping control (look at Forest Pack) it would be great. It would also solve the problem with multiple Chaosscatter objects not being able to detect collision from eachother, potentially spawning intersecting geometry.

[JonasNöll]

Just thought I'd update with how all this went down. It turned out that Chaosscatter is not ready for production. Major slowdown in scenes and sometimes not rendering the scattered objects on the farm. But it was mostly the slowdown that killed it for us. The solution half way into the project was to collapse everything into instances (tens of thousands sometimes) and doing the more detailed stuff (grass) with tyFlow instead. The slowdown seemed to stay until you restarted 3ds Max.

Some suggestions that could help is a way to better create "eco systems" within a single Chaosscatter object. The more Chaosscatters we had in the scene, the slower it got, but that was the only way to get some sort of clumping look of plants, instead of just randomly scattered. So if we could have some clumping control (look at Forest Pack) it would be great. It would also solve the problem with multiple Chaosscatter objects not being able to detect collision from eachother, potentially spawning intersecting geometry.

I had the same issues. Especially the viewport slowdown is annoying. Doesn't matter if the ChaosScatter objects is hidden, set to box, pointcloud or anything. As soon as it's in the scene you can goodbye to realtime performance in the viewport during animations.
Haven't had any issues rendering on the farm though, that went fine.
The other thing is that the camera clipping is broke, so if you have motionblur enabled then your scatter objects will completely freak out and fly all over the place. So always have to disable camera clipping and always load all the instances in the scene. Not very performant but at least it works.
I prefer Chaosscatter for simpler setups where Forestpack tends to be more difficult to setup. From my experience it seems easier to setup initially with more predictable results while Forestpack is a bit more tedious with it's 500 submenues.
So for now i think its still necessary to have both, Chaosscatter and Forestpack. As Chaosscatter is integrated for free, I don't complain. Happy to have that. But I wouldn't purchase it as an additional plugin as of now.

[vladimir_krastev]

Hi JonasNöll have you tested with latest versions about the motion blur+camera clipping issue? We had that reported and fixed. It should work with latest versions of V-Ray 6.

[DougBowker]

This explains a lot. I have also been having issues around this because let's face it, in the short-term it's so much easier to grab the Cosmos browser tree/bushes/whatever scatter tools and throw down some foliage in a scene as opposed to Forest Pack Pro. Now ,knowing that each time another scatter is added, I will need to re-think this ASAP. Surely the Chaos Scatter is basically licensing the tools from iToo anyway, yes? There must be a (excuse the pun) a middle ground between the two sets of tools.

[JonasNöll]

Hi JonasNöll have you tested with latest versions about the motion blur+camera clipping issue? We had that reported and fixed. It should work with latest versions of V-Ray 6.

Hi, haven't tested it with the latest versions yet. I had this issue a few months back. So if that's fixed that great! Will check it out!

[vladimir_krastev]

Please do and share the results if you can.

[rowan_manns]

Hi,

I'm Rowan from the Chaos Corona and Scatter QA team. This post was brought to my attention, and I have a few questions which should hopefully enable us to look deeper into these issues and work on fixing them.

General Question:
Please can you state exactly which versions of Chaos Scatter and V-Ray you are using?

Viewport Performance:
Secondly, reproduction scenes are super useful for us. If you are able to send me over one of these scenes where the viewport performance is tanking then it would be great. You can upload it confidentially to me here: https://upload.chaos.com/d/qa_corona...a-renderer.com
I would appreciate some steps to reproduce the issues you are describing too.

Instances not appearing on render farm:
This, to me sounds like scatter was not correctly installed on those machines. I would recommend checking if it actually got installed there. We made some fixes to the installer in Scatter 2.4, which could explain your issue here.

Motion Blur + Camera clipping
Please test with the latest V-Ray + Scatter as vladimir_krastev suggested. If the issue is still present we can look into it.

DougBowker - Scatter is developed purely by Chaos.

Thanks for the feedback!

Rowan

(Internal ID=989621917)

[tjconnors]

Hello,

I'm having the same issue with the viewport performance being super slow when trying to change frames with scatter objects. The work around of disabling them in the lister does fix the issue but that is a really slow process. I just tired the vray update from today and I still have really slow performance even hidden. And thoughts on why it could be so slow? Everything is proxy objects. Scatter display is really low.

Running max 2024
Vray 6.20.06 build 00000

Cheers

[vladimir_krastev]

Hi, the issue with slow viewport performance compared to Forest Pack (internal tracker SCATTER-91) has made a lot of progress. We still do not have a fix and work continues. We can not share any timeline information right now.