Author Topic: Chaos Scatter - Instances outside spline restrictions still there?  (Read 169 times)

2022-10-28, 12:15:59

d4l1

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Hi, hope you all doing fine! :)

I'm working with Chaos Scatter in Corona 9 (C4D 2023) and I try to use the Scatter for some small parts / thin stripes on my ground plane.
Because of the nice stuff the Scatter comes with, including the Include / Exclude with Splines and also the Edge Trimming I somehow hoped that this setup would be enough to scatter the plants, without having to cut out little islands out of my big ground plane to spawn the plants on. But it seems like - internally - Chaos Scatter deploys instances for the whole object which results in crashes if I'm overdoing the Instances / cm². Camera clipping is on, the viewport only shows me preview objects inside my spline but yeah - it crashes. If I use a way smaller ground object everything works fine. :)

Am I missing something there or is it a technical limitation I'm not aware of? For now it works like every other Scatter plugin I've tried - really hoped that I can get rid of that tedious work.

2022-10-28, 13:18:10
Reply #1

TomG

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The crash report would help, to see why it crashed. And the scene would also help. https://support.chaos.com/hc/en-us/articles/4648898278545-How-to-report-issues-C4D has info on where to find the minidump, and both scene and minidump can be sent in via https://support.chaos.com/requests/new
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2022-10-28, 13:48:15
Reply #2

romullus

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But it seems like - internally - Chaos Scatter deploys instances for the whole object which results in crashes if I'm overdoing the Instances / cm². Camera clipping is on, the viewport only shows me preview objects inside my spline but yeah - it crashes. If I use a way smaller ground object everything works fine. :)

That's right, the scatter indeed distributes instances on the whole area and then culls them down according to defined spline area and/or camera view frustum. It have to do this, otherwise on every slightest move of the camera, or change of area defining splines, it would have to redistribute instances and that would be really bad thing - imagine rendering camera flyby animation, where scattered trees, or grass would change their position on every frame.

As for the crashes, that should not happen even with very large number of scattered instances and you should report it as suggested by Tom.
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2022-10-28, 13:59:27
Reply #3

d4l1

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Ok! Thanks for your quick response. Just filled out the bug report form and included the project + bugreport stuff. I really hope I didn't forget something :)

2022-10-28, 14:01:48
Reply #4

d4l1

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But it seems like - internally - Chaos Scatter deploys instances for the whole object which results in crashes if I'm overdoing the Instances / cm². Camera clipping is on, the viewport only shows me preview objects inside my spline but yeah - it crashes. If I use a way smaller ground object everything works fine. :)

That's right, the scatter indeed distributes instances on the whole area and then culls them down according to defined spline area and/or camera view frustum. It have to do this, otherwise on every slightest move of the camera, or change of area defining splines, it would have to redistribute instances and that would be really bad thing - imagine rendering camera flyby animation, where scattered trees, or grass would change their position on every frame.

As for the crashes, that should not happen even with very large number of scattered instances and you should report it as suggested by Tom.

Ok, yes, sounds reasonable. Changing position every frame sounds even worse than my crashes :D

2022-10-28, 14:35:50
Reply #5

Beanzvision

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Hi there, I have checked your scene and it seems one (or more) of the plants is causing the crash when rendering close. I'm not sure which one or why but if replacing them, it renders ok. I do have your support ticket so we will look into it. For now, perhaps a process of elimination of plants to see which one is the trigger. I hope that helps. Attached is my test render.

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2022-10-28, 16:27:34
Reply #6

d4l1

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First: Thanks! Really appreciate the fast response to my problem.

I'm quite busy otherwise but will hopefully check the scene tonight when I've time or - if not - I'll be back again in a week. Then I'll take a look on each plant and maybe remove the bad one.
But I'll be back with the result tonight / in a week!

Thank you!

2022-11-07, 10:33:02
Reply #7

d4l1

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Ok! Back at work again.

I've checked the scene and tried to find the 'bad guy' within the group of plants, but it seems like there is none.
Sometimes it seems like I found the one object that causes the crash, but if I try a different variation of plants without the bad one, it still crashes sometimes. And if I re-add the bad one to a smaller amount of different plants it works fine again.

One thing I totally forgot to mention was the fact that I also tried to work with Edge Trimming - especially in that specific part of the scene it really helps because the plants should be a little bit bigger. For me it looks like removing all the Edge Trimming from the Opacity slots instantly solves the problem. After that I tried to remove all Edge Trimming from the Opacity slot and use a default Alpha Map to check if it happens because there is simply too much Opacity stuff happening if rendered that close, but the crash doesn't happen again. Looks like it has something to do with the Edge Trimming.

Next few steps included to find out, if there is a specific plant that causes the crash and it looks like that Majoran is causing troubles if it has Edge Trimming enabled AND is used combined with other plants. Solo Majoran plant with enabled Edge Trimming works fine, but if I add another plant to the Scatterer it crashes again. Adding all plants except Majoran (with Trimming enabled) works fine ... and adding Majoran with no Edge Trimming to the whole pack also works.

Sooo - lot of trial and error later: I'll have a look if it is enough if Majoran has no Edge Trimming enabled or if I remove that plant completely to be sure it doesn't crash later on ...
The mesh itself is quite thin and having the camera that close is nothing special I guess ... but for now I'm satifsfied. Don't know if this is now because of the mesh or if there is something 'buggy' with the Edge Trimming plugin and it would need a proper bug report?

But anyway: Thanks for the help!