Author Topic: Chaos Scatter Edge Trimming Playground!  (Read 3995 times)

2022-09-30, 14:38:39

maru

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Corona 9 RC1 comes with a new Chaos Scatter Edge Trimming feature!

Where to find it?
It's a new ChaosScatterEdgeTrimming map you can find in the material editor under the Chaos Scatter category.

How to use it?
You need to plug your Edge Trimming map into the opacity slot of the material of the object that you are scattering (in case of multiple objects - you need to plug this map into the opacity slot of every material used). If any part of the instance (any mesh element) falls outside of the area specified by the scatter, this part will be invisible. This area area can be specified using:
- The distribute-on target object itself (in case of scattering on a plane object, any instance part outside of the plane object will be invisible)
- Include splines (any instance part outside of the include spline will be invisible)
- Exclude splines (any instance part inside the include spline will be invisible)
There is no need to enable any special options in the Chaos Scatter object itself.

Where is this useful?
- Grass lawns - in case of using large grass clumps, no grass blades will be growing outside of the defined area (defined by the distribute-on object or by include/exclude splines)
- Carpets - in case of using large clumps of strands, no strands will be placed outside of the carpet area
- Pebbles, rocks, bark chippings, or any other objects which you need to distribute within some specific boundary and make sure no instances stick outside of that boundary.

What are the limitations?
- This feature comes with a certain precision. In case of distributing a model consisting of a lot of elements (think 10 000 elements or more), it would be too slow to check the position of each one of them. This means that trimming works best with models consisting of as few elements as possible, but at the same time, this limitation should not be a problem in usual scattering scenarios (scattering grass, trees, rocks, etc).
- When the distribute-on object is smaller than the model object itself, some issues may appear where the instances would stick outside of the expected area. The solution in this case is to make the scattered instances smaller. This also should not be a problem in usual use cases, because in practice it would mean having a smaller grass lawn area than a single grass patch.
- Currently, you need to manually (or using a script) connect the Edge Trimming map to the opacity slots of each of the materials you are using for your scattered instances. This can be challenging, especially in case of scattering models with many different materials. We are planning to improve this workflow.

Edge Trimming on:


Edge Trimming off:


« Last Edit: 2022-09-30, 20:20:35 by maru »
Marcin Miodek | chaos-corona.com
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2022-09-30, 20:00:06
Reply #1

aaouviz

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"Added new ChaosScatterEdgeTrimming map (under Chaos Scatter category). Can be plugged into opacity slot of model object's material to perform trimming of its whole individual mesh elements (e.g. grass blades in grass patches) for each instance alongside Include/Exclude splines and target object's boundaries"

I cannot for the life of me, get this to work... I have the ChaosScatterEdgeTrimming map plugged in to the material for the scatter object (do I need to plug anything into that, for it to work?). It just.does.not.work. I have Scatter build Sept 29 (RC1) installed. I can see the texture node, obviously, but no additional settings in the Scatter modifier list/settings?
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2022-09-30, 20:21:04
Reply #2

maru

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"Added new ChaosScatterEdgeTrimming map (under Chaos Scatter category). Can be plugged into opacity slot of model object's material to perform trimming of its whole individual mesh elements (e.g. grass blades in grass patches) for each instance alongside Include/Exclude splines and target object's boundaries"

I cannot for the life of me, get this to work... I have the ChaosScatterEdgeTrimming map plugged in to the material for the scatter object (do I need to plug anything into that, for it to work?). It just.does.not.work. I have Scatter build Sept 29 (RC1) installed. I can see the texture node, obviously, but no additional settings in the Scatter modifier list/settings?

Maybe the attached image helps?
Also: https://forum.corona-renderer.com/index.php?topic=37994.0
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us

2022-09-30, 20:24:19
Reply #3

PROH

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Haven't tried it yet. But it sounds extremely cumbersome to make this work. Imagine several objects with a multimaterial each.
That's not userfreindly.

2022-09-30, 20:25:48
Reply #4

aaouviz

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Haven't tried it yet. But it sounds extremely cumbersome to make this work. Imagine several objects with a multimaterial each.
That's not userfreindly.

Agreed - it's a nightmare with ForestPackPro. I was really hoping Corona would be able to make an improvement on this, very disappointed
Nicolas Pratt
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2022-09-30, 21:58:33
Reply #5

maru

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Haven't tried it yet. But it sounds extremely cumbersome to make this work. Imagine several objects with a multimaterial each.
That's not userfreindly.

Agreed - it's a nightmare with ForestPackPro. I was really hoping Corona would be able to make an improvement on this, very disappointed

From the playground thread:
Quote

Currently, you need to manually (or using a script) connect the Edge Trimming map to the opacity slots of each of the materials you are using for your scattered instances. This can be challenging, especially in case of scattering models with many different materials. We are planning to improve this workflow.
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us

2022-09-30, 23:31:44
Reply #6

romullus

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I think simple "trim edges" checkbox in the scatter object, would make more sense - Corona could add edge trimming texmap to the opacity slot internally at render time for user convenience. I did quick test with just 4 materials and already it was quite a chore to plug/unplug edge trimming map several times in a row. If you want to use the same asset in multiple scatters with and without edge trimming, you would need to duplicate their materials and that would quickly turn in to mess.

On the positive side, i was pretty pleased to find that the new feature does not slow down render very much, i was expecting worse.
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2022-10-01, 03:24:57
Reply #7

gentlestev

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can't find this chaos scatter edge trimming map on the chaos category of the material editor. remember i followed d exact steps in installing and running the daily build. any help

2022-10-01, 09:42:00
Reply #8

maru

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can't find this chaos scatter edge trimming map on the chaos category of the material editor. remember i followed d exact steps in installing and running the daily build. any help

You need to install Corona 9 RC1 - https://forum.corona-renderer.com/index.php?topic=36810.msg203961#msg203961

And then you should see it in the material editor:
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us

2022-10-01, 11:46:08
Reply #9

LorenzoS

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Hi all,
 i cann't reproduce the edge trimming effect, when i apply the ChaissScatterEdgeTrimmg map to the opacity slot of material, the slice effect is shown on all instances.

2022-10-01, 12:05:57
Reply #10

romullus

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Can you show your setup and the result that you get? There shouldn't be any "slice effect" - edge trimming is removing whole mesh elements that falls outside of scattered area.
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2022-10-01, 13:02:22
Reply #11

aaouviz

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Can you show your setup and the result that you get? There shouldn't be any "slice effect" - edge trimming is removing whole mesh elements that falls outside of scattered area.

Are you sure about this? It wouldn't be trimming then? It'd be more like removal.

But in any case... definitely 100% not working at all for me, tried for hours last night. I feel something is wrong with installation... I installed RC1 and scatter didn't update. I had to manually install scatter from unpacking the files and I'm sure I didn't do it right... or else it'd be working for me, right? (FYI in the info tab of scatter it says it is RC1 scatter from 29th Sept installed)
Nicolas Pratt
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2022-10-01, 14:17:09
Reply #12

romullus

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Are you sure about this? It wouldn't be trimming then? It'd be more like removal.

Can't speak for the others, but that's exactly how i want this feature to behave. If i'd want to slice geometry exactly and precisely along the edges, i could use Corona slice instead.

As for the installation, i had no issues at all - installed RC1 build and everything worked. Maybe there's some issue with multi-loader setup, like it was the case recently? OTOH, if you already tried unpack method and it still doesn't work, then i have no clue how to help, other then suggest to contact the support.
I'm not Corona Team member. Everything i say, is my personal opinion only.
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2022-10-01, 14:26:54
Reply #13

LorenzoS

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Can you show your setup and the result that you get? There shouldn't be any "slice effect" - edge trimming is removing whole mesh elements that falls outside of scattered area.

Works with grass downloaded from cosmos, but not with geometry create by myself (cube).

2022-10-01, 14:34:29
Reply #14

LorenzoS

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Can you show your setup and the result that you get? There shouldn't be any "slice effect" - edge trimming is removing whole mesh elements that falls outside of scattered area.

with checker applied