But it’s about distance from the spline, right?
So if I scatter on a square that’s 5000x5000mm and a bordering closed spline around it as an exclude set to 100/150mm the WHOLE scatter shouldn’t be disabled…
I think the proof is that if I break that same spline even by a tiny amount so it’s not closed, the scatter works as expected…
To me it sounds like the current behavior is expected, but maybe I am missing something. Could you share some screenshots / renders showing what exactly you are doing and why? That would greatly help us.
Other than that - maybe you can use the Corona Slicer Material for edge trimming? https://support.chaos.com/hc/en-us/articles/4956761514897-How-to-use-the-Corona-Slicer-Material
Sounds like this is by design, you need to be able to use a closed spline while still being able to use distance on the outside of the spline. The solution would be to break the spline, unless I’m missing something. 
That’s right, but the thing is, that near/far feathering radiates outside of closed spline, not inside, so if your spline is exactly bordering your distribution mesh, then no matter what you’ll do, it will always exclude everything.
As for the splitting the spline - as soon as you do that, there’s no longer an inside or outside and inclusion/exclusion will propagate from the spline in all directions.
So to me it still sounds like expected behavior, but if we can make our users’ lives easier, then why not?
I would still appreciate taking a look at what exactly the use case is so that we could report it to the devs. Thanks!
Another option is contacting us about this at https://support.chaos.com/hc/en-us/requests/new
Maybe you could do that near and far would take negative values as well, then user could choose in which direction to extend inclusion exclusion area. The only downside to this, is that negative values would make no sense with open splines.
Ok,
Thanks for all the input.
I guess the main takeaway here, for me, and probably other users, is that the spline include/exclude works differently if it’s closed or not. This is handy to know; If it’s closed, it excludes everything inside the spline, but if it’s open it excludes in a feather in both directions of the spline.
I think this double situational/conditional use is a bit confusing, personally, but can live with it
I guess the best case use of the closed spline is if the user wants to make ‘islands’ of no/only scatter. Understandable and useful.
Screenshots attached to show my 3 test findings. I no longer have a particular beef with the workflow, but perhaps other users can chime in?
As for the clipping material for clean grass edge surfaces… ugh, I don’t think this is a great scenario either. When using Corona scatter my previous best option was to use a shelled version of the scatter surface to act as a distance object for the opacity of the grass. This new suggested workflow isn’t much of an improvement - I still have to use a separate object. If I edit the scatter surface this breaks the shelled version of it (I know, I know, it can be a referenced instance, but this isn’t always clean/possible).
Is there a better workflow I’m unaware of for clean grass edges?
Thanks again.
Or some sort of tick box ‘act as closed island spline’ or something like that, which is only active when using a closed spline. Sorry to be suggesting adding complexity!
Yes, thanks. I mentioned this earlier
Random idea:
I think 3ds Max does not allow any out of the box way of adjusting the normals of a spline (e.g. if you extrude it along normals - there is no way to specify in which direction it should extrude - this is predefined depending on which viewport you created the spline in). Maybe “flipping normals” of a spline would work here? But how to do it is an open question.
Unfortunately I am not aware of any. We should do something about it. We already have this logged but thank you. 
Perhaps, just a little bit of friendly UI; when the user selects a spline as the object to scatter on, ChaosScatter could detect this and automatically set the scatter type to ‘on spline’?
Food for thought
Thanks
Hi,
Another query/request.
When I use the near/far includes splines on a scatter across a surface the number of scattered items is kind of confusing/messed up.
I understand the way the scatter works it takes as sample of surface and divides it up into x number of points to place items on. So this might be a very unreasonable ask:
But if I have a big surface (say a football field) and I want to scatter an object in a small inclusion area I must make the number very very big to ensure the inclusion area is filled. So I must enter say 100,000 items, but only say 5,000 will be scattered.
If I was scattering on a surface the size of the inclusion area (but not using any inclusion spline) and I set this scatter count to 5,000, it would scatter 5,000 pieces.
Is it possible to somehow get these numbers to be somewhat more controllable/predictable?
I haven’t done the best job here explaining myself, so hopefully it’s understood? Cheers!
I think it’s done this way to prevent scattered instances from randomly jumping when the user edits a spline. I’d recommend to switch from fixed number of instances to instances per area - not only you won’t need to enter very big numbers, but you also will be sure that you will get consistent results even if you drastically resize scattered surface. Personally i very rarely define total number of instances, because defining density is so much more convenient.
Hi,
Splines can be both linear objects and surfaces to scatter on. It is better that user decides which type of scattering should happen instead of auto-detecting but then changing.
The suggestion maybe the case for closed spline. But this can lead to another issue - splines, open or closed, can be made renderable and they become spline controled surfaces and in that case scatter cannot be sure what exact scattering is needed.
And this is actually a great feature. Because…
you can make the spline - open, closed, doesn’t matter - renderable, probably only in viewport and not in render.
And you will get what you need. You get double control - the physical size of the renderable spline plus the near and far from scatter parameters.
Hope this helps.
Thanks,
Aram
I hope displacement follow will be added to this scatter and clusters as well.
Make sure to cast your vote here: https://forum.corona-renderer.com/ The most wanted Chaos Scatter feature? ;]
Thank you, already done! Fingers are crossed!
I’m using Chaos Scatter to distribute trees on a 1800x1800m terrain surface. I have two scatter types, one for deciduous trees and one for pine trees. The two types are scattered on the same terrain, but driven by a black/white map that defines where the trees should grow according to how high up they are. I also have multiple splines set up to exclude scattering in some places.
My problem is that the scene has become incredibly slow, selecting the terrain or scatter objects and making adjustments takes so long that it’s impossible to work with. Finding it hard to work if I have to disable the scatters every time I need to make a change, and simply selecting them and disabling takes a long time. Also, I’m planning on scattering other vegetation like shrubs and grass on the same terrain, but it looks like this isn’t going to be possible using this technique.
I think the mask is slowing things down a bit, but the spline excludes slows even more.
Disabling the spline excludes in the list doesn’t help the performance, but deleting them eliminates the issue.
Is this to be expected using spline include/exclude, or is this a bug?
