Chaos Corona Forum

Chaos Scatter => [Scatter] I need help! => Topic started by: filemon147 on 2018-06-22, 01:24:47

Title: trimming CoronaScatter?
Post by: filemon147 on 2018-06-22, 01:24:47
Hey, I guess it's been here already, but maybe im looking the wrong way.

I'm using CoronaScatter to scatter little patches of grass groups on a surface. The thing is - these patches are circular, and about 30cm in diameter.
The problem I've got is that they are being scattered with their 'gumballs' in center of the circle - which means they hang over the edge of surface.
I've added a photo below - vertex paint doesnt help, as this surface is already cut out to shape - therefore no need to control with vertex paint.
Title: Re: trimming CoronaScatter?
Post by: romullus on 2018-06-22, 11:41:33
Have you seen this topic: https://forum.corona-renderer.com/index.php?topic=9630.0 I think it has some solutions to your problem.
Title: Re: trimming CoronaScatter?
Post by: Frood on 2018-06-22, 13:51:24
You would need to cut the clump itself like ForestPro does with its Edge boundary checking mode. You can do something similar by using the amazing CoronaDistance map but you will have to extend every material used in the instanced objects (done that for a complete scene by script where I needed some kind of CoronaClipper for animation and it worked quite good).

Even more amazing, CoronaDistance works inside CoronaScatter instances. Just start interactive and move around the clipper objects. Unplug CoronaWire to get full clipping.


Good Luck

Edit: Just noticed that you can very simply define object based exclusions by plugging the distance map directly into the CoronaScatter objects distribution map slot - not what you need but this is a very quick and flexible way to define exclude areas. Would be interesting to see 3D-Map support for box scattering. So we would be able to cut holes of any shape into 3D scattered items :)


Title: Re: trimming CoronaScatter?
Post by: ChrisMyatt on 2019-03-14, 18:08:32
Frood's Method but at a Material level if you need it visually. With the grass you would need to do this to every grass material type.

Title: Re: trimming CoronaScatter?
Post by: sprayer on 2019-03-14, 18:17:30
With the grass you would need to do this to every grass material type.
And this script may help for that  =)
https://forum.corona-renderer.com/index.php?topic=12857.0
Title: Re: trimming CoronaScatter?
Post by: ChrisMyatt on 2019-03-14, 19:39:48
With the grass you would need to do this to every grass material type.
And this script may help for that  =)
https://forum.corona-renderer.com/index.php?topic=12857.0

Spot on Sprayer, i will have to have a dl of that