# How to detect overlap on UE4 grass system...
**URL:** https://qa.fmod.com/t/how-to-detect-overlap-on-ue4-grass-system/13312
**Category:** Unreal Engine
**Created:** [July 25, 2017, 10:20pm UTC](https://qa.fmod.com/t/how-to-detect-overlap-on-ue4-grass-system/13312 "2017-07-25T22:20:42Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@SonikSky](https://qa.fmod.com/u/SonikSky)
#### Post date: [July 25, 2017, 10:20pm UTC](https://qa.fmod.com/t/how-to-detect-overlap-on-ue4-grass-system/13312/1 "2017-07-25T22:20:42Z")
Hi, currently have my Physical Materials in UE4 assigned to the meshes of the grass used in the grass system. My Physical Materials call a data table that directs FMOD on what to play…
I’m using this for the landscape layers to create Foley audio when you drive over it. But I can’t seem to get my pawn to detect when I overlap the foliage.
Ideally, I’d like to drive over or through a big bush and trigger my FMOD audio event in the PM Data Table as well as any other particles effects in the table.
I know if we made these manually with trigger boxes, it could be done, but there has to be a more efficient way to just detect when you’re encountered an object in the grass system wit ha pawn, is there something I’m missing?
Right now, I’m currently using a ray-trace to determine the physical material. This works just fine on the terrain layers or on the collision with objects that have geometry on them. Such as speedtree…
Is there a way to know when the pawn overlaps the grass foliage system?
Any help or directions to be pointed in would be helpful. Thank you.
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### Author:  [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)
#### Post date: [July 28, 2017, 12:52am UTC](https://qa.fmod.com/t/how-to-detect-overlap-on-ue4-grass-system/13312/2 "2017-07-28T00:52:44Z")
> [@](#):
>
> Hi, currently have my Physical Materials in UE4 assigned to the meshes of the grass used in the grass system. My Physical Materials call a data table that directs FMOD on what to play…
>
> I’m using this for the landscape layers to create Foley audio when you drive over it. But I can’t seem to get my pawn to detect when I overlap the foliage.
>
> Ideally, I’d like to drive over or through a big bush and trigger my FMOD audio event in the PM Data Table as well as any other particles effects in the table.
>
> I know if we made these manually with trigger boxes, it could be done, but there has to be a more efficient way to just detect when you’re encountered an object in the grass system wit ha pawn, is there something I’m missing?
>
> Right now, I’m currently using a ray-trace to determine the physical material. This works just fine on the terrain layers or on the collision with objects that have geometry on them. Such as speedtree…
>
> Is there a way to know when the pawn overlaps the grass foliage system?
> Any help or directions to be pointed in would be helpful. Thank you.
You may have more luck asking this on a general UE4 forum rather than here.
I’ll leave this question here in case any other users have any ideas.
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### Author:  [@SonikSky](https://qa.fmod.com/u/SonikSky)
#### Post date: [July 28, 2017, 1:16am UTC](https://qa.fmod.com/t/how-to-detect-overlap-on-ue4-grass-system/13312/3 "2017-07-28T01:16:17Z")
Hey there… Thanks… I did ask on UDN on this one as well. I think I’m close to figuring it out… Getting the mesh’s themselves to generate volume boxes upon spawn… instead of having to manually place each one. Looking into this now…