Floating grass

Unity Engine
1

I just came across this ‘floating grass’ issue. Don’t know if it is a standard thing that is just more obvious on our current project, but I never noticed it before.

The grass billboards don’t seem to be following the terrain correctly. They mostly hover a bit over it (even on flat parts, but most visible on slopes), sometimes they are too low and intersect with the terrain. Not a big deal if you have a lush expanse of grass with lots of overlap, but a few isolated blades on a ridge look weird.

Is there any way to adjust this?
Thanks!

92370--3634--$floaty_grass_112.jpg

2

I have the same problem with trees.

Does the grass “ground” itself when you get close to it?

It seems when my trees switch from billboards to objects they “ground” themselves.

Sorry I have no solution for you.

—Josh

3

Thanks for the response, I am glad I am not the only one even if we don’t have a solution :wink:

Unlike trees, grass always uses images, there is no switch from billboard to geometry. But it does seem to be properly grounded when I turn off ‘billboarding’, so I guess it has something to do with the pivot point of billboards.

Unless there is a fix, I think I’ll stick to the ‘floating grass’ for now and try to work around the problematic areas.

cheers

4

This is a problem for me too. It must have to do with what unity considers the ground to be-- like, if it places the artwork with a sort of box type colliding algorithm, then the highest point where the box touches it is where it would stick. Maybe for these tricky spots, it’s better to manually insert the grass as individual billboards so that you can get it where you want…? But that’d be awful for huge levels… maybe turning off the billboard/face player feature would help?

Or, maybe there is a better way? For my situation, it’s really bad when you are walking upwards, and you can see the grass from below…

5

Can you move the pivot point up on the grass prefab?

I’ll try it on my trees and let you know if it works.

—Josh

6

http://forum.unity3d.com/viewtopic.php?t=13621

I had a similar problem and still no real answer… my problem was that the pivot point on billboard grass under the size of 1 seems to be offset, anything over that seemed to be ok, but that doesnt work for what i’m doing.

I duck taped a solution by havin a long texture that was mainly blank with my grass texture off center, its an ugly soultion but with no real answers its the best i could came up with.

Kinl

7

Hi Kinl,
yeah, that would make sense as I am using grass in the 0.2 to 1 range… I’ll have to try your clever workaround (a bit worried about performance), but I don’t think I have much time to tinker with this before the UA2008 deadline.

Did you submit a bug for this? Hopefully UT can fix it for the next release…
cheers

8

I havent submitted a bug (i’ve only just got to grips with doing that when its not a crash)

I’ll try to do it asap… tho if you do it too it gives us another chance of gettin it fixed :slight_smile:

9

I’ve been placing grass in my level. I use a layered photoshop file with an alpha. I just made sure that the grass layer was close to the bottom of the photoshop document. No floating grass.

I did notice the grass acts a little strange when it’s painted on geometry with extreme angles.

The grass texture looks like this.

—Best

97066--3769--$grass2_110.png

10

I’ve got the same problem. The pivot seems to be somewhere at the right bottom corner of the texture (or even outside of the texture?). So of course, if you turn on billboards, your object is moving a lot while walking from one side to another. Because of that in our project the grass looks good from one side, but grows on the street in some other points of view.

Changing sizes above 1 doesn’t affect this issue. Maybe, does somebody have a workaround?

11

I actually noticed this in a few places in the island demo too. I’ve never found a fix. It’s worse on steep hillsides.

12

Where did you guys get standing grass? I saw some in the island demo, but I couldn’t find it in the project view or asset folder.

13

Standard Assets.
Add it though the Terrain settings.

14

I’ve got the same problem, but i solve it in a strange way, just disable the render on the terrain gameObject then enable it again!! , that solve my issue but can’t know the reason!!