Flickering Grass and Game-Data Access Issues

[GetOutOfBox]

Try installing the tweak program "nHancer" and under the optimizations tab change the setting "Negative LOD Bias" from "Allow" to "Clamp". This will fix an issue with some video cards where the Negative LOD Bias is a large negative value.

 

http://i52.tinypic.com/2pr8co0.png

[Tenlethar]

Hi there,

 

i have been through more testing now - clamping the negative LOD Bias i did already before, but tried again now - but it didn't help. Uninstalling DirectX i have not tested yet.

 

But there is some other news:

 

Yesterday i decided to run some advanced Fallout 3 tests and guess what - while at first i thought the game runs fine, i found similar graphical glitches there!! I will record a video of that tomorrow.. but it apparently was the same thing happening! I got it on various spots in the game.

 

I also tried installing Oblivion on my other, older PC in my audio studio now - just for testing. I used a savegame i made on the newer computer. The glitch (grass flickering) was NOT there on the older machine. It runs a 4870, but its the same 4870 i used to test with on the new computer a few days back - and on the new computer, when using that 4870 i did get the glitches, so its probably not the card. It could be the drivers though (!?).

 

Now the weird part is that EVEN on the old machine i got the shadow-on-grass flickering. As mentioned above i didn't get the grass flickering there.

[Unclellama]

Did you ever solve this? :unsure:

 

I'm having exactly the same problem with grass flickering + 'shadows on grass' flickering a lot.

 

Running a Nvidia Geforce 470, AMD Phenix quad core 3.2 GHz.

 

I have a feeling this might have something to do with the 400 series graphics cards. They do something differently, and Oblivion takes issue with that. (I'm no hardware expert, though, and could just be talking out of my rear end).

 

The reason for this suspicion is that I use the Oblivion Graphics Extender, and the 'godrays' shader didn't work for those of us with 400 series graphics cards.

 

One of the team was nice enough to rewrite the shader so that it worked with the 400 series, and now I see the sun rays no problem. I still have the flickering grass issue, though, and had it from fresh install.

 

Just as you describe, it's usually worse with distant grass, although sometimes it happens up close. It really irritates the eye in wide-open areas!

[macdeffy]

I too have developed this problem, and I found a solution, though it may not help the OP. Maybe it will give someone insight. I was several hours into a new game, without issue, when my roommate decided he wanted to install oblivion. I had compiled my own lists of mods and tweaks, and wanted to test a fresh install to clear up unrelated minor bugs with my previous install. I installed oblivion on his computer with more or less the same mods and tweaks as my own. Everything ran fine, I copied over my savegame to test, which also worked fine, so I decided to copy over his Oblivion folder to my computer, since the modbase was a much smoother/faster/cleaner install.

 

However upon loading my savegame I was getting the flickering grass. No changes had been made to my oblivion.ini file, that I knew of, so I immediately loaded my old copy of oblivion, and IT TOO WAS FLICKERING! I came upon this post, and the symptoms were exactly the same, but I knew of the Negative LOD Clamp fix, and all the related known issues that supposedly caused this. I had already tweaked that before and had no problems. The game had worked before, and the only change being the oblivion folder itself, which would make one think it was a mod in the oblivion folder itself, and not the savegame and/or oblivion.ini file.

 

Rather then scratch my head, I knew I had one working system in the new install on my roommates computer. The first thing I did was copy my savegame and oblivion.ini over to his. Loaded up the game and FLICKERING! So it did appear to be a setting in my oblivion.ini file? I then copied the fresh oblivion.ini from his to mine, and NO FLICKERING!!! So I had narrowed it down to the oblivion.ini file at least. This makes things easier!

 

I then ran windiff to compare the two files, to see what the differences were. I tried changing every value that differed one by one until I came to fNearDistance=0.000. BINGO! Now normally this is set to 10. I had installed DeadlyReflex which recommends changing this to 0 to make certain animations display a little better, but it was optional. I tried other values besides 10, but it was the only value that did not cause the flickering. I tried variations of this setting, with other settings that differed, but it did not matter. As far as the ini file went, this was the only culprit, and no combination of values made a difference. The only strange thing is that I had been running this setting since I first installed without a problem, so what could have triggered this? and how can this relate to the OP's issue considering he has the problem on a vanilla install?

 

Initially I thought it might be shader related. I had enabled 3.0 shaders and copied shader019 to shader013, and one of my mods did patch this file, but after copying over an original shader file, and testing with hdr/bloom and without, it made no difference. I feel If I can find what settings allowed fneardistance=0 to work properly in the first place, then this may help the OP find a possible solution. I know that my roommates GTX260 was not detected properly by the oblivionlauncher when it first installed, so it was using shader004 with no hdr or bloom set. I did not change this at first because I knew I could change it later, so I did install all the mods. I do not know if somehow a file got modified someway and then when I ran his install on my computer, it then changed my INI somehow and that is why it no longer worked with my original copy with seemingly no changes. I have no copy of my original INI however, so it is moot. It's late and I must retire.

[MotoSxorpio]

To the OP:

 

You said on page four or five that the board you liked was because of its OC capability. Are you OCing during these testings? I have tried to replicate your problem, and I can by overclocking both the card and CPU of my machine.

[Datashocker]

Hi there. Judging from the date on your latest post, Tenlethar, you probably haven't been on these forums in a while. Regardless, I'm hoping someone else might see this thread and find us a fix.

I have this same problem. The flickering grass, as well as distant land flickering where it intersects with any mesh, such as a rock or the water plane.

I recorded a video of this a long time ago, and posted it on the nexus, but no one was able to help me.

Here it is;

 

Anyways, I have made a small amount of headway on this issue. As one of the above posters mentioned, setting the "fneardistance" variable in the INI file to the default value of 10 does greatly reduce the amount of flicker, however the flicker is still present if you look closely.

I have the same issue in Fallout 3, as well as New Vegas, although it is substantially more extreme in New Vegas, most likely due to the large amount of meshes intersecting with the distant LOD terrain.

 

So, if any of you could help find a solution to this, that would be greatly appreciated.

Edited August 22, 2011 by Datashocker

[Datashocker]

Bump

Trying to keep this on the first page.

 

No one has any input?

[HeyYou]

I get the same thing, to a lesser extent, on my machine..... I think it is just a factor of how the game renders LOD.....

[Datashocker]

It might be, but I've seen it running perfectly fine with no flickering at all on a different computer. So I'm pretty sure it's some software setting or hardware problem.

[HeyYou]

Try switching between HDR, and Bloom. See if that makes any difference.