[Info] Specific Type Of FPS Drop

[AlizarinCrimson]

What This Is About:

A specific type of FPS stuttering/drop. What causes it. And how to fix it.

 

The Symptom:

A sudden and inexplicable fps drop that cannot be fixed by opening the console and typing tlb and that only occurs when looking in a specific direction.

 

 

What Causes Is:

This is caused by a bad nif file.

 

According to Kivan:

"It was (or seems to be) the early PyFFI NIFOptimize spell. I used it on all the NIFs in 3.0.0 and onwards. On recent PyFFI releases, it now shapifies NiTriStrips blocks with an average strip length less than 10. The old one strippified everything and on some meshes with very many very small strips this causes FPS loss."

 

[**This was written in relation to v3.0 and 3.1 of the UOP causing just this kind of fps drop. I am not entirely sure on it's meaning perse (I haven't got around to exploring what NifStrips actually are in pure modelling terms) ... however, v3.2 of UOP has halted all of those FPS drops that were related to it's fixed meshes.]

 

All in all I think this can be said: some meshes released by modellers are not friendly in the optimized sense of things. (See the end of this post for known meshes/mods that will cause and this fps drop.)

 

How To Fix:

• Remove the mod/mesh; if it's a replacer use the stock mesh instead.
  
• Try PyFFI-ing it.
  1. Get PyFFI
     
  2. Install
     
  3. Right Click on the mesh and choose Optimize With PyFFI
     

Current Known Mods That Cause This [DATE: 5 September 2008]

[b]Mod Name			Mesh				Known Fix[/b]
UOP v3 and 3.1			All				Download v3.2 or PyFFI
PAF's Boot Replacer		Iron Boots			No
			Dwarven Boots			No
Tona's Underwear		All				No
Hentai Lovley Suits		All				No
Hentai Uniform			All				No
Apachii Goddess Store		Platform Boots (Both meshes)*	No
Harvest Containers		XMSharvestLowerChest02LoFi.nif	PyFFI currently fails on it
			Stone (Vampire) Coffin		No		

 

*The boots that are part of the Bast Armor are fine. The separate boots are not.

 

Side Notes:

• First and foremost: any mods listed here are in no way be judged for quality or anything else. I am merely creating a list of mods that can/will cause fps loss. In fact, since I've downloaded them it should be obvious that, in fact, I like the mod... :P
  
• Second: You might be wondering how could this be? How could something like this go unnoticed for so long. This guy must crazy! In fact, it makes perfect sense that it has gone unnoticed. The drop is only of about 5 to 8 frames*. And if you're averaging at least 24 or so then a drop of 5 or a bit more while noticeable is nothing worth batting an eyelid at in Oblivion. However, if like me and you're running oblivion on a subpar system then those FPS hits can be incredible. Two examples:
  1. UOP Goblin Shaman Staff: FPS when looking at: less than 1 frame per second. Drop of over 20!.
     
  2. Paf's Dwarven Boots: FPS while looking at it: 10. Drops of about 5 or 6
     

  *Alright I'm being judicious, the drop can be freakin' massive.

  As such this while in some ways is specifically aimed at low performance people should also help those that are on those shiny high end monsters.

  [*] And finally: This is not a cause of CDTs.

Alright, hopefully this is helpful and informative. The next post I'm going to reserve for posting a deeper explanation on what is actually causing this, as soon as I learn what that is exactly. :)

 

Cheers, and now go and enjoy this wonderful game and all the fantastic mods out there!

 

P.s. Feel free to post explanations of this, or mods that you think might be causing this and if PyFFI-ing it helps. I'll try and test mods that are posted. But in general if tlb does not cause the fps to increase you have faulty mesh on your hands.

 

P.p.s. The great thing about clothing that causes this is that your system should hang when you equip it and rotating your character will not be as smooth as it should be. (You'll also get mouse lag.) Why's that good? Cause it's damned easy to tell. Much easier than say one rock mesh out of 60 on screen.

[AlizarinCrimson]

SPECIAL NOTE: the current release of PyFFI will fail on Harvest [Containers] meshes however, if you can get your hands on v1.0.1 it will work and will fix the fps hit caused by these meshes

 

 

This Post will be used to list mods and mesh that cause this:

 

Meshes [Date: 5 September 2008]

[b]Mesh					Directory				Mod[/b]
boots.nif 				[meshes/armor/iron/boot.nif]		Paf's Boot Replacer
boots.nif				[meshes/armor/dwarven/boot.nif		Paf's Boot Replacer
XMSharvestLowerChest02LoFi.nif		Harvest.bsa				
stahlgleve.nif				[meshes/weapons/Stangenwaffen]

 

Notes:

PyFFI fails on XMSharvestLowerChest02LoFi.nif (v1.0.1 of PyFFI works)

PyFFI fails on stahlgleve.nif (v1.0.1 of PyFFI works v 1.0.0 will work as well)

 

Mods That Have Meshes That Cause this [Date: 5 September 2008]

UOP v3 and 3.1

Paf's Boot Replacer

Tona's Underwear

Hentai Lovely Suits

Apachii Goddess Store

Harvest Containers

Oscuro's Oblivion Overhaul

 

[NOTE: I'll get to making the mesh and mod list actually cross referencing a bit later. A little busy right now :) ]