The different shadow settings in the ini : V

» Mon May 28, 2012 1:37 pm

Like many others here, I have tried tweaking the shadows to find a good compromise between good looking shadows and high fps.
For whoever is interested, here are the relevant settings from my Skyrimprefs.ini:

Spoiler

iBlurDeferredShadowMask=8:
This setting will blur your shadows, masking the low resolution of the shadows a bit.

fInteriorShadowDistance=2000.0000:
Interior shadow distance, doesn't have a overly strong effect for me. Probably because lowering it will usually mean more shadows being rendered, instead of nicer ones (see below).

fShadowDistance=3000.0000:
Exterior shadow distance. This one is pretty important. Larger values obviously mean shadows visible further away, BUT it also means the quality of the shadows will be reduced.
Additionally it can have a significant impact on performance. Lower values will give you much better performance, as it means the pc has to calculate less shadows.
So: low values mean good looking shadows and good performance but as you don't see them far away it will look strange when they appear while moving.

iShadowMapResolution=2048:
Also very important, controlls the shadow resolution, therefore the overall smoothness. I leave it at 2048 as higher values give a significant loss in fps for indoor scenes.

iShadowMode=3: Don't know about this one
iShadowMaskQuarter=4: Impacts how "crisp" your shadows are. Lower = less detailed I think, with 0 disabling indoor shadows. Too high will crash the game. I feel it makes shadows a bit more "agitated" while moving, which is why I prefer iBlurDeferredShadowMask.

fShadowBiasScale=0.15: Determines how high an object has to be (relative to the lightsource?) to cast a shadow.

And, from the display section in Skyrim.ini:

fSunShadowUpdateTime=0.0000: How fast the shadows move when sun position is updated (0 means they jump, reducing jittering)
fSunUpdateThreshold=0.5: How often the shadows update relative to the sun movement. Set to zero for constant updates.

However, the ini also has those two lines:

iShadowMapResolutionSecondary=512iShadowMapResolutionPrimary=1024

I can't seem to see any impact from those. Does anyone have some information on what they do?

» Mon May 28, 2012 1:33 pm

Like it says it's the shadow map resolution the lower the value the more pixelated the shadows will be, think of like a texture the lower the res the more it must be streched wich will result in nasty blocky shadows.

I'm not sure why there are two values though I have them set to the same value of 2048 wich makes the shadows bearable without giving me a performance hit. Still I try to ignore the shadows as no matter what you will tweak they will look horrible always..

» Tue May 29, 2012 2:09 am

Like it says it's the shadow map resolution the lower the value the more pixelated the shadows will be, think of like a texture the lower the res the more it must be streched wich will result in nasty blocky shadows.

Actually not quite, that's what iShadowMapResolution is for, those other two lines seem independend of iShadowMapResolution.

» Mon May 28, 2012 3:40 pm

iShadowMapResolutionSecondary=512
iShadowMapResolutionPrimary=1024

From tinkering with these two value seem to represent the total space allocated for that close ring of higher def shadows vs the secondary larger ring that extends out to the Shadow distance. Also from tinkering I found if you leave those values too low its detrimental to performance, I've currently got them both at 4096 with a shadow min distance of 1500 and max of 5000 and the shadows look like they 'should' vs the rest of the values like deferred blur etc. However if I were to say drop them both to 1024 my game slows down often and the shadows on a whole look way blockier. But yah I don't yet have a clear understanding of their relation in this particular puzzle.

The one I'm completely in the dark about is what this does:
iShadowSplitCount=2

No clue, none at all.

Oh but one you may as well throw in there is the iShadowBiasScale, which is the method by which you can tell the shadow engine to ignore drawing shadows on things beneath 'x' height. Ie the lower you set that the smaller the minimum height of an object needs to be before the shadow engine will include it and the higher that value the wierder shadows of regular sized things like characters look since the shadow only starts at that height. Example: at 0.25 my character's shadow doesn't really include his feet, its got from the ankles and up but not the feet themselves, meanwhile if I set the scale down to like .1 its got most of the feet but its also now drawing *alot* more shadows due to all the little short objects throughout the game world and is overall a lot more taxing on the shadow engine.

» Mon May 28, 2012 12:32 pm

I have no idea about iShadowSplitCount either.

Have tested different values and combinations for Primary and Secondary, bt could not see any differences in outdoor scenes.
Will test indoor to see if it might be related to indoor shadows...

Edit:
Nope, no visible effect. Maybe tied to something else that did not matter in my tests.

Have also added iShadowBiasScale to my OP.

» Mon May 28, 2012 3:48 pm

Found from that other thread with the guy talking about turning off quartering.
iDeferredShadowMask - The higher the setting the more it softens the indoor shdows.
iShadowMaskQuarter - The higher the setting the more it softens the outdoor shadows.

At least this is so far my understanding of how the two work. Still no clue on that splitcount, stupid shadow engine!

I'm also still trying to get a handle on what iShadowFilter does, what I do know is if its 0 then I don't have any shadows and if I set it to something like '8' in whiterun the whole map gets a rather grey sort of super shadow across it, oh and '8' completely slaughters FPS if I try to go inside of dragonreach.

ED: Btw that secondary & primary stuff: They tie into the range defined by fShadowLODStartFade, I believe primary is everything from 0 -> startfade and secondary is holding startfade -> shadowdistance/interiorshadowdistance.

Now this last chunk of info about the shadow engine annoys me personally to a very high degree: Its freakin sensitive to the size of your view of the game world. Try this: Muck with the FOV and you will notice the lower it is the higher detail you'll get your outdoor shadows(when going lower though you have to make the shadow engine redraw the spot by looking away or looking at something else, but increasing the fov will instantly reduce the shadow quality). For me this is brutal since I'm playing with 3x the effective view as their expected users so yah mah shadows suxxor and far as I can tell there's no way to just 'give the shadow engine more room', because I'd happily do so.

» Mon May 28, 2012 10:04 pm

Found from that other thread with the guy talking about turning off quartering.
iDeferredShadowMask - The higher the setting the more it softens the indoor shdows.
iShadowMaskQuarter - The higher the setting the more it softens the outdoor shadows.

Hm, I thought iBlurDefferedShadowmask is for outdoor shadows (as no matter what I do, indoor shadows don't blur for me) and iShadowMaskQuarter is the other way around.
At least this is what I gathered from my tweaks.

Ah, Skyrim's shadows, they never cease to amaze me... :-D

» Tue May 29, 2012 12:12 am

Another reason why they should build a new engine but sadly we are svck in 2008.

» Mon May 28, 2012 7:06 pm

I think

Another reason why they should build a new engine but sadly we are svck in 2006.

Fixed.

» Mon May 28, 2012 4:50 pm

If you look at FarCry's graphics then it's 2004 then.