How to force Motion Blur

Guide on forcing camera motion blur via a configuration file edit

Disclaimer - before you start

While searching online on the subject, it has become evident to me that some people have strong feelings against motion blur and just can't pass an opportunity to express them. Please... This guide isn't meant to wreak disputes or force anyone to use it, just to (perhaps) help those who might prefer to have motion blur. Hell, maybe I'm the only such weirdo out there, so what.

Introduction

Since the days of KF1, even when I had a high refresh rate monitor, I found KF's complete lack of motion blur very jarring and difficult for my eyes. With KF2, the issue still holds true. Especially since I switched to 60hz IPS panel and have mostly moved away from fast paced and FPS games.
So with my very recent recurrence of interest in the game, I've looked into this a bit more.

The regular motion blur setting in the game settings hardly does anything; the amount of blurring applied even during very fast paced turns is so minimal, it doesn't aid in motion fluidity at all, only very, very slightly de-sharpens the image.

The tweaks below are what I've been able to find / make work for myself.
They ONLY enable CAMERA driven motion blur.
I haven't been able to find a way to activate object motion blur, but camera motion blur does the job for me.
To elaborate: you only get motion blur when camera moves, rotates or shakes ( when you move or shoot too ), but not when you're completely static.

I've tried to get some understanding of the values / settings - to best I could, for now at least - and to provide reasonable description.

Some info regarding Motion Blur Post Process Effect can be found on UDK documentation site here[docs.unrealengine.com], however, it is not KF2-specific.

Tweaks

The needed tweaks are located in

%userprofile%\Documents\My Games\KillingFloor2\KFGame\Config\KFSystemSettings.ini

All of the following variables exist in the ini file to begin with; you can find them via search.

MotionBlur=True

• false corresponds to "off" setting in the video options menu

UseComputeMotionBlur=True

• this specifically enables the camera motion blur (not present in the options menu)

MotionBlurQuality=1

• 0 corresponds to "off" setting in the video options menu
  
• 1 corresponds to "on" setting in the video options menu

MotionBlurStaticScale=0.1

• amount (scale) of motion blur
  
• contrary to my initial assumptions, this is not the shutter angle / length, but the scale/multiplier for the effect. Default is 0.8, which felt too much; I dropped it to 0.1 and still get decent amount of blur
  
• the other one, MotionBlurDynamicScale, doesn't seem to do anything

Performance

I haven't seen a performance impact, but I guess your mileage may vary.
Share your experience if you want.
(Myself I'm currently on 1080Ti at 3840x2160, 60hz with vsync on, settings are mostly Ultra except unimportant stuff like filtering,shadows and reflections. FleX off.)
.

Screenshots

Below is a medium-speed turn left-to-right (camera pan):

no camera blur (only default motion blur)

MotionBlur=True
MotionBlurQuality=1
UseComputeMotionBlur=False

This is with default in-game motion blur option turned on. Notice how there's barely any blur,
just slight loss in sharpness on the zeds.

with camera blur

MotionBlur=True
MotionBlurQuality=1
UseComputeMotionBlur=True
MotionBlurStaticScale=0.1

More screenshots of regular gameplay:

Here's a random silly video with these exact settings. The video itself is unaltered original screen recording without any editing or color correction

Some additional notes

I excluded these things from "Tweaks" because I consider them irrelevant:

• this[docs.unrealengine.com] UDK documentation page references MotionBlurQuality values of up to 4, however, I don't think it applies to KF2 and I did not see any difference with values above 1
  
• there is also a console variable MotionBlurSoftEdge[docs.unrealengine.com] , in KF2 it is set to -1 (off). It's supposed to improve the smoothness of the blur. But even if changed, it resets each time the game is restarted, I couldn't get it to load from .ini files, and I really did not see it make any visual difference

Final words

I might revise the guide if I got something wrong or find something to update / correct in the future.
Considering I haven't tested this on other hardware, it is possible there are some more quirks or hardware based limitations. The abovementioned tweaks / variables might depend on some other settings.

[codname125]

Doesn't work on current build of KF2

[TheDarkSentinel]

unreal engine 3 motion blur sucks because i cant fuking see it and overall it looks bad

[FAB]

Interrestingly I use it not for it's image motion capability but for it's ability to annihilate screen tearring which is an odd result which i was notexpecting from such an FX. I use it in competitive games in that regard (high fps+ high refresh rate + a very small touch of MB.

[Urik]

Well, actually low fps is where motion blur helps the most, like in the movies it aids in perception / fluidity of motion at 24fps. So on 60hz it really helps (assuming v-sync is on). But at 144hz there wouldn't be as much point in it as there'd be much less of it (the amount of "smudge" length / blur directly depends on framerate). And when a 120+hz monitor drops below 100-90 fps, it often looks very jarring because of very fast response rate of the pixels.

[FAB]

i managed to find some procedures to test motion blure strenghts and effectiveness. You should find an area with a lot of contrast, preferably with a very bright spot and do horizontal left/right motions from slow to fast.

I noticed there is a very good exemple to test MB, using Trackmania, driving on a very open area (preferably using the SUV in town) in a small circle.

With a framerate below 150 i found motion blur to be problematic (on my 144Hz monitor at least) more than anything. So keep an eye on your framerate!

[FAB]

So after many hours testing in and out i finaly found something absolutly stunning. The version of the UE3 shipped with KF2 actually features per object motion blur as a bonus. This is absolutly massive!

With 0.15 static motion blur and 0 dynamics the game is a whole new experience, things are so smooth it felt like the Zeds were moving slower, but no it was just that the game is so silky smooth with POMB that it's a whole new experience.

Btw motion blur really shine with high fps and refresh rate.

I dropped the ReShade MB but kept the sharpening and SMAA. Now it makes me want this kind of MB in other games... but it's not something you can reproduce with a simple frame filter.

Thank you so much for this discovery man! <3

[Urik]

@FAB Interesting. I've never used third party enhancers, though I've heard about ReShade in relation to GTAV.
In-game motion blur has usually the least impact on fps performance because it uses engine's internal data (vector map or something) of what pixels are moving and kind of applies cheap realtime directional blur based on that data. It seems to be not fully supported in KF2 as only camera-movement blur is applied. But I guess I'm ok with that since when I'm stationary and aiming down sights, trying to make the shot, I wouldn't want things blurred.

I used to play and mess with / mod L4D2 a lot long time ago. I remember it does have some motion blur, but it wasn't very noticeable unless I was looking at a screenshot with like, a hunter or charger speeding by.
I remember Just Cause 2 had very noticeable motion blur, and it helped the fluidity a lot. But when examined close, you could see actual edges/samples of the smoothing on a screenshots/video.

[FAB]

In the end i use ReShade with a very subtle Motion Blur FX setting (to the point you don't actually have blur but it get rid of screen tearing like nothing else!) and LumaSharpen maxed out.

I think i might be losing a couple of fps but realy not much. I still like how UE3 does motion blur, it's doing it in an interresing way.

So far the best implementation i saw in a game was Left 4 Dead 2 and DOOM 4. If anyone is interrested i can share my ReShade Motion Blur settings.

Have fun guys!

PS : even for competitive gaming MB is awesome if you know what you're doing and have the hardware for it.

[FAB]

Alright after further testing i find that either MotionBlurStaticScale=0.010000 or 0.15000 are good values for my 144Hz monitor and for how i move my mouse.

And yes even 0.01 you can feel it, it's still more comfortable for the eyes than nothing. Anything inbetween 0.15 and 0.01 felt off.

[FAB]

This is great! I noticed it also blurs the weapons and the player character when in the gear tab. MotionBlurDynamicScale is a weird setting that kind of make the engine focus/defocus randomly and makes the textures blurry for nothing, I'd advise to set it to 0 and tweak MotionBlurStaticScale instead (as you said 0.100000 seems perfect). MotionBlur skinning is hard to test, I'm not even sure it works in this game so i keep it at 1.

EDIT : tried with ReShade. It's taxing quite a bit on the GPU, which is weird as it usualy doesn't tax anything on DX9 games. I guess this beeing DX11 the implementation is maybe worse. ReShade will make you lose FPS even with no effects enabled. So I will stick with your method of UE3 motion blur. Shame because I wanted to add sharpening and colorfulness fx with ReShade.

I'm sure there is a way to sharpen the textures in the .ini i just don't know how to do it (still searching ;) )