Train Sim World 2 (and 1) Have A Mouse Axis Precision Problem. Demo + Rough Workaround

Problem summary:
Certain UE4 based games, including Train Sim World (and IIRC Sea of Thieves, though they might've fixed it since I last played), have a bug with the mouse where the axis precision (i.e. the amount of "steps" in each mouse movement) is incorrect, resulting in a kind of jitter or stutter when moving the mouse. Based on certain factors like mouse sensitivity, framerate and screen size, or just experience with PC/Mouse gaming in general, this may be more or less jarring, in my case, it has been pretty annoying for me since the first Train Sim World and so I have finally recorded some footage at three different mouse sensitivities to showcase the problem and have discovered a way to at least make it more bearable.

Footage of the problem:
I have used the input.ini config file to set the mouse sensitivity to three different levels:

0.03, which is a good balance for mouse responsiveness without being too slow for my taste.
0.07, which is, I think the default value.
0.15, which is a higher value I chose to better demonstrate the issue on video.

In order to get the best quality, watch on a Desktop computer and click the little cogwheel icon to get "HD" quality, you can also right click -> Open video in a new tab, to get a better view.

Sensitivity 0.03: https://gfycat.com/verifiableeminentkiskadee
Sensitivity 0.07: https://gfycat.com/infamousflamboyanthypsilophodon
Sensitivity 0.15: https://gfycat.com/richpastelauk

In order to prove that this isn't an issue with my mouse, or the selected DPI (which I had to reduce for the 0.15 sensitivity example) I made this "worst case" example using Ghostrunner, another UE4 game, but one which doesn't have the bug, in the example I used in-game 20% sensitivity (not sure how that translates to "Unreal Engine" sensitivity, though it felt the same as 0.15, if not faster) and the lowest DPI that I have enabled on my mouse (unfortunately the Logitech software is broken for me but it's about 250 or 300dpi).

Ghostrunner at 20% sensitivity: https://gfycat.com/importantshrillarmyworm

As you should hopefully see, there is indeed a problem with the way Train Sim World 2 is handling mouse input.

The Solution:
Without having access to the project file, it's hard to definitively troubleshoot this issue, though I was able to find this Reddit post: https://www.reddit.com/r/unrealengine/comments/kn2k8s/how_to_fix_mouse_stutterpixel_skipping/ which seems to describe the same issue, in the comments, the developer describes fixing the problem using methods that seem to only be exposed in the UE4 editor.

Unfortunately, I doubt this issue will be taken seriously as most people probably don't notice it, or just chalk it up to framerate related issues (which it isn't, note the stable 60fps in the clips). Though I would be happy to be proven wrong by the developers at Dovetail Games

The Workaround:
Since the problem originates from low axis precision, so a too low number of steps per a given distance, we can just increase the overall distance to, essentially, increase the density of steps, as shown in the post above, a sensitivity of 0.03 seems to largely eliminate the problem, at least on my system, and that without reducing the sensitivity too much. Here is how to apply the workaround:

Navigate to: %userprofile%\Documents\My Games\TrainSimWorld2\Saved\Config\WindowsNoEditor

(Edit: Fixed folder path)

Note: %userprofile% is an environment variable in Windows, so it will automatically be substituted by your username when pasted into the address bar of the Windows File Explorer.

Open "input.ini"

Insert this text (copy and paste) at the end of the file:

Code:

[/Script/Engine.InputSettings]
AxisConfig=(AxisKeyName="MouseX",AxisProperties=(DeadZone=0.000000,Sensitivity=0.03,Exponent=1.000000,bInvert=False))
AxisConfig=(AxisKeyName="MouseY",AxisProperties=(DeadZone=0.000000,Sensitivity=0.03,Exponent=1.000000,bInvert=False))

This may be problematic if you are used to a higher sensitivity, you can adjust it by changing "Sensitivity=0.??" though keep in mind that higher sensitivities mean more stutter.

I hope this helped someone

 

I must admit, I'm one of those who THOUGHT the janky mouse movement is due to optimization issues with the engine and my FPS anyway but after reading your post and actually thinking about it you are damn right!

I watched your videos and 0.03 definitly is what I would want to have
Thanks for already preparing the copy&paste entries, I'll add them to my input.ini and report back what I'm thinking and if I had to adjust anything (and what I found out by doing that).

Thanks, cool initiative!

 

It's much better IMHO, thanks!

 

This is amazing Martin Winkelmann - as someone who streams I've hated the jumpy motion. I've got a Razer Viper gaming mouse and it is twitchy as - which is awesome when you're in an FPS but kind of annoying in train sims. I used 0.01 for the sensitivity and its beautiful. I need to use the entire travel of my mouse mat when in cab but panning around outside its awesome. Nicely slow and smooth.

Paul

 

I've set this in my input.ini and I'm loving it! Thank you for the research on this one. The mouse behavior is probably the most annoying thing on the game.