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FFB lut generator

Author Topic: FFB lut generator  (Read 17307 times)

Rolz

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FFB lut generator
« on: April 09, 2016, 10:08:59 AM »
Thought I'd put this in a separate post so people see it.

Firstly thanks Marty for pointing it out.

What is this?
This is a tool that produces an FFB lookup table for AC. It is used to (hopefully) correct the non-linear behaviour of the motors located on our steering wheels.

http://www.assettocorsa.net/forum/index.php?threads/lut-generator-for-ac.31699/

Been given a pretty decent rap by some AC mod contributors...



Offline Wally

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Re: FFB lut generator
« Reply #1 on: April 09, 2016, 11:22:49 AM »
It will be interesting to try. One thing I read somewhere is that some wheels are non-linear by design, e.g. to produce a stronger force output at lower rotation to compensate for something or other (as you can see, details in my head are sketchy). But the proof will be to try it and see what it feels like.
“You can please some of the people all of the time, you can please all of the people some of the time, but you can’t please all of the people all of the time”

Offline marty

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Re: FFB lut generator
« Reply #2 on: April 09, 2016, 03:39:22 PM »
Since I ran this it has made a fairly big change to my g27, clearly shows much more linear FFB as I now get more feedback all through the range even with total force higher then I had before. There is a bit more road feel but mostly its a better progression of grip gain and loss which in turn gives much better feel closer to the limit.

Offline grat

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Re: FFB lut generator
« Reply #3 on: April 09, 2016, 05:31:17 PM »
Thought I'd put this in a separate post so people see it.

Firstly thanks Marty for pointing it out.

What is this?
This is a tool that produces an FFB lookup table for AC. It is used to (hopefully) correct the non-linear behaviour of the motors located on our steering wheels.

http://www.assettocorsa.net/forum/index.php?threads/lut-generator-for-ac.31699/

Been given a pretty decent rap by some AC mod contributors...
Didn't you buy a CSW V2? I thought it was supposed to be quite linear (bar maybe a 5% minimal force needed).

Rolz

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Re: FFB lut generator
« Reply #4 on: April 09, 2016, 06:00:38 PM »
That's what I've been reading, but no harm in seeing what it does :)

Offline Wally

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Re: FFB lut generator
« Reply #5 on: April 10, 2016, 08:52:49 AM »
This is my T500 at 50% overall strength (blue), and the LUT that is generated (red). As you can see, it's already pretty linear, but with the LUT I feel more straight line road bumps. It felt a little too "noisy", so I reduced the first 3 LUT values by 0.25x, 0.5x and 0.75x, and it smoothed the very bumpy road feel a bit.

“You can please some of the people all of the time, you can please all of the people some of the time, but you can’t please all of the people all of the time”

Offline Guybrush Threepwood

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Re: FFB lut generator
« Reply #6 on: April 10, 2016, 10:44:26 AM »
Is it easy to use and then abandon if need be?

Offline grat

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Re: FFB lut generator
« Reply #7 on: April 10, 2016, 10:47:37 AM »
Is it easy to use and then abandon if need be?
Yeah, I guess so. It's just a one file you have to change + a new controllers profile. So you can have a safe copy of the old one and replace and then run the old profile.

Rolz

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Re: FFB lut generator
« Reply #8 on: April 10, 2016, 10:57:41 AM »
basically the ini file you modify for it just do a copy and revert back if you want. :)

Wally how do you do that graph?

Offline grat

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Re: FFB lut generator
« Reply #9 on: April 10, 2016, 10:59:28 AM »
This is my Wheelcheck outcome and LUT. It is for a Fanatec GT2 (which seems surprisingly linear after the dead-zone). I am surprised by the fact that I was running the hardware at 90%FF, which I thought it meant capped at 90% in fanatec wheels, but the wheelcheck shows no difference.

I have made a 0 dead-zone profile in AC now and testing. Seems ok, though not much of a difference (as expected from graph) but the wheel got a bit warm, something it did not do before.

Link to picture: https://www.dropbox.com/s/gujezanexlbcacs/LUT.png?dl=0

Offline grat

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Re: FFB lut generator
« Reply #10 on: April 10, 2016, 11:01:10 AM »
basically the ini file you modify for it just do a copy and revert back if you want. :)

Wally how do you do that graph?
Rolz, open the log and the LUT on excel. You have to normalize DeltaXDeg, i.e. DeltaXDeg/max(DeltaXDeg) to get it scaled 0 to 1. Then basically you graph DeltaXDeg and LUT (possibly putting "force" as the X axis labels as I did.

Offline gawaterman

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Re: FFB lut generator
« Reply #11 on: April 10, 2016, 11:59:02 AM »
Where do you change those values Wally?
My T500 feels the same as yours but more so under brakes. Get a real chattering thru the wheel as you brake hard. Not sure which file your referring to.

Offline grat

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Re: FFB lut generator
« Reply #12 on: April 10, 2016, 12:10:04 PM »
Where do you change those values Wally?
My T500 feels the same as yours but more so under brakes. Get a real chattering thru the wheel as you brake hard. Not sure which file your referring to.
He is talking about the LUT file generated with the procedure described in the link in Rolz's first post.

Offline gawaterman

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Re: FFB lut generator
« Reply #13 on: April 10, 2016, 12:29:53 PM »
Is this the .csv or the .lut file?
If I open the csv with excell I see nothing or if its the lut file what do I open that with?

Offline grat

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Re: FFB lut generator
« Reply #14 on: April 10, 2016, 01:32:09 PM »
Is this the .csv or the .lut file?
If I open the csv with excell I see nothing or if its the lut file what do I open that with?
The line representing your wheel's behaviour is the last column of the csv file, but normalized to get values between 0 and 1. The line representing the LUT is the last column of the lut fille---you can open it with excel and tell excel that the columns are delimited by the symbol | .

 

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