Jump to content


* * * * * 2 votes

Skid Fun Driver View Display Calibration

display driver view Skid Fun

  • Please log in to reply
18 replies to this topic

#1 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 13 2016 - 09:32 AM

Now another reason to appreciate one of simracing's most unique and fastest circle tracks ever.

A properly calibrated display enables a driver to more easily and accurately see the track ahead, as well as see the true placement of track side objects like trees, curbs, hay bales, etc. that may very much influence driver inputs while racing.

The benefit of proper calibration is confidence that car setups and car performance is in response to the track and not compromised by a distorted view.

If the display is out of sync, a user may think the car is turning in too quickly, or not quickly enough, seeming to understeer or oversteer. They may miss brake points or have difficulty setting brake bias when actually it is driver perception errors that are being misdiagnosed as setup and driving errors.

How to use the Skid Fun Cauldron of Fire Driver View Display Calibrator:

Drive up to the cauldron and find the 50-Meter line. It is the first white line away from the cauldron and it is labeled 50M.

Drive around until you find the pit girl with the checkered flag. Notice that beyond her on the far outside ring is another pit girl, (that appears at that distance to be a small vertical line on the horizon).

Imagine a line on the track from the far away pit girl to the checkered flag pit girl that extends behind you past the 50-meter line. Park the car on the 50-meter line so the in-car driver's head is over the intersection of the two lines, facing the checkered flag pit girl at a tangent to the cauldron.

From this position, the angle between the in-car driver head and the two outside pit girls to the left and right is 42-degrees, (the calibration angle), as shown below in Bob Simpson's drawing.

Calibrate user view by adjusting FOV until the calibration angle from your eyes to the pit girls is equal to 42-degrees.

To do this, use a protractor as a calibration tool by placing it on the bridge of your nose and hold it level in front of the display. Or using a protractor, cut a piece of heavy paper so two edges make a 42deg angle...easier than trying to read a protractor from an inch or so away.

If the left and right side pit girls are inside 42degs on the calibration tool, reduce FOV until the lines from your eyes align with the 42deg lines and point to the pit girls.

If the left and right pit girls are outside 42degs, increase FOV to bring them closer together, until the lines on the calibration tool point to the pit girls.

This is a new Skid Fun feature of uncertain practical utility.
It is not tested by a team of beta testers, so early adopters are the beta team and are welcome to comment on any results.

Get the track here: Skid Fun Skid Pad

Thanks to Bob Simpson and ginetto for help and support with this fun project.

Attached Files


Edited by John Woods, Mar 17 2016 - 08:54 AM.


#2 Paddy the Irishman

Paddy the Irishman

    Paddy the Irishman

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 796 posts
  • Gender:Male
  • Location:Bexhill on Sea, E. Sussex, England
  • Interests:GPL; Model Cars; Photography.
  • Sim interest:GPL

Posted Mar 13 2016 - 10:59 AM

Well, I have heard of men going cross-eyed over pit girls before now – but in GPL ?

Seriously, it might be a good help. Thank you.

#3 Robert Fleurke

Robert Fleurke

    Denny Hulme

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 467 posts
  • Gender:Male
  • Location:Groningen, the Netherlands
  • Interests:Life
  • Sim interest:GPL

Posted Mar 14 2016 - 11:14 AM

Very interesting John. Have yet to check it out, but currently are using 90 degrees FOV with 1920x1080 resolution. For me it is a compromise between awareness (online), mirrors visible, and immersion (having the cockpit close to my wheel). For only offline racing I would use less FOV probably.

Will check it out and report back here.

#4 Robert Fleurke

Robert Fleurke

    Denny Hulme

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 467 posts
  • Gender:Male
  • Location:Groningen, the Netherlands
  • Interests:Life
  • Sim interest:GPL

Posted Mar 14 2016 - 12:58 PM

Isn't this depending also how close your monitor is to your head!? I mean when closing down the monitor, the angle would increase, and viceversa. I remember at Remco Hitman's I was very close to his diaprojector screen. This will alter the angles, if I am understanding it correctly.

Surely for offline use this would be great to find the optimal driver cockpit view, but with online racing you simple want to take into account awareness having slightly more FOV!?

Just some thoughts, I haven't scientifically measured the angles...

#5 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 14 2016 - 02:50 PM

View PostRobert Fleurke, on Mar 14 2016 - 12:58 PM, said:

Isn't this depending also how close your monitor is to your head!?

Yes or no.
If the display is too small to accurately calibrate, it would have to be moved closer to user's eyes.
If using the calibration tool, (the paper cut to 42deg angle), can be applied within the width of the display, it does not matter how far the display is to the user's eyes.

While the importance of display calibration is well known, not aware of any race sim having a display calibration matrix on a test track, so as far as I know this is a first.

Many years ago on RSC there was some discussion about some/many aliens using very narrow FOV, around 40-50degs, with 42deg seeming to be the most popular. So for years after reading that I used 42deg because testing revealed that made me fastest. It could be those early aliens were more sensitive to getting in sync with virtual space?

Using the calibration angle at Skid Fun find my rig is in sync with virtual space at 90deg FOV, down from the 105 I had been using.
The difference after dialing it in is very subtle, but it is apparent and seems to make for smoother driving and less having to catch the car after beginning a move. (If that makes any sense).

Even if not possible to get it completely into sync because of display size etc, getting it close as possible would surely help.

The point of calibration is to zero out effects that are caused by being out of calibration, that lead to having to compensate for them with setup and while driving.
There is no doubt about there being effects.
Have to think poor calibration would have the same effect off-line or on-line.

Edited by John Woods, Mar 14 2016 - 02:58 PM.


#6 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 253 posts
  • Sim interest:GPL and P&G

Posted Mar 14 2016 - 03:50 PM

Is this some kind of early April Fool's joke???

#7 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 14 2016 - 04:02 PM

View Postone2fwee, on Mar 14 2016 - 03:50 PM, said:

Is this some kind of early April Fool's joke???

Well it would have to be on me for sure. But I didn't invent all this stuff about calibrating a video game display.

:)

Edited by John Woods, Mar 14 2016 - 04:04 PM.


#8 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 253 posts
  • Sim interest:GPL and P&G

Posted Mar 14 2016 - 04:11 PM

I've tried to explain to you countless times about FOV though...

The correct FOV to use depends how far away you are from your monitor and how big it is. Unless you have a big monitor or triple screens this can be a compromise, as the correct FOV will usually mean you are cutting off your mirrors and cannot see the inside of hairpins. You can use virtual mirrors to alleviate the former, but the latter is something you will have to deal with and you can use a slightly too high FOV if this is still a problem. You should try and move your screen as close as possible (that doesn't hurt your eyes) as a closer and/or bigger screen means a greater correct FOV.
GPL uses the horizontal axis to set its FOV, so the setting in GEM+ corresponds to this. (I don't imagine that the "no black bars" patch changes this but since i haven't tried it and don't know its implementation you would have to ask the authors).

You don't need to do any faffing about with protractors or anything or driving on any track to measure.
You measure the width of your screen and your distance away from it and then calculate the FOV from that, then you enter that value as the FOV in GEM+
In fact you can use FOV calculations for many things - i was thinking of going through all of the old car camera files and editing them for use with widescreen displays as they were designed for 4:3 and using calculations to achieve this so they are HOR+ instead of HOR- as they are currently.

Seriously, search my posts, i have mentioned countless times about FOV.
I would link myself but for some reason when i go and "show posts / topics" for me it only gives me very recent ones for some strange reason.

Edited by one2fwee, Mar 14 2016 - 04:17 PM.


#9 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 14 2016 - 04:46 PM

The neat thing about protractors or paper cut to a specific angle is it does not matter what size a monitor is or how far away the user's eyes are from the screen.

Plus a big factor for me is there is no way am I going to do anything beyond a = bc algebra without having to learn it again and it was misery the first time too many years ago.

This way, no measurement, no calculations, and the same device works the same way for everyone with a display big enough or close enough to take advantage of it.

Edited by John Woods, Mar 14 2016 - 05:59 PM.


#10 Bob Simpson

Bob Simpson

    The answer man

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,214 posts
  • Gender:Male
  • Location:Ottawa
  • Sim interest:GPL

Posted Mar 14 2016 - 05:53 PM

View Postone2fwee, on Mar 14 2016 - 04:11 PM, said:

I've tried to explain to you countless times about FOV though...

The correct FOV to use depends how far away you are from your monitor and how big it is.

No.  If you think of the monitor as a window or box placed in front of you in real life, when you move closer to it, you'll get a wider range of view, but the objects in the distance will not get closer together or farther apart.  This is what they do when you change FOV, which is like changing a zoom view in a camera lens.

#11 one2fwee

one2fwee

    Denny Hulme

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 253 posts
  • Sim interest:GPL and P&G

Posted Mar 14 2016 - 06:09 PM

Huh where did i say otherwise Bob?

What you quoted is correct - if you buy a larger screen, or put the screen closer to you then the correct FOV will be greater.


I found a post of mine that links to lots of other posts that have the formulae and information if you are interested John.
http://srmz.net/inde...ew"#entry102410

In fact i think i might put a link in my signature now, so it's less easily "lost".
Oh, it seems signatures are only visible to logged in members - oh well.

Edited by one2fwee, Mar 14 2016 - 06:13 PM.


#12 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 14 2016 - 06:37 PM

View Postone2fwee, on Mar 14 2016 - 06:09 PM, said:

In fact i think i might put a link in my signature now, so it's less easily "lost".

Linked also in Tech Section at gpllinks "Setting Realistic FOV," (to post #32).
Thanks for finding that and posting here.

#13 Bob Simpson

Bob Simpson

    The answer man

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,214 posts
  • Gender:Male
  • Location:Ottawa
  • Sim interest:GPL

Posted Mar 14 2016 - 06:44 PM

Yes, I see what you're saying.  But first you have to establish a distance from the monitor, then set the FOV so that the objects at X distance are the correct Y angle or Z distance apart.  Once the FOV is set, if you move your head forward or back dramatically while driving, the Z dimension won't change on your monitor, which is unrealistic.

#14 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 14 2016 - 09:25 PM

Think I like window vs. camera idea better.

Not sure about what X, Y, and Zs we are working with?
X = distance from eye to monitor
Y = angle from eye to each edge of display
Z = distance between two given virtual space objects in view on display

If its like a window, there would be no change in Z when FOV is changed, just a wider or narrower view of the same thing.

But its a camera for sure and Z changes relative to the display when FOV is changed as well as the angles to the objects at each end of Z.
Not only that, the focal plane changes as well, unlike a window and exactly like a telephoto lens.
What does that do?
A telephoto lens foreshortens depth of field and distorts the user's perception of distance in virtual space?
(Or is that just vector graphics?)

Anyway, this would be why calibration by any means is important to accurate perception.

The projection of 3D space is modified by changing position of the camera, fore and aft, and changing its FOV.
So there are specific values for all those variables, unique to each user's display, that will yield an accurate portrayal of time/space.

Have to assume there was some interest in this when Grand Prix Legends was created, as no doubt some analysis resulted in establishing 77.xx as the driver view FOV.
What were they thinking?
We might imagine the reasoning began with estimation of typical distance from a user's eye to the then typical 15in or 17in CRT, then a lot of math, testing, and discussion.
N2K3 has an FOV adjustment in its menu, (iirc), so there had to have been by then recognition of the need to modify it to adapt FOV to user's eye?

Um, hm, feeling a bit past the edge of smart here, and its late where I am, so please don't forget with me its all questions and guesses.

Edited by John Woods, Mar 15 2016 - 05:15 AM.


#15 John Woods

John Woods

    Be Somebody

  • Supporter
  • PipPipPipPipPipPipPipPipPipPip
  • 2,113 posts
  • Gender:Male
  • Interests:Too Much Fun
  • Sim interest:GPL

Posted Mar 15 2016 - 12:25 PM

Bob, now I understand what x. y.and z you mean.
Think before I just dropped out the significance of the word "objects" altogether.
:P

Yes, do agree a camera's view is not at all like a real view.
Sure you agree that is why calibration is essential.

We know for sure its a camera view, (not a simulation of a real view), because tires seem to roll backwards.

When first using Grand Prix Legends, thought to properly "see" it was necessary to imagine being in the virtual car and having the default driver view camera as my view. In other words, instead of being me, sitting outside the virtual space, had to imagine being in the little car on the screen in front of me. So there was a definite difference between me inside and outside the virtual space.

Then finally realized wanting to see the virtual space from my POV sitting outside of it but as if sitting in the virtual car. That's when all this saga began. So for years, once finding out very little but enough about it, avoided the need to calculate anything by skipping that and going straight to a protractor that told me the angle from my eyes to the edges of the display. This is completely consistent with one2fwee's mathematics given each are done correctly. Its the same angle after all either way.

Every time something changed that effected display calibration, had to find the protractor and fumble around trying to decide what for sure the new angle was, (and I have a big protractor).
Then, all of my setups were shot because now virtual space looked different than before and I was reacting on track in some confused combination of prior habit and new awareness.

Not sure yet, because this is new, but having the calibration matrix inside the virtual space may result in not having to adapt to new spatial awareness or tweaking a setup to new hardware configuration. Just dial it in again and you are good to go. Perhaps, as if the display is a window?

Also, given two users sharing setups there might be no need to adjust them to accommodate each other's display configuration if both displays are dialed in on Skid Fun?

But those are really long shot guesses, so...file for now with all my other fantasy theories.

Edited by John Woods, Mar 15 2016 - 02:14 PM.






Also tagged with one or more of these keywords: display, driver view, Skid Fun

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

Sim Racing Links