FSDreamTeam forum

General Category => Unofficial F/A-18 Acceleration Pack board => Topic started by: virtuali on November 17, 2007, 01:11:56 am

Title: HUD Calibration
Post by: virtuali on November 17, 2007, 01:11:56 am
Maybe not many have noticed it, but it's possible to calibrate the pitch ladder of the F/A-18 HUD to adjust the waterline to the scenery view, because the two might be or not in sync, depening on the eye position (like you were adjusting your pilot's seat up/down) and the zoom factor (this is of course fixed in real life...)

Just rotate the central screw on the HUD assembly, to align the pitch ladder waterline with the actual horizon...

Title: Re: HUD Calibration
Post by: islandjet on November 17, 2007, 03:20:37 pm
That's an almost frightening level of detail.

AWESOME..Thanks!
Title: Re: HUD Calibration
Post by: Intrepid on November 17, 2007, 06:48:08 pm
That's incredible! thanks it should make it easier to land on the carrier
this is the most impressive simI have ever had the pleasure to enjoy
THANKS TO ALL INVOLVED
Randy
Title: Re: HUD Calibration
Post by: thomasnc41 on November 18, 2007, 02:59:03 pm
Not sure I understand what this adjustment does.   I see the adjustment screw and see it move the ladder but at what point do I calibrate and what should I be seeing.  Anybody got a good picture that might help me to understand the calibration?  Any help would be appreciated.

Thanks, Tom
Title: Re: HUD Calibration
Post by: virtuali on November 18, 2007, 03:45:37 pm
The calibration should allow to match the HUD horizon line with the scenery actual horizon. The matching might be accurate or not, depending on your eyeposition and the zoom factor so, whenever you change one of these, you should calibrate the HUD accordingly.
Title: Re: HUD Calibration
Post by: thomasnc41 on November 18, 2007, 04:57:53 pm
Is the calibration done while flying flat and level at a certain altitude of can it be done at anytime during the flight or approach?  Sorry its taking me so long to grasp this but I just don't understand what is taking place.


Thanks again,  Tom
Title: Re: HUD Calibration
Post by: virtuali on November 18, 2007, 06:18:25 pm
This is better done when sitting on ground.
Title: Re: HUD Calibration
Post by: thomasnc41 on November 19, 2007, 10:16:58 am
virtuali,

Thanks for the quick responses.  I'm still missing something.  Would it possible for you to set your Hornet at KILM RWY6 with the correct calibration
set and do a screen capture, then post the photo so I can see it?

I do understand most of the avionics on the the FA/18 but this calibration adjustment is not coming to me and I really would like to understand.  I somewhat obsessed with this airplane. 

Again Thanks, Tom
Title: Re: HUD Calibration
Post by: islandjet on November 19, 2007, 02:37:01 pm
The calibration is all relative. At different airspeeds the aircraft flies level at different angle of attack (or alpha). You should be in straight and level flight to calibrate. Then the HUD is calibrated for THAT cruise attitude (and power setting) only. Hence whenever you do a maneuver, you simply return the HUD to the calibrated zero and you will be straight and level again.

It’s all relative as calibrated zero will change depending on your power setting (hence it being adjustable) and it’s really not a big deal. Most real world aircrafts have this including trainer Cessna 172s

The one time you should NOT calibrate is when you are sitting on the ground. This is because the aircraft sits with a nose down attitude and hence not really level.

-iJ
Title: Re: HUD Calibration
Post by: virtuali on November 19, 2007, 03:25:52 pm
In our case, the HUD calibration is only done to allow for pilots of different heights! In real life you would have change the pilot's seat height to match some reference points for the HUD. Since in FS we can simulate pilots with different heights ( or seat height adjustment ) by using the keys to move the eyeposition up/down, the HUD calibration was put there as a compensating factor.

Title: Re: HUD Calibration
Post by: Sundowner on November 23, 2007, 12:56:41 am
Is there a way to move the HUD texture ahead, lets say... 20ft and enlarge it, so it would be semi-collimated ?
Title: Re: HUD Calibration
Post by: virtuali on November 23, 2007, 07:09:46 am
Is there a way to move the HUD texture ahead, lets say... 20ft and enlarge it, so it would be semi-collimated ?

That would require updating the 3d model, and it's not something we can do now.

However, we used that method with the Phantom gunsight, to give the illusion of being collimated, it would need to be moved way more than 20 ft, don't recall exactly how it was on the Phantom, but was quite far.

There are also issues with that method: there's no 3d clipping so, if you moved your head sideways in the Phantom, the gunsight would still appear, hovering in the air in front of you, instead of being clipped to the hud glass.

The real solution would have been leaving the hud as it is now, and collimating via software but, unfortunately, that would require knowing the actual eye position. Via Simconnect, is possible to retrieve only the default eye position (that one you get when pressing ALT+Space to reset it), and the offset calculated by the head latency simulation. There's no way to get the eye position if that has been translated from default, for example with TrackIR. 

I've been asking to have this capatibility, but it didn't make it. In fact, the calibration screw we have now, it's basically a leftover of the preparation work that was done in anticipation to make the hud fully collimated, in case the ability to read the eye position would appeared.

We can only hope we'll eventually get that feature in an eventual upcoming Simconnect update, but to get advantadge of it, we'll have make another airplane that will use it.
Title: Re: HUD Calibration
Post by: Sundowner on November 23, 2007, 01:17:42 pm
The eye position was the second thing I wanted to ask, thanks for clarifying both.
Title: Re: HUD Calibration
Post by: crim3 on December 17, 2007, 11:59:45 am
Is there a way to move the HUD texture ahead, lets say... 20ft and enlarge it, so it would be semi-collimated ?
That would require updating the 3d model, and it's not something we can do now.
...
I've been flying sims during the last year in stereoscopic mode, in my case thanks to an HMD, and nothing beats the joy of perceiving real height when you lift off! When the Acceleration Pack came out, first thing I tested was if the HUD was collimated, what becomes critical in stereoscopic. Well, it is not, but I have just seen in this thread that you took it into account, and I'm very glad that at least it is not something ignored by you.

I'm having very good hours in the f-18, thank you for your work.