SUBSIM Radio Room Forums - View Single Post - GWX

danmir · 06-05-07, 10:31 AM

Hey,

I just purchased SHIII about 5 days ago, and installed GWX. I'm new here, so hey all. I've been lurking here the last week or so, figuring out the lingo. Took me a while to "get" AOB. And apologies in advance for noob questions coming!

I, too, was wondering about the scale, so I tried to puzzle it out. I took empirical data at the 10x mag, and charted it in excel. Basically I took measurements with the stadometer at 15, 13, 12, 11, 10, 9, 8, 5 ticks. I'm at work now, I did the charting at home, but the excel sheet linear estimation of the degrees per tick was about 0.156 degrees per tick.

I thought about this, and I have concluded that in GWX at 10x magnification, there are 0.15 degrees per tick. Reason?

- At 1.5x mag, they are 1 degrees per tick. You can verify this yourself, and it makes sense it would work this way.
- At 10x mag the scope tick scale does not stretch or anything.
- Key info: 1.5 / 10 = 0.15
- 1 degree tick gets subdivided by the ratio of the magnification, thus 0.15 degrees per tick
- I think the game engine funny rounding/flooring for the displayed angle moved my measured data slightly off accounting for the 0.156 linear estimation.

What I did find puzzling though was at the even marks, the measured angle would increment right at the marks, where if it was rounding as I would expect, it would be stable at the even marks and sensitive at the odd number marks. Ie @ 8, 8*0.15 = 1.2 degrees. at 7.8*0.15=1.17~=1.2, 8.2*0.15=1.23~=1.2. If it were rounding, i would expect it to be stable at 1.2 degrees at 8 ticks, but its 1.1 just under 8, 1.2 just over. From this I must conclude the displayed degrees aren't rounded; it is floored.

However, even though it displays the floored angle, I think it still uses a more precise angle for range calcs. I have noticed moving it up and down just a bit on the range measurement for which it gives the same angle on the display does give different ranges.

Assuming the top ticks follow the same scale, this leads to some interesting possibilities of measuring the apparent angular length of the ship, knowing range, and the actual length of the ship, you could compute the AOB.

AOB = acos(apparent_length/actual_length)
apparent_length ~= range * sin (angular_length)

AOB ~= acos(range*sin(angular_length)/actual_length)

AOB ~= acos(range*sin(horizontal_ticks*0.15)/actual_length)

06-05-07, 10:31 AM	#3
danmir Swabbie Join Date: Jun 2007 Posts: 12 Downloads: 0 Uploads: 0	Hey, I just purchased SHIII about 5 days ago, and installed GWX. I'm new here, so hey all. I've been lurking here the last week or so, figuring out the lingo. Took me a while to "get" AOB. And apologies in advance for noob questions coming! I, too, was wondering about the scale, so I tried to puzzle it out. I took empirical data at the 10x mag, and charted it in excel. Basically I took measurements with the stadometer at 15, 13, 12, 11, 10, 9, 8, 5 ticks. I'm at work now, I did the charting at home, but the excel sheet linear estimation of the degrees per tick was about 0.156 degrees per tick. I thought about this, and I have concluded that in GWX at 10x magnification, there are 0.15 degrees per tick. Reason? - At 1.5x mag, they are 1 degrees per tick. You can verify this yourself, and it makes sense it would work this way. - At 10x mag the scope tick scale does not stretch or anything. - Key info: 1.5 / 10 = 0.15 - 1 degree tick gets subdivided by the ratio of the magnification, thus 0.15 degrees per tick - I think the game engine funny rounding/flooring for the displayed angle moved my measured data slightly off accounting for the 0.156 linear estimation. What I did find puzzling though was at the even marks, the measured angle would increment right at the marks, where if it was rounding as I would expect, it would be stable at the even marks and sensitive at the odd number marks. Ie @ 8, 80.15 = 1.2 degrees. at 7.80.15=1.17~=1.2, 8.20.15=1.23~=1.2. If it were rounding, i would expect it to be stable at 1.2 degrees at 8 ticks, but its 1.1 just under 8, 1.2 just over. From this I must conclude the displayed degrees aren't rounded; it is floored. However, even though it displays the floored angle, I think it still uses a more precise angle for range calcs. I have noticed moving it up and down just a bit on the range measurement for which it gives the same angle on the display does give different ranges. Assuming the top ticks follow the same scale, this leads to some interesting possibilities of measuring the apparent angular length of the ship, knowing range, and the actual length of the ship, you could compute the AOB. AOB = acos(apparent_length/actual_length) apparent_length ~= range sin (angular_length) AOB ~= acos(rangesin(angular_length)/actual_length) AOB ~= acos(rangesin(horizontal_ticks*0.15)/actual_length)