German Panzer Optics

[dibbler67]

Nice. Do tank optics have realistic zoom and fov?

They are 'relatively' realistic, for practical reasons. There will be a difference between a 15 degree and 25 degree scope but neither will be truly that size. This is because 25 degrees comes out to like 400 - 500 pixels on a 1080p screen which is too small to make the sights usable.

 

[Marsalkka Mahtimeisseli]

They are 'relatively' realistic, for practical reasons. There will be a difference between a 15 degree and 25 degree scope but neither will be truly that size. This is because 25 degrees comes out to like 400 - 500 pixels on a 1080p screen which is too small to make the sights usable.

Doesn't it depend on what FOV the player is using? And did you add the zoom in the calculations? I calculated that a player who plays with a FOV of 91 degrees (in-game maximum without tweaking the .ini files) and the resolution of 1920 x 1080, the reticle should be 621 pixels wide with the TOP sight (2,5 magnification and 15 degree FOV). I'm not very sure about my calculations, so if someone has a different result, please share

 

[aaz777]

too small to make sights usable? why?
If scope has magnification, its already very useful, doesnt matter whats FOV.

TOP with 15 degrees and 2,5 magnification will take 800 pixels of 1920res monitor, its ~0,4 of screen.

 

[dibbler67]

We might all be using different methods

I'm fairly certain that the vertical FOV is locked, and I did some trig assuming this was 90 degrees.
I assumed a right isosceles triangle with the hypotenuse formed by the chord between two points on a circle, 90 degrees apart of length = the height of the screen. The center of the circle is the viewing point. Projecting some angle theta on the screen I found would give a length of something like:

L = h*tan(theta / 2)

where h is the screen height in units.

This could of course be totally wrong

Aaz: 800 / (1920 x 1080) is actually something like 0.04 percent (!) of the screen area

I think applying my formula to the horizontal screen resolution should work, but it will give odd results for weird aspect ratios.

 

[aaz777]

800/1920 ~ 41,7 % ( only width of screen )
800*800/1920*1080 = 640000 / 2073600 ~ 30,8 %

 

[Marsalkka Mahtimeisseli]

This is how I calculated the width of the area used by TOP sight with "triangles", the picture should clarify my thoughts:

Let's imagine that you are a camera directly above a soldier, who is a single point in a 2D coordinate system. Soldiers horizontal FOV forms a triangle, which one angle is 91 degrees as the horizontal FOV in the game (phase 1 in the picture). If you draw a single line in the middle of the triangle, you get a right-angled triangle, which one angle is 45,5 degrees. From that you can calculate, that when triangle's bottom leg is 1x, then the other leg is ~1,02x (phase 2). So in practice, an object 1 meter away should be 1,02 meters wide to fill half of the horizontal width of the screen in the game.

TOP sight has 2,5 magnification, so the same object should fill same amount of screen when it's 2,5 times longer distance from the soldier. So now we can imagine a right-angled triangle with a bottom leg of 2,5x and the other leg same ~1,02x. So soldier's "half FOV" is 22,15 degrees (phase 3), and whole FOV is 44,3 when the same ~1,02x object fills a half of the screen.

Now we only have to calculate what is the width of the area seen from the TOP sight. When the FOV in that tank optic is 15 degrees, we again can make a right-angled triangle by drawing a line from the middle of it. So we get a right-angled triangle with one angle of 7,5 degrees. When the bottom leg is 2,5x (TOP sight magnification), the other leg is ~0,33x (phase 4).

Now what does that mean at the monitor? Well if ~1,02x is a half of monitor's width (960 pixels), then ~0,33 is 310,5 pixels, and that's only one half. So by that the aiming reticle should be 621 pixels wide (phase 5).

Things that worry me in these calculations are "did I calculate the problem in a right way" and "how those reticles are drawn on the screen". I've modded another game succesfully with these calculations, but the aiming reticles may be drawn in a different way in RO2.

And aaz, shouldn't you calculate the area covered by a reticle with the formula from the area of a circle? Pi times the square of the radius; πr^2

 

[aaz777]

i dont say that your method of calculation is wrong, but i will just do my own calculation using 3ds max, i hope it will match with your
I am using 91 FOV, but lets say its 90 because it will be easier. I ve " modelled " my 1920x1080 screen in 3ds max

TOP scope FOV is 15 degrees ( 90 / 6 ), so we cut our screen on 6 parts and middle one will be scope's width.

( picture on screen is just random screenshot )

TOP magnification is 2,5x, so we increase our middle sector in 2,5 times

Then i put a circle inside this middle sector:

So, this is how TOP should look on 1920x1080 res monitor with 90 FOV in game:

 

[morticore]

Seems logic for me.

 

[dibbler67]

I will try to illustrate my thoughts when I get home

aaz, your method can't work because the screen is not a curved surface. More specifically the screen doesn't form part of a sphere with the center at the camera location.

The screen is a like chord on a circle or a plane intersecting a sphere. The amount of area or length swept by a specific angle projected onto this line or surface is not linearly related to the angle, so dividing the total like you do won't work.

 

[dibbler67]

This is how I calculated the width of the area used by TOP sight with "triangles", the picture should clarify my thoughts:

Let's imagine that you are a camera directly above a soldier, who is a single point in a 2D coordinate system. Soldiers horizontal FOV forms a triangle, which one angle is 91 degrees as the horizontal FOV in the game (phase 1 in the picture). If you draw a single line in the middle of the triangle, you get a right-angled triangle, which one angle is 45,5 degrees. From that you can calculate, that when triangle's bottom leg is 1x, then the other leg is ~1,02x (phase 2). So in practice, an object 1 meter away should be 1,02 meters wide to fill half of the horizontal width of the screen in the game.

TOP sight has 2,5 magnification, so the same object should fill same amount of screen when it's 2,5 times longer distance from the soldier. So now we can imagine a right-angled triangle with a bottom leg of 2,5x and the other leg same ~1,02x. So soldier's "half FOV" is 22,15 degrees (phase 3), and whole FOV is 44,3 when the same ~1,02x object fills a half of the screen.

Now we only have to calculate what is the width of the area seen from the TOP sight. When the FOV in that tank optic is 15 degrees, we again can make a right-angled triangle by drawing a line from the middle of it. So we get a right-angled triangle with one angle of 7,5 degrees. When the bottom leg is 2,5x (TOP sight magnification), the other leg is ~0,33x (phase 4).

Now what does that mean at the monitor? Well if ~1,02x is a half of monitor's width (960 pixels), then ~0,33 is 310,5 pixels, and that's only one half. So by that the aiming reticle should be 621 pixels wide (phase 5).

Things that worry me in these calculations are "did I calculate the problem in a right way" and "how those reticles are drawn on the screen". I've modded another game succesfully with these calculations, but the aiming reticles may be drawn in a different way in RO2.

And aaz, shouldn't you calculate the area covered by a reticle with the formula from the area of a circle? Pi times the square of the radius; πr^2

I think your math is correct, in fact I did the same thing just with trigonometry.

However, I didn't account for magnification because I assumed drawing the reticle on an already magnified image would remove the need. I think that's wrong though.

The reticle must be drawn as a circle within a square, but that's not such a big deal.

 

[Stiltzkin]

I have some old sources, i dont know if they may help, im just going to throw them in here (since some of the posted links are apparently broken anyway):

http://www.liberatedmanuals.com/TM-9-258.pdf
http://www.panzer-war.com/page37.html
https://archive.org/details/GermanTechnicalAidToJapan (theres a part about optics)
http://www.75thguards.com/ww2online/downloads/Zheriz_Ziess_Sight_Guide.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a345431.pdf
http://www.panzerworld.com/german-armor-optics

also
http://www.merriam-press.com/russiant34t-34mediumtanksttpreliminaryreportno20.aspx

http://www.tandfonline.com/doi/abs/10.1080/13518046.2015.998132?journalCode=fslv20&#preview (this is one of the engineers/mechanics who worked on tractor facs and he was also a tank platoon commander i dont think theres anything better on the soviet t34 and its optics).

since its so expensive and you will only get cheap access with a university account ill post it here
Once Again About the T-34

 

[mlespaul]

I did a small backup of few articles from mlespaul's blog when there were photos.
[url]http://s000.tinyupload.com/index.php?file_id=73703627677010876253[/URL]

If you need some reticle patterns just PM me, I have some drawnings

Hooray! I live on!

M

 

[morticore]

Do you want it back?