[WIP] Optical Targeting Assist, with Omnimeter

[CapnScurvy]

This modification is intended to correct the optical view of targets through the various scopes, enabling a correct reading of height/length dimensions when using the Telemeter markings (the vertical and horizontal hash marks in the scope). This will aid in correct range and angle on bow determinations when using these Telemeter scope marks. An in-game tool called an Omnimeter will be used to help facilitate these findings. Corrected mast heights and added ship length dimensions will be placed in the recognition manual to aid in this process.

The basis of information which I have used for the majority of my reference comes from a once confidential instructional pamphlet entitled Submarine Torpedo Fire Control Manual found HERE. It was published in 1950 at a time when the WWII fleet boats were still used as the main ship of the line submarine. Although the whole manual is interesting, Chapter 5 holds the most information on the specific periscope characteristics and the process of turning a targets height/length through Telemeter readings into range and AoB findings. I do admit some of the measurements do not add up when correctly figuring the formulas. For instance on page 5-3 it states We know that at a range of 1000 yards, 17 ½ yards, or 52.5 feet will subtend an angle of 1 degree. To be exact, 1 degree of angle at 1000 yards distance is 52.356 feet. Also, the correct range formula for the Hi Power magnification should read 76.4 not 76.2 (4 x's 19.1= 76.4). Small issues but whoever proof read these manuals should have done a bit better in what they cleared for print. The basic process is correctly laid out, so the information is accurate when using the corrected math formulas.


The overall process of making the modification is to have a working Omnimeter for in-game use, then correcting the optics (scope game views) so an accurate measurement can be obtained with the tool. Next, each ship will have a corrected lead mast head height and ship length dimension added to the Recognition Manual to aid in the two equations of finding target range and angle on bow. The goal is to give a Manual Targeting player the ability to use tools that were authentic and that will help in these determinations.


Omnimeter

A while back I posted images of a working circular Omnimeter (my first attempt) which did indeed work, but at a slight disruption to the in-game functions of the other dials it was linked to. I wasn't entirely happy with the fact that movement of one of the two dials of the Omnimeter also moved the torpedo spread dial. This wasn't too terrible since a good captain would check this dial when setting up the shot and reset it to what he intended. However, I wanted to try and make a tool that resembled the original and would cause a bit less trouble when manipulated. Since modded in-game devices need to be linked in some way to existing game devices I decided a less intrusive process is to have it linked to a little used game tool (the opacity slider of the message box). This allows for a more authentic Omnimeter with fewer disturbances to other game entities.

Below is an image of an Omnimeter that was constructed for the crew of the U.S.S. Cod. You will find a similar device (but not exactly alike) in the Torpedo Fire Control Manual. There was no manufacture that made them, rather the crew usually came up with their own version.






This is my in-game version.





It is moved about the screen using the message box's capture/drag device. Each slider is independent of the other for correct use. There are a couple of issues with its use. When at the Command Room screen the device seems to want to lock up the mouse when dragging the sliders after a bit of use. The correction is to jump to another station (the Navigation Map or one of the other Periscope stations) and the mouse will return to normal. This will only occur when at the Command Room screen!! Since the only time one will use the Omnimeter is when you're at one of the scope stations (Observation, Attack, and TBT) this really isn't much of a concern. Just keep in mind the correction if you drag up the tool and manipulate the sliders when you're in the Command Room. The second problem is to have the tool lost at the bottom of the screen if you drag it and the message box completely out of sight. The bottom of the screen will not allow you to retrieve the device if the message box is completely gone. The only fix for this is to restart the game from a windows execution. This really isn't too big a problem either since the stock game allows this behavior. Try it, the stock message box will not return if you drag it out of sight at the bottom of the screen and release the mouse capture. Just another game quirk we all live with.


Game Optics

So, the in-game Omnimeter is completed and works well. The next issue is to correct the optics. You may ask, what's wrong with the optics? Well for starters the "magnification" and field of view of the stock game are incorrect. The Submarine Torpedo Fire Control Manual states on page 5-1, the magnification for the Type II (Observation scope) should be:

High Power 6.0x
Low Power 1.5x

The Type IV (Attack scope) has the same power.


The stock game optics gives us a magnification of:

High Power 4.0x
Low Power 1.0x

Its little wonder the game seemed to have the ships farther away than they should be. I made a modification (Ship Centered, Accuracy Fix or SCAF for short) to help allow a player to use a more visible part of a ship (funnels, flag tops) to measure with the stadimeter because the mast tops were not visible (least what I thought) at normal range finding distances. Having the magnification corrected will allow for a clearer view of the mast top. It's my plan to have all corrected heights return to the main or tallest mast head with this mod. If we can see them better, then lets use them!

To correct the field of view we need to look at the stock view and what it shows. The following image is taken with several stationary ships set in front of a stationary sub. The Akita (at the relative bearing of zero) is 1000 yards away. The range isn't really important, (neither are the other ship distances) but what is important is the field of view between the scopes left and right outer edges. The first image shows the Akita at a relative bearing of 0, using the Low Power magnification. I've drawn a red line on the right hand side to point out the area on the ship we will use to mark the outer right hand field of view position. This point on the stationary adjacent ship has to be used, open water doesn't leave you with much of a reference point. It's just about centered on the super structure of the freighter





The next image has us moving the scope to the right, placing the center cross hair on the point we referenced.





Reading the relative bearing of the stock game, the outer FoV is approximately 20 degrees from center. When you add the left side, the total FoV is approximately 40 degrees. On page 5-2 of the Submarine Torpedo Fire Control Manual you will see the true field of view should be 32 degrees. Were off by a total of 8 degrees at Low Power. So, how does this translate to feet? One degree at 1000 yards is equal to 52.356 feet. Times 8=418.8 feet off!! You move out to a range of 2000 yards and yes, the error doubles.

While we're in the manual, a High Power magnification true field of view should be 8 degrees. So, let's see what we have.

The following image has the same grouping of ships, this time with the center reference point to the left bow of the Akita at the 355 relative bearing. Notice the right hand edge of the view is marked at a point on the Akita behind the super structure of the ship.





The next image below shows this same reference point centered with the cross hair and now the relative bearing reads approximately 0 degree, a 5 degree difference. This means at High Power the stock game has a total FoV of 10 degrees from left edge to right edge, where it should read 8.





Without doing a lot of head scratching we can see the stock game needs to be corrected if we want to compare apples to apples and determine what really are we looking at through the games inaccurate eye. Count the Telemeter divisions of the scope, either horizontally or vertically there are 32 divisions. The game dev's planned to have a correct 32 degree FoV but they failed to input the correct "camera" parameters to make the correct view size. It's understandable why there was so little amount of reference in the game manual about the Telemeter marks. They really don't work when trying to use it as described. Not only is the magnification off but the FoV is too great for what the scope should be. I realize the stock relative bearing compass is very forgiving considering its small size, it only as a mark every 5 degrees. Lot's of room to have a couple of degree error, and no one to be the wiser. So, the mod will be using a much larger and more accurate compass in the future. It's made by Captain Cox (an oldie but a goodie). In my next post I'll be showing you what a corrected view of the world will look like (surprisingly, it's not too far off from what my MaxOptics IV modifications would give you, but I'm not here to talk about that. We've got bigger fish to fry).

More later.