Thanks for your tutorials!
One thing about the ladder sights / animated iron sights - you say in your first video on the subject that the bullet will hit the center of the screen at the zeroed distance (if aiming horizontally). That's what happens normally where the game adjusts the initial angle of the bullet automatically, but if you go the route of (animated) multi-eye sights that goes out the window. As a result, the weapon you show in the video starts to get really inaccurate by 700m (it's not your eyes, the bullet just wasn't going where you aimed).
The initial bullet angle required is still the same, but now the player has to apply it manually, and the mod author has to help with that, by placing the cameraDir and discreteDistanceCameraPoint[]s so that the front post and eye mempoints line up with the bullet's trajectory at each distance. In order for the aim to be accurate, rather than animating first and placing eye mempoints where they look good - you need to first place eye mempoints accurately, and then animate the rear sights so they look good.
Step by step, this means:
1. Decide on and stick to an airFriction and magazine/weapon initSpeed. Once you're done, any change to the bullet's trajectory will throw off the aim. Keep in mind ACE overwrites airFriction and adds Advanced Ballistics values to vanilla ammo, which will change the trajectory.
2. Place your cameraDir mempoint on the front sight.
3. Place the discreteDistanceCameraPoint[] mempoints so that the bullets hit where you want them, by trial and error. If the bullet goes low, heighten the eye, and vice versa. Or theoretically, I suppose you could calculate their proper positions. Ruthberg's VR training course helps, as does setting something like opticsZoomMin = 0.25/25; and dispersion = 0.0001; during testing. Zeroing a PKM 100-1500m like this took me an evening.
4. Now you can animate the rear sights. Again, probably through trial and error, to line them up at the right height or angle so it looks good. This took me another evening.
I found NIArms RPK12 a useful case study ( hlc_rifle_rpk12 ) with config, p3d, and model.cfg all available. In particular, how the RPK's stepped animation is set up can be seen here (search for Range_100_rot ).
I just recently did this for a PKM, and thought I'd write down my lessons learned - if nothing else, in case I need to do it again. Your videos were one of few sources that directly spoke about this, so I thought I'd post it here.
Edit: Oof. Currently, rather than fall back to Arma 3 ballistics, if ACE AB is enabled it assigns some default values if its variables aren't found, meaning if you care about ACE compatibility you can't just leave AB variables undefined. If you have a look at ACE's ammo though, their airFriction and ACE AB variables should result in trajectories that are in the right ballpark of each other. With only a little experimentation on the ACE_ballisticCoefficients[] variable, I got a good result that matched up with my eye points.
