Could be this a bug?

[GI Adelscott]

The tanks are going up through the slope and when they are on the top they discover some german guys down in the grassland.

Their canons are aiming to the sky but they have no problem to smash the germans anyway...

Are the maximun and minimum elevations angles modelled?

[LemuelG]

No. I wish it were otherwise.

[Dark Knight]

Wait, so the tanks could aim at those soldiers in real life? I can't even picture the turret pointing that far down.

[stikkypixie]

Wait, so the tanks could aim at those soldiers in real life? I can't even picture the turret pointing that far down.

No, the game can't handle gun elevations (apparently it's a tricky AI issue than it would appear at first sight).

[c3k]

The "willing suspension of disbelief" (a term relating to the author-reader relationship with any fictional writing) means that the assumption is that the tank would make micro-adjustments to bring weapons to bear. These adjustments are beyond the ability of the TacAI (and possibly the terrain mesh) to replicate or model. The gun elevation limits are not modelled. In fact, in some cases the rounds will not leave the barrel as you'd expect (they leave the muzzle at an angle, rather than parallel). This is to account for all the adjustments a real tank could make which are beyond the player's/TacAI's/Terrain mesh's control or abilities.

An example would be a tank trying to increase its elevation beyond the trunnion limits driving up onto a curb (kerb for the UK), a handy rock or log.

For the picture shown, imagine that situation in real life. Could the Shermans "wiggle" in place to create a lower crest? Perhaps there's a subtle defile near that crest line.

It is a game engine limitation (right now).

Ken

[Sitting Duck]

"It is a game engine limitation (right now)."

For grins, what would be needed to model Upper Gun Elevation Limits (UGEL) and Lower Gun Elevation Limits (LGEL)?

Vehicle Data

Upper and Lower Gun Elevation Limits.

For AFVs with rotating turrets, would the LGEL vary as the turret swings around?

I presume this data is available with some research, but not tracked in the game.

Situation Data

Shooter Vehicle Attitude (pitch, yaw - probably derived from terrain data)

Shooter Vehicle Altitude

Target Altitude

Target Attitude (pitch, yaw - not strictly needed for this calc, but important for determining impact zone)

Target Distance

How much of this data is already tracked in the game?

Base line gun elevation can be determined from the Target Distance and difference between the altitude of the Shooter and Target. That part seems pretty simple.

Base line gun elevation would then need to be modified based on the Shooter attitude (pitch, yaw) - and perhaps for turret angle of the shooter. This part seems a lot less simple...consider.

Shooter Vehicle Attitude would probably have to be determined from the terrain ("lay of the land" so-to-speak, say 5% grade @ 90d) and further modified by position of the AFV on the terrain (are you behind the low wall, climbing the low wall or coming down off the low wall?)...and then Shooter Weapon orientation on the terrain (for turreted AFVs).

And probably more besides...

For my own part, I think I'd be OK just leaving this abstracted as it is.

[stikkypixie]

"It is a game engine limitation (right now)."

For grins, what would be needed to model Upper Gun Elevation Limits (UGEL) and Lower Gun Elevation Limits (LGEL)?

Apparently it's not the physical limitations that are hard to do, but the AI part of it. The AI must know what adjustments to make to make a shot possible if it was originally not possible and that's a whole can of worms.

[~Viajero]

I obviously do not know anything about the engine or how the AI works but afaik the left/right angle limitation seems properly modelled in SPG´s (no turrets) for example, which need to actually turn the vehicle if the target is beyond those set limits; so wouldn´t a vertical angle limitation follow a similar programming logic?

If the engine concludes the shot is not possible a quick fix pending a full IA remodelling could be that the vehicle should behave as if no ammo was left for example, no? (hopefully that logic tells the vehicle to at least move back or away from LoS etc). And that logic (no ammo behaviour) has already been built in I hope! It would then be up to the player to reposition based on his own judgment.

[stikkypixie]

I obviously do not know anything about the engine or how the AI works but afaik the left/right angle limitation seems properly modelled in SPG´s (no turrets) for example, which need to actually turn the vehicle if the target is beyond those set limits; so wouldn´t a vertical angle limitation follow a similar programming logic?

If the engine concludes the shot is not possible then the vehicle should behave as if no ammo was left for example, no? And that logic has already been built in.

I am speculating here of course, but rotating a SPG to shoot at something does not change the position of the SPG. To shoot at something that is too high, you would need to move the vehicle and that's when things become difficult. There are many exceptions that would have to be considered and which are not easy to do well.

[~Viajero]

I am speculating here of course, but rotating a SPG to shoot at something does not change the position of the SPG. To shoot at something that is too high, you would need to move the vehicle and that's when things become difficult. There are many exceptions that would have to be considered and which are not easy to do well.

I am not suggesting the vehicle actually had to change position or find a firing solution location, but simply establish if in its CURRENT position there is a shot possible at all or not based on horizontal and vertical angle limitations. If a shot is not possible but still in LoS of an enemy AFV recognized as a threat then proceed to "no ammo" logic and behaviour until either a shot is possible or LoS is broken (or the player gives a new order obviously).

An AI routine to find a firing solution position even if successfully implemented may indicate our vehicle to move to awkard positions whereby they are exposed or otherwise unwise anyways. I much rather leave that to the player to decide, and consequently leave the IA with a much more simpler "no ammo" or similar logic (TacAI withdrawal behaviour may be also good enough) that would not interfere much with the player´s original intent.

The vertical angle limitation would have to be shown when checking a Target LoS line to a potential target for the player to realize the issue (much in the same way "hull down" or "partial hull down" or "reverse slope" messages appear now), otherwise the player may never know why his tank was not firing though.

[stikkypixie]

I am not suggesting the vehicle actually had to change position, but simply establish if in its CURRENT position there is a shot possible at all or not based on horizontal and vertical angle limitations. If a shot is not possible but still in LoS of an enemy AFV recognized as a threat then proceed to "no ammo" logic and behaviour until either a shot is possible or LoS is broken (or the player gives a new order obviously).

If I recall correctly the argument against this is that it would frustrate players to no end. Imagine waiting a full minute before being able to have a tank shoot (+ GUI to represent this). There would be a lot of threads about tanks not shooting while it is *obvious* all they had to do was move 5m forward, etc...

It could probably be done, but then at the expense of something else. This is just a compromise. They same ones like not having friendly fire for small arms or the blast of tanks firing not stunning/hurting anyone nearby etc...

[~Viajero]

If I recall correctly the argument against this is that it would frustrate players to no end. Imagine waiting a full minute before being able to have a tank shoot (+ GUI to represent this). There would be a lot of threads about tanks not shooting while it is *obvious* all they had to do was move 5m forward, etc...

It could probably be done, but then at the expense of something else. This is just a compromise. They same ones like not having friendly fire for small arms or the blast of tanks firing not stunning/hurting anyone nearby etc...

As I edited in my post, asuming a vertical angle limitation had been implemented, then when tracing a Target LoS line from your vehicle or waypoint the message should appear so you know (same as "hull down" messages etc). I guess that a routine that checks vertical angle limitation based on estimated vehicle orientation at the way point would have to be added in this case.

During a replay obviously you may not find out, but tracing that Target LoS from a way point or from your vehicle in your next orders turn should confirm the issue. In Real Time, well, you should be able to check any time.

Anyways, it may seem from what you say the issue is not new and has been already discussed, if the final decission to allow the tank to shoot was taken as a compromise so be it!

[dieseltaylor]

They same ones like not having friendly fire for small arms

I have shot my men in the back with a HMG on fixed fire .....so ... and at 37 metres at that.

It does seem surprising that elevation is not considered. I would imagine in town fighting tanks with no restriction on elevation are going to be remarkably more effective than they ought. What was the situation in CMSF?

[Sgt Joch]

It does seem surprising that elevation is not considered. I would imagine in town fighting tanks with no restriction on elevation are going to be remarkably more effective than they ought. What was the situation in CMSF?

It has never been in the game, even going back to CMBO in 1999.

The fact that players never realized this shows how infrequently it comes up:

http://www.battlefront.com/community/showpost.php?p=1177104&postcount=14

[Lt Bull]

It does seem surprising that elevation is not considered.

When you get down to the nitty gritty of modelling tank gun elevation limits in a game like CMBN, it becomes apparent how "tricky" coding the TacAI could become, though not impossible.

It would mean the TacAI tankers would be faced with "trying to best solve" situations where they have LOS to a target but no LOF to the target.

They would solve this by some combination of moving

a) moving forward/backwards

rotating the chassis

c) rotating the turret

until a LOF solution is found. In reality it can actually be a "trial and error" process because it is hard to predict exactly HOW a patch of terrain will orientate the tanks chassis if a tank decides to move and/or rotate, especially if it is rocky type terrain.

You just need to play any first person tank sim (like Red Orchestra or even World of Tanks that do have elevation limits) to get first hand experience at just how "touchy"it can be to ensure your tank chassis is orientated such that it can train it's gun on a target. This becomes more of a problem when traversing or coming to rest on rough or undulating terrain.

Without it modelled in the game, tanks can find "hull down" firing positions that both give them LOS to the target and LOF to the target where in reality they would only have LOS to the target (assuming the commander has full vision horizontally and vertically).

The game already apparently seems to track the orientation of the tank chassis however (it is taken in to consideration when determining angle of incidence of incoming AP rounds I believe) so this could be leveraged.

Essentially the game would need to track three variables:

eg.

1. chassis heading

2. chassis pitch

3. chassis roll

and then code a way that the TacAI could intelligently

a) move forward/backwards

rotate the chassis

c) rotate the turret

until a solution combination of 1,2 and 3 allow it to get LOF on a target such that it's tactical position is not severely compromised. In most cases this would mean a solution that involves the LEAST amount of physical movement form its present spot.

[~Viajero]

And that is why I "feel" leaving actual positioning of AFV´s should be left up to the player.

Limit the AFV´s behavior to calculate if in its CURRENT position/orientation/roll situation if it can have LoF or not (including its vertical axis angle limitation though). If yes, fire, if not then an option would be to consider it to behave as under a "no ammo" or "AFV TacAI withdrawal" or equivalent behaviour (given there are other AFV´s or units identified as a threat that can not be shot at and no other targets have been assigned to the vehicle by the player), which should already be both there built in. As long as they dont fire but they do not remain there as sitting ducks either I d be happy. Leave it up to me to choose its new location next turn.

[dieseltaylor]

This is one of those problems which is more theoretical than actual. Not to say that it never comes up, but it doesn't come up nearly as frequently as one might think. That's because other factors have a natural dampening effect on the extremes.

The lack of elevation restrictions has been with CM since 1997 and will likely continue long into the future. The reason is that fixing the problem is extremely complicated and very involved from the user's standpoint. Because the problem doesn't come up too often we feel we can "get away" without spending the considerable time it would take to overcome. If it were a common experience we would trash a couple dozen other improvements and focus instead on getting elevation restrictions in. Given the choice between fixing this and putting in lots of other things people want... the choice is clear that we should not do the elevation restrictions.

Steve

I understand the argument but I did think the game was going for realism so it is a surprise thta the situation has not changed. As to "not a problem in the past" I think, given units could be somewhere within a 20 metre square, then allowances could be made.

The idea that I can take my tank down an alley and hit units fairly adjacent but x levels above seems a recipe for unusual happenings. Possibly there may be some sighting restrictions that will make this unlikely to happen in gameplay - and fear of AT assets will stop players being too aggressive.

In the example of the bocage hedge being breached it does seem a likely event for Normandy and more than a little rough on players who wait in belief tanks will be unsighted and vulnerable when going nose-up.