LOS / LOF problems

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[Barleyman]

Originally posted by Battlefront.com:

As I understand it LOS is drawn from the location of the unit spotting to the Action Spot of the unit that it is trying to target. So if the Bradley is mostly behind a building it doesn't get to spot something that is around the corner. However, LOF is exact so the enemy can "see" that portion of the Bradley that is poking out and take a shot at it even though the Bradley doesn't have LOS.

Hmm.

What's "location of the unit" exactly? Some arbitary point, center of mass or maybe model-specific point? Can there be more than 1 for vehicles?

Is the action spot tied to the UNIT or TERRAIN? In other words, when our bradley drives along the road, it carries it's own "action spot" with it or it moves from action point to action point that are static "hexes" on the map?

And for that bradley-behind-building example, LOF doesn't matter if you do not have LOS, yes? So for bad guys to shoot at the bradley they need to have LOS to it's "action point"? But after it's been spotted they can take shot at any point of the 3D object, even if they lose LOS to the action point?

[Martin Krejcirik]

AFAIK Action Spot = 8mx8m terrain tile (not sure if they are the same as tiles in the editor, probably not).

Location of the unit - I would assume for the LOF check, it would be the exact position of a gun. There could be more then one defined (1:1).

But what is it for the LOS check ? As I understand it, the LOS check is 'from the unit to the Action Spot', so is there 'point of eyes' defined for a unit, is it 1:1, 'center of unit' or something else?

EDIT: I've reread Steve's initial comments about AS's and there he states the LOS check is from (center of?) Action Spot to Action Spot.

So Steve, please, how exactly is LOS check (spotting) done, is it traced from center of a unit, from individual soldiers or from an Action Spot ?

[ August 16, 2007, 04:04 AM: Message edited by: Martin Krejcirik ]

[Thomm]

I guess the logical system would be:

If (LOS from action spot A to action spot B exists) then

__do some finer grained LOS check.

else

__no LOS, proceed with program.

Best regards,

Thomm

[SlowMotion]

I saw what AdamL wrote about recently. A MG was trying to shoot at a Humvee behind some trees. The map was totally flat.

When trying to target the vehicle, game showed "reverse slope". When pointing at ground below it or even further away it was possible to select area fire.

[Huntarr]

...alas I had to shelve CM:SF until the LOS and TacAI get addressed. 1.02 was actually more frustrating for WEGO then 1.01 due to the units reacting less.

[KNac]

Originally posted by metalbrew:

It got me wondering about whether the location of the vehicle's eyes matters in the equation.

I don't know how individual soldiers in squads/teams track LOS & LOF. But for vehicles it does matter A LOT where the vehicle is pointing it's optics devices (or if the commander is unbuttoned).

So in this particular example the Bradley shouldn't be able to fire at RPG as he doesn't know that he is there, even if there is LOS, is not watching aat the RPG team.

[Barleyman]

Would be nice to get final word on this to clear up how the simulation actually works.. Maybe duct tape Charles to a chair and make him drink decaf until he coughs up the details?

If LOS is indeed tied to some "action point" grid distributed on even 8x8 spaces, it'd be good to have on/off visual clue to that grid!

[yuvuphys]

What worries me about this setup is that I could find myself in a situation where my unit A has LOF to the enemy's unit B, but b/c of action spots doesn't have LOS to unit B, and thus can never target unit B. However, at the same time Unit B may have LOS and LOF to unit A. Is this possible, Steve?

[ August 17, 2007, 01:59 PM: Message edited by: yuvuphys ]

[Barleyman]

bump

How's that whitepaper coming along on how LOS actually works in CMx2 engine games?

[SlowMotion]

I'm bumping this to 1.03 times. Did this LOS white paper already pop up somewhere?

EDIT: maybe it's this?

http://www.battlefront.com/discuss/ultimatebb.php?ubb=get_topic;f=52;t=000964#000000

Many people, me included, still seem to be confused about how these LOS abstractions should work. When current LOS system has been fixed to work like it should what kind of abstraction problems should players just get used to?

Here's how things look in 1.03.

In first picture no unit is selected. Part of an Abrams tank hiding behind a building is well visible.

In second picture the place should be exactly the same, but now a T-62 tank has been selected. No Abrams anymore. Is this because the center of this US tank is not in LOS and is this how things are going to be?

[ September 02, 2007, 12:14 PM: Message edited by: SlowMotion ]

[Pete Wenman]

Just to add to the mix. I was playing around in the editor building tank scrapes.

Base level 20, berm 25, but despite this towering over the Abrams it could still fire out, and take incoming fire. If this is the same for crestlines, it will be a real problem when judging where to stop to stay out LOS, let alone judge a hull down posn.

You can see here the rock wall, and beyond the smoke from the just hit T72. Taken with Camera 1 posn

Not so good

Pete

[SlowMotion]

Noticed only later that my previous link is to LOS explanation written one year ago Well, people were asking exactly the same questions then. No idea which parts of the answers are still valid though.

[panzermartin]

Hmm, yeah, I'm still disappointed with LOS behaviour. I was playing the 1st campaign mission with 1.03 and had put an M1 tank behind the berm, not visible to anyone. Yet, it was knocked out most probably from what it seemed a bottom hull hit-if this is modelled anyway. A shell passed through the ground and hit it in the belly, while it was on the incline. Quite a lousy way to lose an Abrams. Los/Lof problems though reduced are certainly not eliminated with 1.03. Waiting for more improvement in this critical part of the game.

[flamingknives]

Slowmotion:

I think I can answer the vanishing Abrams one.

With borg spotting done away with, not all units see the same. No unit selected gives a composite picture of what all your units have spotted, selecting a unit only shows what that particular unit has spotted. Hence the T72 hasn't seen the Abrams, but one of your other units has.

[SlowMotion]

But how is it possible for that tank commander not to see it? The tank is maybe 200 meters away, totally flat map between the units and he is even looking at exactly the correct direction.

In other situations I've seen buttoned tanks spot people moving inside nearby buildings in few seconds. Here the T-62 commander has perfect LOS to the direction of Abrams, yet he doesn't spot it?

I guess I'll have try this scenario again and see if just waiting long enough causes the T-62 to see the Abrams.

[Mishga]

I find my troops approach a crest and get shot to pieces thru the top of the hill.

Conscript Militia armies are routed before they even see a US fire team as they try to reach a safe point to observe the reverse slope area.

[Barleyman]

Originally posted by SlowMotion:

But how is it possible for that tank commander not to see it? The tank is maybe 200 meters away, totally flat map between the units and he is even looking at exactly the correct direction.

Because of the "action spot" spotting mechanism. Commander does not have LOS to the action spot of the hex the tank is occupying even if part of the 3D model is visible.

That's why we're asking for visual cue to the action spots so we can determine when cover is cover is cover. Done correctly, such grid could double as a terrain-grid, you know..

[SlowMotion]

Originally posted by Barleyman:

Because of the "action spot" spotting mechanism. Commander does not have LOS to the action spot of the hex the tank is occupying even if part of the 3D model is visible.

In the one year old LOS thread I linked yesterday Battlefront wrote that an infantry squad could have soldiers in three action spots. From your answer I get the idea that a tank would occupy just one 8x8m action spot. I checked some tanks stats from Wikipedia and Abrams length should be almost 10 meters when gun is pointing forward. British Challenger2 would be 11.5 meters. Some late war WW2 tanks would be similarly over 8 meters long. So if tank spotting really uses just one action spot, that could be quite confusing to the player. Parts of the tank would be visible to him, yet the spotting would ignore everything outside tank's one action spot. I drew some examples here (that blue thing is the tank, white squares are action spots):

I think my earlier screen shots would be close to what happens in case 2. You can see this situation when looking from Abrams to T-62 that hasn't spotted anything yet.

Only Battlefront knows whether we're on right track.

[SgtMuhammed]

Funny, it reminds me of one of my biggest gripes when I was OPFOR at Hohenfels.

The M1s and M2s all had their MILES sensors on the turret. You might be able to see a third of the vehicle but still not be able to kill it because the "target" was out of LOS. Maybe CMSF is a MILES simulation.

[Mishga]

As it stands it's impossible to judge hull down positions. You get tank sniped thru the terrain. Even if your below turret down i.e the berm is higher than your top MG.

[sandy]

I think that the problems highlighted in this thread indicate just one more example of why, so far, and IMHO, CMSF seems to be a step backwards from CM1 in actual gameplay.

If these issues are bugs which can be fixed by patch 1.12, or whatever, all well and good.

My worry is that they may be the result of ill-chosen but fundamental design decisions...

I certainly never saw anything like this in many years of playing CM1

No comment by BF I note.

[SlowMotion]

One more, this time spotting friendly units.

I don't think there's much sense for me to post other 1.03 examples.

First a picture when no unit is selected.

A Stryker gunner whose Stryker has been destroyed has arrived near a Humvee that appears to be totally visible. Not behind any other units or buildings. My intention was to first tell the gunner to run close to this empty Humvee and then jump into the vehicle.

Then select this gunner and Humvee is no longer there. I can't order him to enter the vehicle that he can't see.

After I ordered this gunner to walk a path near the Humvee, then he finally spotted it. Maybe after 30 seconds or so.

[panzermartin]

In the last example, maybe he was shaken/rattled or something after abndoning the vehicle?

[Barleyman]

Originally posted by sandy:

My worry is that they may be the result of ill-chosen but fundamental design decisions...

Oh well. Obvious solution would be more fine-grained "action spot" grid. I suppose eye candy department is mostly sitting on the GPU.

I wonder what kind of performance hit we'd get with, say, 2x2 grid. That'd be 16x more data to shift and what with relative spotting..

As CMSF doesn't play nice with dual cores anyhow, I doubt they want to target this into too-high CPU segment..

I wouldn't mind occasional spotting weirdness as in CMBB head-of-the-pin spotting meant you had JSII jumping to sight when it was halfway from behind that barn. But shooting throught solid objects is bad. At least the much-vaunted ballistic modelling should "know" you cannot shoot trough ground even if LOS engine says you can see through sand..

Perhaps the best solution would be to run a more fine-grained LOS check between any two objects the "coarse" LOS code says can see each other. Cuts down on the CPU time as it was.