no tree collision?

[9.JG27 DavidRed]

hey guys, im new to this forum and new to DCS.today i bought the P51(german disc version)

first thing i can say, although i played 1946 and Cliffs of Dover, im really impressed by the complexity and details of the cockpits....its the first time that i actually feel to fly a sim more than a game to be honest....

 

one thing i noticed, is that in my game currently, i can fly through trees without colliding...

i looked into the settings, and set everything to "sim" mode, but im not sure which setting i have to change to get collideable trees....or do trees dont have a collision model just like in CLOD?

thats the first question i have, but be assured there are more to come!

thx in advance.

btw, ED,....make a 109 or 190!:)

[159th_Viper]

Welcome :)

 

At present trees do indeed not have a collision-model due to a SIM-engine-limitation. They could, but that would mean that a helluva lot else will go down the crapper so it's no collisions at present.

 

There is however a 3rd-party Dev working on a terrain-pack that includes collision-models for forests etc etc but I cannot comment on the extent of the work except in the broadest possible terms.

[9.JG27 DavidRed]

Thx for your answer viper...

coming from clod, i can live with that.

[maturin]

If a 3rd Party dev can fix it, ED should be ashamed for not doing so themselves.

 

As if crude selective collision boxes aren't ancient technology.

[NineLine]

If a 3rd Party dev can fix it, ED should be ashamed for not doing so themselves.

 

As if crude selective collision boxes aren't ancient technology.

 

I dont think its a matter of they cant do it so much as the performance cost with the older terrain engine, maybe this will be fixed in EDGE, but I dont think they have commented on it yet. That said CloD left them out for the same reasoning I believe... the performance hit on such a large scale area. I would image the 3rd Party dev working on it will run into these performance hits as well.

[SkateZilla]

i figured that out when flying through them kicked me from MP and the logs says tree_1 (though 9 or so)_blk has invalid bounding box.

[NineLine]

Wonder how using a trigger zone would work... obviously there arent too many round forest areas, but maybe something could be done by missions builders for certain parts of their area of operation with trees....

[maturin]

I know that performance is an issue, but it doesn't need to be. The engine shouldn't even need to track trees as objects.

 

Source Engine has volumetric triggerzones that are just polygons with xyz coordinates. It can't be too hard to make forests generate their own custom-sized trigger zones that collide only planes and (possibly) missiles. The engine already has to draw these forest shapes on your map, and a complementing trigger zone would simply be that shape applied along the ground surface with a uniform height value, somewhere a meter or so below the highest trunks.

 

For windbreak trees along roads, they could have built the maps with long linear rows of trees that have their own 2D trigger zones attached. And none of this geometry needs to matter in the engine except when each player's plane is near a forest object. One player and a few of his missiles, keeping track of one object, only in close proximity.

 

There are obvious limitations by which individual trees in town detail zones would be left out, and the collision would not be perfect. Dip your wing into the collision zones or fly between two trees, and you will die, but real forests are denser and have branches that go unnoticed. And vehicles could drive through perfectly well. But it's not that hard or resource intensive this way. It could have been done from the start, and now it might be too late.

[Kuky]

Unless you've tried it you wouldn't know if and how hard it is or would be

 

And you can't think two objects (missile/aircraft and tree(s)) to keep track when in close proximity only... their position needs to be know all the time in order to determine if they are in close proximity or not and that means practically hundreds of thousands of extra objects (trees) needing to be tracked at all times.

Edited November 30, 2012 by Kuky

[Nate--IRL--]

Nothing to do with performance IIRC, It just Borks various unrelated aspects of the AI IIRC, As well as causing a few other issues that seemingly have nothing to do with trees or AI.

 

In other words it can be done, it just breaks too many things for it to be a priority.

 

Nate

[maturin]

Unless you've tried it you wouldn't know if and how hard it is or would be

 

And you can't think two objects (missile/aircraft and tree(s)) to keep track when in close proximity only... their position needs to be know all the time in order to determine if they are in close proximity or not and that means practically hundreds of thousands of extra objects (trees) needing to be tracked at all times.

You would just tie the distance tracking to the rendering of the actual trees. When the GPU says it's time to draw the green stuff, the distance script kicks in.

Since most people have trees invisible out past a few kilometers, and each forest would be one object, that's a performance hit of roughly zilch. Like three objects, and the distance measurement wouldn't even need to be remotely accurate (contrast this to the hundreds of weapons and flight control variables that actually slow down your CPU), since precision only matters when you are very close to one particular object.

 

It just Borks various unrelated aspects of the AI IIRC, As well as causing a few other issues that seemingly have nothing to do with trees or AI.

I think we're all willing to accept a lot of limitations and workarounds in order to at least get a working prototype. Who cares if AI fly through a tree every now and then? 'A few other issues' is something that a patch should deal with, and if a tree solution can prevent ground units from looking through foliage, it will resolve a truly existential threat to the gameplay of both Black Shark and Combined Arms.

 

In my opinion, that's a priority.

Edited November 30, 2012 by maturin

[Wolf Rider]

I dont think its a matter of they cant do it so much as the performance cost with the older terrain engine, maybe this will be fixed in EDGE, but I dont think they have commented on it yet. That said CloD left them out for the same reasoning I believe... the performance hit on such a large scale area. I would image the 3rd Party dev working on it will run into these performance hits as well.

 

 

Question, in general...

 

The towns/ villages/ etc in current DCS have collision boxes contained in them, eh?

[maturin]

You can crash into buildings, if that's what you're asking. But there are a lot more trees than buildings, and they have more complex geometry.

[sobek]

Since most people have trees invisible out past a few kilometers, and each forest would be one object, that's a performance hit of roughly zilch.

 

It was already stated that one collision box per forest is not feasible.

[maturin]

It was already stated that one collision box per forest is not feasible.

Uh, where?

 

I mentioned that a large part of the idea is retroactive. It would be hard to retrofit hundreds of forest polygons with collision boxes (of the sort that exist as astoundingly simplistic and performance-efficient features of other engines) NOW. But the decision not to implement something like that in the beginning was a mind-boggling oversight, not an unavoidable tech limitation. Maybe it would have required a hit in graphics quality and nice reflecting water and heat blur on afterburners. But this is a sim, damnit, and essential gameplay realism comes before eyecandy.

 

Then again, currently ED managed to design an autocannon that requires a 64 bit system, so should I be surprised?

[Weta43]

You would just tie the distance tracking to the rendering of the actual trees. When the GPU says it's time to draw the green stuff, the distance script kicks in.

No you can't, not in the current engine, it wasn't designed to allow that.

 

Since most people have trees invisible out past a few kilometers,

I think the fact that you have trees invisible past a few kilometers is not proof that most people do (As you've said elsewhere, your machine is below minimum recomended spec).

 

Uh, where?

In the post you quoted :

It just Borks various unrelated aspects of the AI IIRC, As well as causing a few other issues that seemingly have nothing to do with trees or AI.

 

But the decision not to implement something like that in the beginning was a mind-boggling oversight, not an unavoidable tech limitation. Maybe it would have required a hit in graphics quality and nice reflecting water and heat blur on afterburners. But this is a sim, damnit, and essential gameplay realism comes before eyecandy.

The engine was built primarily to allow A2A combat. It's not immersion killing if trees are non-collidable while you're flying at 500m, 1, 2, 5 or 10km.

It does kill immersion if while flying at 0.5, 1, 2, 5 or 10km there are no trees to be seen or they're all doing nasty pop-up under your plane.

(The heat blur and reflections comments are spurious - both could be turned off or down until very recently & so there was no trade off to be made (water less so now, now that even cheap video cards can deal with reflections))

 

If the plan had been to make a ground war engine - or even a dedicated mud-mover engine, I might agree with you, but that's not what happened.

[maturin]

No you can't, not in the current engine, it wasn't designed to allow that.

The engine can't run scripts? It can't check, for example, proximity to an object given conditions such as altitude? Distance-checking a certain object class within 2km whenever a plane drops below 500m of altitude is the sort of thing a two-bit Arma modder could do in their sleep. This would function regardless of whether the game was drawing the trees or not.

 

I think the fact that you have trees invisible past a few kilometers is not proof that most people do (As you've said elsewhere, your machine is below minimum recomended spec).

If your computer can draw thousands of trees out to many kilometers, it should also be able to track the distance to some of those forests, no? I was addressing the issue of users who don't draw the trees at all, and don't see what they are about to collide into. I can draw forest with a below-min reqs laptop, without immersion-killing pop-up, therefore a minimum draw distance for trees would be forced as part of any collision fix.

 

It just Borks various unrelated aspects of the AI IIRC, As well as causing a few other issues that seemingly have nothing to do with trees or AI.

No mention of collision boxes or workaround solutions there. The AI issues could be fixed by making forest invisible to AI, leaving it for players to worry about. ED seems to like fixing things later, so we should let them do that, so long as there's some progress. "Causing a few issues" is vague and sounds so trivial. Presumably they tried the most logical solution of making tree models collide, found a bunch of issues and then dropped the matter. The post proves that it's not impossible, just too much work to accomplish based on design priorities that are, in my opinion, FUBAR.

 

As for the engine design and A2A combat at altitudes... Black Shark was FOUR YEARS AGO. A temperamental engine with hush-hush 64 bit requirements and tons of CTDs can be tolerated in the name of a good game, but is just hasn't been adapted to the needs of two ground attack modules, a low-level dogfighter, and now CA.

[Wolf Rider]

You can crash into buildings, if that's what you're asking. But there are a lot more trees than buildings, and they have more complex geometry.

 

Is that what is causing the FPS drops looking around towns/ airports?

 

True that trees are far more complex than buildings and painful (in many ways) to design a collision box for each and every tree, all polygons accurately included. Is it viable to have just a spike/ thin tall cylinder 'box' placed in the forest at (say) arbitrary figure of spacings with random placement? ('cause all that really is needed is just basically a trigger, which also allows ground units to do their thing whilst also being inhibited by forest)

[maturin]

True that trees are far more complex than buildings and painful (in many ways) to design a collision box for each and every tree, all polygons accurately included. Is it viable to have just a spike/ thin tall cylinder 'box' placed in the forest at (say) arbitrary figure of spacings with random placement? ('cause all that really is needed is just basically a trigger, which also allows ground units to do their thing whilst also being inhibited by forest)

I would be overjoyed to simple have a 2D line segment giving collision to each trunk. Or a volumetric collsion box that is essentially cylindrical for large groups trees or even entire forests. And let tanks drive through trees with a speed penalty in forested areas; CA is already 75% abstraction.

[Wolf Rider]

no, no, no :) ... to 'each trunk' is not needed and complicates things immensely. just triggers placed very so often and randomly (important would be no pattern to pick) a big box around the entire forest makes it worse - totally unfeasible.

[maturin]

no, no, no :) ... to 'each trunk' is not needed and complicates things immensely. just triggers placed very so often and randomly (important would be no pattern to pick) a big box around the entire forest makes it worse - totally unfeasible.

A box would probably be too hard to retrofit (although simplicity itself to implement if designed from the outset). A simple ground hugging layer would be easier. You would probably be able to fly underneath when entering a forest from the side, but you would just die on the ascent.

[Weta43]

The engine can't run scripts

Actually, until very recently, no it couldn't.

 

On the whole, it seems you made some reasonable suggestions to an acknowledged problem, and have had people explain why these suggestions have not been used historically.

From there I think you have a choice between believing one of three things.

 

Either:

1 / E.D. and the entire modding community for the last 14 years* have collectvely, willfuly and deliberately decided that no-one would create a workable mod or update that both gave collidable trees, and didn't introduce other, more annoying and immersion killing, problems.

Or

2/ It's not as easy as you think (the ideas you've suggested have been thought of and tried before, found wanting and that's why people are telling you so in their posts), and the most appropriate way to tackle the engine's issues around ground warfare is to design a new engine from scratch (which is well into development now).

Or

3/ None of the approaches you've suggested were ever considered by either E.D. or anyone in the community over the same 14 years.

 

I feel like you're leaning towards "1" (or maybe "3")

 

{* The current engine being an evolution of the Flanker engine, which dates to the late 90's)

Edited December 2, 2012 by Weta43

[maturin]

I very much believe that the solution is too complex to be attempted by a modder.

 

It seems likely that ED has lacked the time, resources, but also the will and proper design priorities to exhaust every possible approach to the problem.

 

Oh boo-hoo, it caused some AI problems and other issues. So fix them!

 

ED's decisions get a lot of flak in many respects, so it is not unfounded to suspect them of poor performance here. I accept their difficulties with finances and technology access, and not part of the annoying crowd that expects clickable 6 DOF cockpits for every flying machine in existence, but this is one failure that deserves criticism.

 

But yeah, can't wait for the new engine. I hope the wait is worth it, if it's prevented them from releasing a more short-term solution.

Edited December 2, 2012 by maturin

[Weta43]

But yeah, can't wait for the new engine. I hope the wait is worth it, if it's prevented them from releasing a more short-term solution.

We live in hope :)

[Eihort]

and the most appropriate way to tackle the engine's issues around ground warfare is to design a new engine from scratch (which is well into development now).

 

Wait. Wut?