Possible reason behind some CTDs, campaign/ship selection lag, etc.

**Rhuarc** · 04-23-2009, 20:35

This is (well, it could be) a great game, but I get the feeling that the devs bit off a tad more than they could chew on this one. For the record, I never had major CTD problems, only minimal campaign lag, and no Steam troubles. I have enjoyed the immersion of the game for the most part and the great attention paid to graphic details, etc. The game is beautiful. Still, I have experienced many of the gameplay glitches and problems reported by others and have got into a number of screaming matches with my monitor. I think many people are talking way too much about the game being bugged, when in fact a lot of what is going on might have to do with design and implementation. Sometimes ideas seem great at first, but are hard as hell to implement successfully. Let me explain what I think I see going on:

Where oh where is the grid?
I read in the pre-release blurbs about many new 'features' in ETW. One thing that caught my eye was a statement by James Russell:
“The campaign map for example is treated in a completely different way, and is no longer based on Rome's grid system -- it's completely freeform.” (http://pc.ign.com/articles/866/866990p3.html).

Previous releases were based on an underlying grid (think game board hexagons) that marked out specific spaces where units could reside. This also gave the game an easy means to calculate movement since each unit could move X-number of grid paces on its turn, and only stop on a single free and open hex. With ETW, they apparently did away with this grid. While this is innovative and great in theory, I think this has caused many of the problems people (and the AI) are having on the Campaign map and in general.

Naval lag: The program now has to calculate movement range, without the pre-set grid, taking into consideration enemy zones of control, separate unit ranges, the coastline, etc. As a result, clicking on a stack of ships often results in a 10 sec. lag as the program sorts all this out. You will notice this particularly in narrow sea area (i.e. the English channel) where a whole lot of things have to be factored in. I also see this more with stacks that have different classes of ships, with presumably different movement ranges. RESULT: huge lag on selecting ships in many cases. If you wait long enough, it usually figures it out- or just crashes to the desktop if it can't. (sigh) For the record, selecting a city containing army units also seems to give a lag, but less than seen with ships. Why? Armies have a shorter movement range requiring the program to do less work figuring it out.

Trade Zones: Same issue? Ships can get stuck after merging or splitting fleets on trade zones, or just entering them sloppily. Trade zone is a tile in a sea of un-tiled space. I think ships get stuck on the 'event horizon' if you will, or just don't quite get into the zone, resulting in a unit ending in neither. I think it may be the player who doesn't quite click on the zone exactly leading to a unit that is stuck in limbo. I found that if you take extra special care when selecting ships and picking their target destinations (like the trade zone you want) you can avoid this problem.

Coastline Embarking/disembarking: Ever pulled your hair out trying to unload troops onto a coastline? Then having to resort to moving your ship around until it finds just the right angle to unload? I pretty much gave up trying to do this after a while and now only unload in ports. The cause is, I think, the same. Without a grid system, the program has to 'decide' if you are close enough to unload. It probably has to do with the percentage of facing pixels on your ship versus the coastline space, or some such thing. Ugh.

Armies: Most of my army glitches have again come from attempting to merge/unmerge units, or move them in or out of cities. You can't move a unit out of city and into a waiting stack with one click. Why? Same deal. Your trying to move from grid space (city) to un-gridded open terrain, and then into another unit. You have to move the unit out of the city (one action) and then merge with the other unit (second action) People have also reported repeatable CTDs when overflow unit recruitment with a general gets bumped to a waiting stack outside the city (sorry, can't find the post). This may be a case of units getting stuck again on the 'event horizon' between city and terrain. Just guessing here.

Battle Map: Would this complicate how the program determines battle terrain and deployment? Sure. It can't just load up the battle map for that grid- there is no grid- so it has to create one. Randomly? Based on what factors? Region default? I have observed little correlation between exact unit locale on the campaign and battle map, so it must use a more general 'typing' system. Heck, without a direct correlation between the campaign map and the battle map, the program might even have problems figuring out where to place the armies and reinforcements. Anybody noticed this? (yuk yuk)

AI Naval Transport: Yes, all this may be a contributing factor in the inability of the AI to transport troops via ships. (and to be clear, the problem in ETW is not about invasions per se, but transport of army units by sea) I really don't think this is an AI problem at all. We have all seen the AI determinedly moving stacks to the coast or into ports, in preparation for transport, but it is never able to get them onto it's ships. Why? While the human player can jiggle his ship around until he can get it in the right spot to load/unload his army, the AI cannot. If the AI ship is not 'just so' along the coast, invariably the unit will move to the coast and then just sit there. Also, the player workaround of loading/unloading in ports may also not be available for the AI. I don't know for sure, but the 3-step process to embark your army (1. move into port, 2. press button to embark, 3. select and transfer units onto ships) might be problematic for the AI-even if it doesn't actually press a button. If the program can't easily get units onto ships, what you get is no naval transport, no reinforcing of colonies, no invasions, and bunches of AI stacks intended for the New World or India, wandering around aimlessly because their path is essentially blocked.

Basically, I think the lack of an underlying grid system is the cause of many of the Campaign problems in ETW. This is not a bug so much as it is a very ambitious feature that hasn't quite been ironed out in terms of gameplay. In spite of all the ranting on these forums, it may not be 'bugged, sloppy programming' at the root of the problem, but a new approach that introduced some unforeseen headaches. This is why CA has not been able to fix some of these problems quickly. We're not talking about cleaning up a bit of mistyped code here, but trying to address problems from what is a core part of the campaign game design. I have every confidence that they will (or have in the forthcoming patch) solve these problems, but it may take more than one patch to make this the great game I know it can be.

But then again, this is all just idle speculation...

**Ordani** · 04-23-2009, 21:06

The permutations of the campaign map movement possibilities are simply not large enough for the number of units in question to be that big of a deal on a modern microprocessor. There is still a discrete Cartesian grid on the map (otherwise, how would they render it?), it's just not as rigid, and pathing hints and collision detection still work in fundamentally the same way. I can explain this in depth if you want, but I'm not going to type out a ten paragraph explanation if nobody reads it :>

You need to separate the visual representation of what's going on from how the campaign state engine looks at it. The path computations on the tactical battle map are hugely more complex over a more complex (mathematically) field, and yet happen in virtually real time for thousands of units simultaneously.

Most of the campaign map lag that I've seen looks to be caching related, or rather, the lack thereof.

**Rhuarc** · 04-23-2009, 22:57

I see what you are saying, and I, not having programmed the game, have no idea how the engine does what it does, but I can tell you what I am seeing. I would think that the battle map deals with a completely different set of problems, for which they have had several game releases to iron out, optimize, and improve. AFAIK, it’s unit rendering and the calculation of physics. There are obstacles, but no movement range, no zone of control, and no boundaries to figure out (e.g. coastlines). It could be a matter of optimization (or lack thereof) on the campaign map as you suggest, but I think the new design plays a part.

On the campaign map (and I was talking about unit selection lag, not the panning over the map lag), just selecting a stack of units gives you a lag, when all the program has to do is calculate and display the unit's range. Why? Probably because it also has to factor in 'no-go' zones like the coastline and enemy unit's zone of control in multiple locations within the unit's range.

Plus the lag is not uniform. I seem to get much more selection lag with multiple range unit stacks and in 'busy' areas than with one ship in the middle of the Atlantic. It has to be the interaction of the movement/zone of control range of various units, along with a ton of other constraints, that is causing this particular problem.

I think it is all more complicated that it would appear. Just look at the edges of your ship's movement range. You will see no evidence of any regular pattern, so the program has to figure it all out to he nth degree and then 'draw' that range or area of movement Add in a couple of coastlines and other ships and it all just takes time- or CTD. If the map was based on nice, regular hexagons, we would not have half as many problems.

**Ordani** · 04-24-2009, 00:15

Originally Posted by Rhuarc

On the campaign map (and I was talking about unit selection lag, not the panning over the map lag), just selecting a stack of units gives you a lag, when all the program has to do is calculate and display the unit's range. Why? Probably because it also has to factor in 'no-go' zones like the coastline and enemy unit's zone of control in multiple locations within the unit's range.

This specific lag occurs regardless of the complexity of movement areas, and is demonstratively not a path calculation lag since you can select a unit, suffer the lag, then modify the map field to your heart's content and re-select the unit and not have it -- my speculation is that it is doing something very silly rebuilding the unit descriptions, capabilities, card pictures, etc, that it must do at least once, but usually only once, per turn/load for every campaign-level unit group it operates on. You don't see this lag in battles because it's building it all during the loading screen and then handing it over to the tactical battle subsystem.

CA has always had a somewhat weird relational data description scheme that never rightly made sense to me, but I assume it has some benefit towards producing a static set of values and decision trees for the realtime tactical engine from the highly variable unit stats in the campaign. Pop open the pack editor and you can look at how it defines and relates various entries. It reminds me somewhat of the "high speed" databases you see in realtime control systems, which are designed around getting an answer in a predictable amount of time more than being globally efficient.

**mmk** · 04-24-2009, 13:16

Originally Posted by Rhuarc

But then again, this is all just idle speculation...

But convincing.

**PseRamesses** · 04-24-2009, 13:55

I must confess something guys:
I play around 30-35hrs/ week and I NEVER had one single CTD, no lag, nothing, seriously!

The game flows smooth as silk. I can´t be that my PC is the only one powerful enough to handle the game with ease or that I´m just lucky, can it?!

Or can it have something to do with handling in some cases? I´ve seen some of my avid game-friends clicking away like madmen, fast and almost furious, just to get to the next stage. Me, I just take my time.

Sure, I recognize the silly little things like not being able to move a unit from a town directly into a stack but I just place the stack one "tile" away and now I don´t even think about doing it. I always load and unload in ports, when I can, since the units movementpoints are untouched throughout the seavoyage. I also move my existing indiaman out of the tradeslot before adding or removing anyone. This also happens by habit.

**SpencerH** · 04-24-2009, 18:28

Originally Posted by Rhuarc

Let me explain what I think I see going on:

But then again, this is all just idle speculation...

An interesting hypothesis. It's well known that the freeform pathfinding AI for the CIV games ate up a huge amount of RAM and caused the lags and crashes for slower PC's.