An unexpected way to generate growth

[z]

Did you ever spend weeks or months creating just the urban region you wanted, watching it grow from small towns measuring in the thousands to large cities with populations over a million?   

And did you take loving care of all these cities, making sure all your Sims were well educated and had good health care, and had good fire and police coverage?  And did you give them good parks, and place the high density zones near the parks and water? 

And did you balance your zones so there were enough jobs for your Sims, and demand for everything was always positive? 

And did you watch with pride as first small multi-storey buildings arose, eventually followed all the way up to Stage 15 skyscrapers in your big cities? 

And then one day, did growth level off and stop for some unknown reason, even though demand remained unchanged?   

And you checked everything, and education was right near 200, life expectancy was almost 100, and (through backbreaking efforts) pollution was almost nonexistent in most areas?   

And your traffic was flowing well, with no major problems?  And your power and water was sufficient?  And your garbage was being taken care of properly?  But still, nothing new would grow?   

So you waited years, then decades, then centuries, AND STILL THERE WAS STILL NO NEW GROWTH?   

Did you ever have this happen to you?  Didja, buddy, DIDJA?   

Well, fret no more!      Now, with a few clicks of your mouse in one of your high density zones, you can start a new skyscraper growing in the are of your choice, just within a few days, or a couple of months, max!     A few more clicks, and another skyscraper or two!    Or, you can temporarily stop the simulator, spend a few minutes work (yes, just a few minutes, my friends, just a few minutes), and when you restart the simulator, a whole area of high-rise construction will erupt into life, the likes of which you have never seen!     Residences for tens of thousands of additional Sims will be created!  Or tens of thousands of new jobs!  Or both!  And it all happens wherever you want.   

So how is this done?  Well, I assure you there are no cheats involved.     No sir, no ma'am, this is an honest game.      No extra plugins needed, either.  We just use a very obscure property of the simulator to do this.  Want to know more?  Step inside, step inside...

[/barker's spiel]

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Like many useful discoveries, this one started out somewhat by accident.  I was working on traffic problems, and I had figured out that one of the sources of traffic problems for me, and probably a great many other people, was MT stations with capacities that were too small.  (For my full explanation of what I found here, and why I decided this, check out my posts in Cogeo's Transportation Lots.  What's most relevant here is that I found, not surprisingly, that replacing a congested station with a higher capacity station that was not congested often eased traffic problems around the station.  Nothing surprising here.  But what was somewhat unexpected was that I noticed when I did this, I often got additional building growth near the station as well.  OK, I thought, maybe that's a result of the traffic's flowing better.  But more experimentation showed it was not that at all.  If I plopped a new MT station in a high density area where traffic flow was fine but there had been no growth for a long time, sometimes centuries, typically I would get one or two new buildings to upgrade.  The upgrades happened anywhere from immediately to within a couple of months, and did not require the traffic simulator to run before they happened.  The new buildings always sprouted within a one-block radius of the new station, or about ten squares.  Within that radius, the location of the new building was quite random; it was just as likely to grow at the edge of the radius as it was right next to the new station.  But there was also a definite cutoff point; the new building would never grow 20 squares away from the new station, for example.

And as I implied above, if I stopped the simulator and plopped a large number of new MT stations over a given area, when I restarted the simulator, there was what appeared to be a strictly additive effect, and buildings would immediately start growing all over the area I had plopped.  Never anywhere else, though.

Further experiments yielded more information.  This effect has nothing to do with the traffic simulator, because it happens even in areas where there is no traffic at all.  A case in point is my downtown Chicago tile, where at 1.8 million, the commercial jobs outnumber the residents almost 3 to 1.  However, I would estimate that about a million of those jobs currently are not filled.  In the core of the downtown area, there are skyscrapers back to back, none deteriorated, none abandoned.  Yet as has been noticed elsewhere, the two numbers for occupancy that show up in a normal query are not potential occupancy and actual occupancy; they are both different types of potential occupancy.  To get the true occupancy, you need to use the route query tool, and find out how many workers work at the building.  It turns out that at most of these beautiful downtown skyscrapers, there are no workers.  Zero.  There's no traffic of any kind through the heart of downtown, either, which is consistent.  Yet the buildings all stay shiny and new, because demand for all commercial types is literally sky high.  I think this situation has something to do with the CAM demand bug; I'll find out in CAM 1.1.

The reason for describing this situation in so much detail is so that the significance of my next findings can be understood.  When I started plopping additional MT stations downtown, where there was no traffic and the existing MT stations had zero usage, new buildings started growing in exactly the same way as in other zones.  So that's why I say this has nothing to do with the traffic simulator; in this case, there was no traffic for the simulator to work with, either before or after I added the new stations.

I also discovered that high demand is not required for this effect to occur; demand need only be positive.  Nor is the effect proportional to demand.

For most of these experiment's I used cogeo's RTMT stations (although with increased capacity, as explained in the link to his thread referenced above).  However, I verified that this effect works in just the same way if you use non-RTMT stations.  It's just a lot harder to plop a bunch of them down in an area that's already been developed.  (BTW, I know a lot of people don't like to use RTMT stations because of their perceived effect on the traffic simulator; I had an interesting discussion with jplumbley where I disputed this point based on my experience; you can find this discussion in TE Lots, Transit Switches, and You.)

So what's happening here?  I think at this point I have enough data to answer this question.  When the simulator runs, it repeatedly has to decide whether to upgrade existing buildings, or in the case of empty lots (where this effect also works), whether to build a building at all.  As everybody knows, many, many factors go into this decision.  I seem to have discovered a factor that has been unknown until now; at least I haven't seen any mention of it.  Apparently, the simulator takes into account what the MT station capacity is within a radius of about ten squares of the building.  I have also verified that it's capacity and not number of stations that counts, as replacing stations with stations of higher capacity will trigger this effect.  The effect will happen in lower density zones, but at a much reduced rate, probably because of the ceiling on building size in these zones.

After the new buildings have been erected, they behave quite normally.  There is no population crash after a few years or a few decades, as long as you keep your residents and jobs in balance.  By now, I have added hundreds of thousands of residents and jobs to my cities this way, and the results are stable over long periods of time.  And these buildings are not immune from the rules that govern other buildings; if you use this method to build residences in areas where residences typically become abandoned quickly, your new buildings will becaome abandoned quickly as well.

Why does this effect happen?  My guess is that Maxis intended nearby station capacity to have a minor effect in determining when buildings were constructed or upgraded.  With CAM, capacities of many MT stations have increased drastically.  The original Maxis formulae did not anticipate this, and as a result, station capacity now has an inordinate influence on building construction.  Of course, it may work the other way around as well, which is the point of this post.  If you're building a city where you want a lot of skyscrapers, you will need plenty of MT stations of appropriate capacity, even aside from your traffic needs.  I'm not sure what the other implications for CAM are, so I'll let the experts ruminate on this.  In the mean time, have fun building your cities!   

[FrankU]

This is very interesting.
It must have been a lot of work to find this out. Great research!

It also stresses one of the probably most famous sayings in SC4: "Plop MT stations. If you think you have enough, plop some more."

[CasperVg]

I think it works with all sorts of mass transit, because the CAM limits growth when it thinks your transit system will not be adequate for the new growth, I think.

[xxdita]

Actually, this was all taken into consideration as I tested the new NAM traffic simulators months ago. With CAM, there does seem to be what I call "an artificial cap" involving transit. Technically, it's the desirability of a particular parcel of land that is effected directly by the distance and capacities of the servicing transit networks. Even if the desirability map shows entirely green, other factors come into play when the simulator chooses what stage building to grow.
Buildings can only downgrade by wealth, or by becoming abandoned completely. There's no way for the game to grow a Stage 4 where a Stage 12 building already exists. The building must be demolished in order for anything of a lower stage to grow.
CAM actually prohibits unsustainable growth as much as possible, with added desirability requirements. You'll see a similar boost by replacing streets with roads, and roads with avenues, but a solid mass transit system is the absolute best way to insure growth in a CAM Metropolis.

[z]

So it's CAM that's causing this behavior!  What you describe is completely consistent with what I've noticed.  I've also noticed that there's a certain point at which adding more station capacity stops having any effect at all; this is also consistent with what you've described.  In general, I think the principle makes a lot of sense, and I know that something corresponding to it happens in real cities when large new projects are built.  But continued experimentation with this since my original post leads me to question the most crucial aspect of the implementation, namely, what the exact capacity requirements are.  As I mentioned in my first post, I typically use cogeo's combination bus and subway RTMT stations with doubled capacity, which comes out to 28,000 per station.  Typically, I space my stations the way you do, as you described in your answer to me in my thread about station spacing.  Yet stations with this capacity and at that spacing have nowhere near the capacity to allow full CAM construction.  Instead, I have to put stations of this capacity every two or three squares to get full CAM construction.  And when such construction is finished, most of the stations are barely used, as there are so many of them.  And most people use MT stations of much lower capacity.  So I think that the station capacity requirement, while good in principle, is set way too high; I'd recommend reducing it by at least half.

[xxdita]

There isn't exactly a station capacity requirement though, at least not one we can just change the settings of. My best hunch is the simulator is taking into account the congestion of any stations, along with the actual network capacities, and their congestion when considering the desirability for any specific zone.
For your purposes, I'd suggest taking a look at the Subjective Factor Threshold min/max properties in the Developer Files within CAM. Customizing them a bit may give you what you're looking for. Just make sure you get a backup of the files involved first.

[Shadow Assassin]

So it's CAM that's causing this behavior! 

Nope, not just the CAM, but the vanilla simulator too.

I've had this exact same phenomenon occur with a vanilla set-up... I knew it was something to do with desirability, but I never thought about just why it was happening. I always thought, "Hmm. If I plop a road-top mass transit station there... they'll come." but never about why it happened.

I use this little trick in developing all my cities. How else would I be able to get such large sprawly regions, otherwise?

[z]

For your purposes, I'd suggest taking a look at the Subjective Factor Threshold min/max properties in the Developer Files within CAM. Customizing them a bit may give you what you're looking for. Just make sure you get a backup of the files involved first.

No, this wasn't it.  These properties depend on traffic, and traffic was not a factor in what I was observing, as I described in my first message.  I looked through the rest of CAM and couldn't find any other likely candidates, either.  So I ended up coming to the same conclusion as Shadow Assassin - it's in the vanilla simulator somewhere.  If anyone knows where, or even some good possibilities, I'd be very interested in hearing about them.  Right now, this "feature" is stunting CAM growth unnecessarily in many cases.  So the CAM team might want to take an interest in this directly.

[xxdita]

Personally, having large tiles with over 8million population, I see no growth stunted by CAM, so I'm not sure what it is you think we should fix?
As for anthing related to traffic effecting CAM's growth, it would be the capacity for the streets within the zones, which can easily be upgraded to roads as needed, or if you're feeling amorous with the traffic sim, you can adjust the street capacit within that.

[z]

It's definitely not related to traffic.  To elaborate on my example above, in the core of my Downtown Chicago city, I have roads placed in an approximately 6x6 grid.  The capacity of these roads is 12,000 each.  Demand was high and has remand high (24,000 or close to it for all commercial types).  There was literally no traffic at all; commercial buildings across the river were soaking up all the residential demand.  But nevertheless, in the downtown core I got a very nice collection of skyscrapers, including Velacosma, growing long before I discovered this trick.  In fact, I'd been using CAM quite happily for almost a year before I realized that any limitation existed.  The limitation certainly isn't crushing, and as my case showed, it's easy to miss if you don't know it's there.  Yet as soon as I started plopping high-capacity MT stations in my downtown core, typically where the smaller buildings were, I got immediate growth, as I described above.

It's hard to say what's happening with your city of 8 million; there are so many variables in this game!  But if you're willing, I think it would be very useful to try an experiment.  Find a high-density section of your city where the buildings aren't quite as big as the others, or quite as high-capacity, or quite at the top of the growth stage range.  Stop the game and plop a bunch of high capacity MT stations (specifically bus and subway) in that area.  It would be good if the total capacity of the stations you plop is around 100,000, but a total capacity of 50,000 is probably enough to do the trick.  If it doesn't, just add a few more.  Make sure the stations are all within about ten squares of each other.  You can put them right next to each other; it doesn't matter.  Restart the game, and I would bet that you will see immediate new growth.

If you don't get new growth (which I would find very surprising), then that would simply mean that there are other factors at work here, and isolating them may be rather difficult.  But in any case, I would be very interested to see what happens if you perform this experiment.

[xxdita]

Sorry, but I think you keep digging for answers that have already been provided.

[Shadow Assassin]

The exact same thing happens with mayor mode trees, too, if I remember correctly (development starts up again after this, etc).

[RippleJet]

I've finally taken myself time to read through all of this.
This wasn't my first priority after coming back from the vacation, to be honest...

I think what is experienced when plopping a MT station is something called transient aura effect.

Aura Effect (more commonly called Mayor Effect) as such is not a factor in desirability.
It's the other way around, aura is dependent on the following factors:

  - Park effect
  - Pollution
  - School Effect
  - Hospital Effect
  - Crime Effect
  - Trip Length
  - Traffic
  - Tax Rate Change
  - Land Value and Wealth

The aura (mayor effect) is as such only an indication of how good your city planning has been.

In addition to the general aura, there's something called transient aura though.
It adds to the general aura, but is also mapped back into desirability.
A transient aura of -127/127 maps into a desirability of -100/100 for all RCI types.

First of all, transient aura appears when you plop a building with Mayor Effect.
It also appears when one of the following happens (the last one is unused):

   - A fire breaks out (transient aura effect -20 over 128 m)
   - Flora grows or is plopped (transient aura effect +3 over 32 m)
   - A civic building is plopped (transient aura effect +25 over 128 m)
   - A network tile is dragged (transient aura effect 0 over 0 m)

I think Maxis in this respect erroneously has made MT stations function like civic buildings.
The radius of 128 m (8 tiles) also matches what z has explained.

Since transient aura is decaying with 25% per month, you will soon loose the benefit though.
However, I don't think there is a reverse, negative, transient aura effect when you bulldoze a civic building.

Thus, an ultimate testing to see if my suspicions are correct would be to replop an existing MT station in the same spot.
That would also prove whether it's the traffic capacity or not that is the factor.

[z]

What you say makes perfect sense, and corresponds exactly to my observations.  Coincidentally, yesterday I decided to convert a few roads in one of my cities to one-way, so I had to bulldoze the RTMT stations along them and replace them with one-way RTMT stations of equivalent capacity.  Sure enough, when I was finished, I got a little new growth (not much, but this area was already pretty fully developed).  What's interesting is that my overall mayor rating for this city has been 102 for a very long time.  But of course that's nowhere near the maximum, and it varies from place to place anyway.  So I think you've got it - good job, RippleJet!   

This does leave me with one question.  If I have a city like this with such a high mayor rating, where I have essentially perfect health, perfect education, etc., and I still need to bump up the aura to get full development, is it possible that some of the desirability growth thresholds are set too high?  I know they were increased in CAM to prevent rapid abandonment of a newly constructed building due to lack of desirability.  But I've generated scores of new CAM buildings by plopping MT stations where buildings simply weren't growing before, and none of the new buildings has ever been abandoned due to lack of desirability.  So maybe this one parameter needs to be tuned downward a bit for the various RCI types.  At least, that's what it would seem from my (obviously limited) experience.  I'd be interested in your thoughts on this.

[RippleJet]

This does leave me with one question.  If I have a city like this with such a high mayor rating, where I have essentially perfect health, perfect education, etc., and I still need to bump up the aura to get full development, is it possible that some of the desirability growth thresholds are set too high?  I know they were increased in CAM to prevent rapid abandonment of a newly constructed building due to lack of desirability.  But I've generated scores of new CAM buildings by plopping MT stations where buildings simply weren't growing before, and none of the new buildings has ever been abandoned due to lack of desirability.  So maybe this one parameter needs to be tuned downward a bit for the various RCI types.  At least, that's what it would seem from my (obviously limited) experience.  I'd be interested in your thoughts on this.

You need to keep desirability and mayor rating apart! They are not the same...
A high mayor rating doesn't automatically mean you've got a high desirability for all RCI types.

E.g. for commercial offices, one important desirability factor is customers (=traffic).
Traffic however at the same time reduces the mayor rating in the area.

Park effect, school effect and hospital effect are other factors that increase mayor rating,
but have no influence on CO desirability. Landmark effect increases CO desirability though.

Landmark effect is an important factor that is often forgotten.
Landmarks and plazas are especially beneficial if you want to increase CO desirability.
Note that parks are good for increasing the desirability for R§§§ and I-HT, but not for CO.

It isn't meant to be easy to get high enough a desirability for CO§§§ offices.
Otherwise there wouldn't really be a challenge in growing a metropolis.

Besides, having a high desirability threshold helps keeping CO§§§ buildings together.
Proximity of other CO§§§ buildings is one positive desirability factor for CO§§§.

Then, if you really want to get a certain area to develop into CO§§§ skyscrapers,
you can always increase the transient aura effect in that area.

The normal way of doing this is to plant the area full of trees.
Each tree gives a small transient aura, and at the same time they reduce air pollution.

And, as we have seen, plopping a civic building gives a good transient aura effect.
To replop MT stations in order to achieve this effect is a way of cheating though...

[z]

OK, I think you've convinced me.  Now I have a much better understanding of what's going on and why.  And as long as there's a reasonable, non-cheating way to get full development, then I don't see the need for changing any parameters.  And you're right, of course, there does need to be some real challenge to the game.  So your explanations have given me a much better understanding of how the game works, and also of what the CAM team has done.  Thanks!

[b22rian]

outstanding thread here !

and very well explained..

nice to have you back from vacation ripple..

Brian

[Denon333]

Hi!That could be the thing but I mostly say no.The thing is that the taxes has to be placed right.If not,even the greatest cities suffer.