Visportalling City Sections

[Springheel]

Can anyone recommend a good map to use as an example of how to visportal open city areas? I'm having a difficult time with my map. At the moment Return to the City is the only one I can think of with a fairly open city area, but I know it had visportal problems as well. Perhaps there is a test map that would be useful?

[Serpentine]

I got quite far in optimizing one of the beta versions of RtTC, if its around I will upload it.

 

Its quite hard to actually optimize after you have designed outside areas, its part of the reason I have started writing a TDM specific guide on the topic. That said, since the guide is not complete and it will be a translation of a really good guide for HL2 to TDM, I think you can actually learn quite a bit from the HL2 version for now.

http://rvanhoorn.ruhosting.nl/optimization.php?printable

 

Quite a few of the topics DONT apply to TDM, however for city areas there some that are quite close.

"Tip 1: Don't enclose your map in one huge box" - read that. Instead of putting the sky portal at the start of the wall, try place them in the middle of a roof, to divide the house into two halves.

"1) not seeing around the corner" The best way to deal with corners - can be applied to open areas but requires some hefty jiggling brushes around, but this should be how mappers deal with visportaling internal corners! (In HL2 visportal texture is called "Hint", might sound strange reading it)

"2) Not seeing over or under walls/buildings/other objects" worth reading, harder to apply but helps to think like that.

 

The later sections are helpful, but the HL2-centricness is a bit hard to translate.

Areas in TDM maps to check for examples :

Height separation : training map, between the climbing area and the canal area next to it. (can you also see how it could be divided easily with a skyportal through the roof? my later revision of the map changes to that.)

Portalling detail windows : training map, the tower next to the archery range's windows.

 

Cant really think of any others off hand - I dont dig around eeeevery map

 

Over all the concept will be to divide areas into rooms using skyportal or alternative materials - once the cell-like state is reached, open up the routes between them and visportal those up. Open windows and such be closed with portals to keep lighting and particle costs down. If you need to keep rooftop access... well thats a whole new world of pain.

Edited February 25, 2010 by Serpentine

[Springheel]

I started making my map before I even knew what visportals were, but I'm obviously not keen to go back and rearrange everything now. I'll look at those resources you mentioned, thanks.

[Springheel]

Another visportal question...is there an easy way to find leaks that might keep portals from closing? I'm finding a lot of my portals are open even though they shouldn't be visible. All it takes is a tiny crack somewhere, but isn't that like trying to track down a leak without a pointfile?

[demagogue]

In some cases you can create a leak to the void nearby the broken portal, with the player_box on the other side, and the pointfile will (or should) run through the crack in the portal. (Or you can save the whole thing as a prefab and copy it into an artificial room with the player_box and a leak to void to artificially create that situation.)

 

If neither of those options are convenient then it's just hard. One thing you can do is create an additional thin brush just to cover the portal's edge all the way and that works. Also keep in mind sometimes, when there is a small protruding sliver left in a brush, it won't render (the brush-blackout effect) and will kill the portal that way. So sometimes even though the entire portal edge is covered, it can still get killed, so you should take out any protruding slivers if you think that may be the case.

 

For the record, I thought the portal work I did for Patently Dangerous was pretty decent for open streets & rooftop access (not to brag, but just because I know it so intimately). It has streets that make a winding figure 8, with portals at each intersection (with some overlapping triangle portals to mesh with roofs), and the roofs of the inner-houses touch the skyportal to break up the leafs in the 8's negative space... and once the portals were all working the performance improved a lot (two are still broken iirc, though).

 

I think if you kept that same principle you could do a checker-board layout okay; with roof access along the leaf edges. You couldn't walk *over* the roof to the other side (unless you can afford to), though you can mitigate that a little by having lower awnings that go "over" along the edges.

[aidakeeley]

In some cases you can create a leak to the void nearby the broken portal...

 

Sorry to interrupt, but just for a second...

 

When you were young did you ever imagine that you'd unflinchingly start off a statement with something like that -- all the while with absolutely no hint of ironic or satirical intent?

 

[Fidcal]

For details of testing for internal leaks:

 

http://wiki.thedarkmod.com/index.php?title=Performance:_Essential_Must-Knows#Internal_Leaks

 

Jdude has a good internal wip city map on SVN where the performance is pretty good @ jdude\edridge.map

[Melan]

Can anyone recommend a good map to use as an example of how to visportal open city areas? I'm having a difficult time with my map. At the moment Return to the City is the only one I can think of with a fairly open city area, but I know it had visportal problems as well. Perhaps there is a test map that would be useful?

Return to the City is probably the example to use in the "how you shouldn't do it" section. What's more embarrasing is that people came up with a lot of good ideas on how to fix its problems, but I was then flooded with IRL tasks and couldn't do the actual work.

 

All I can think of as examples is Thief maps - e.g. Calendra's Cistern and Bad Debts (smaller self-contained areas separated by "corridors" or small rooftop connections) yes, Calendra's Legacy and Disorientation (continuous cityscapes mostly built in larger boxes) no. I have actually wanted to write a big tutorial on building city style maps for a while (most of which could be applicable to Dromed as well - both theory/philosophy and practice), but again, IRL. I promise I will do it when I can get things together.

[Goldchocobo]

A couple rules that will save you many, many hours of headaches:

 

1. The best thing you can do is map out your map on paper before you get to work.

2. Make sure to incorporate many winds and turns. Winds and turns = visportals that actually close off. Also, the less portals in view at one time, the better. Having too many portals open/close at once actually causes crashes and piss poor frame rates.

3. The smaller the portals, the better.

4. DO NOT "design, then portal later". OMG this has caused me literally about 40 hours of extra work on my map. Yes, 40 hours (its a massive city).

 

Good luck!

[STiFU]

4. DO NOT "design, then portal later". OMG this has caused me literally about 40 hours of extra work on my map. Yes, 40 hours (its a massive city).

That's definitely the most important part. Back in the days when I worked with T3ED, I started mapping just like Springheel not knowing what visportals actually are. After half a year of work I noticed that my map was incompatible with the engine... Man that sucked!

 

@Melan: The examples you posted might help inspiration, but should definitely not have any influence on your map-layout in any modern portal engine. Rule number two and four of Goldchocobo's golden rules would be broken!!

[Baal]

I redid the visportals of Silenciums "Thieves!" map. The early versions weren't visportalled optimally, too. It's not that big but I think it is a good example.

[demagogue]

Another thing... Maybe obvious but I didn't figure it out until later.

If you are using a checkerboard-paradigm for streets, where streets are "tunnels" (with skybox ceilings), buildings in the middle touch the skybox, and portals are at the intersections (making each block a leaf), I learned it's a good idea not to actually make it too much like a checkerboard pattern since that gives you long lines of sight down the aisles. It's better if you stagger the streets so there are more "T" or "H" junctions and less "+" junctions, like a jumbled checkerboard. It's probably better anyway because these are medieval streets and should be laid out a little haphazardly... You could even have maybe one or two main longish roads (that wind a bit) with streets branching off them.

 

This image isn't the best example because it's still too regular, but it gives the message "no long lines of sight":

http://www.scientificamerican.com/media/gallery/2B21EB44-BA10-8BF8-02EDC7FC3DF3CDEF_2.jpg

[Springheel]

DO NOT "design, then portal later".

 

Well, as I said, I've already broken that rule. I started this map about two years ago, after the St. Lucia release, and had virtually no idea what visportals were or how they worked. I didn't make the "surround it with a giant box" mistake, but probably every other one there is to make.

[STiFU]

You might have to add some more structures to make proper visportaling possible then, like e.g. tunnels and gateways. Maybe also reshuffle the map layout a bit if possible at all.

[Serpentine]

Spring, just as something that would be handy. While you are looking at this and when/if you make progress can you perhaps save a before and after copy and a few hints as to what you changed etc? I think this is something that would be very handy as the problem seems to be cropping up a lot lately and looking at how other people do things is always a great way to learn Dont worry if its too much effort!

[demagogue]

You might have to add some more structures to make proper visportaling possible then, like e.g. tunnels and gateways. Maybe also reshuffle the map layout a bit if possible at all.

 

This is a good idea. If you remember, there's a tunnel in the NW corner of Patently Dangerous. It was totally a post-hoc thing where it had been an open street before and I just covered the whole thing up and made it into a tunnel to shut it all up with portals and to drop the lines of sight. So that's one example of how to do something like that.

[Melan]

@Melan: The examples you posted might help inspiration, but should definitely not have any influence on your map-layout in any modern portal engine. Rule number two and four of Goldchocobo's golden rules would be broken!!

Actually, I am pretty damn certain the (positive) examples I cited would work in DarkRadiant; I have designed one and used the other as one of my main case studies to learn Dromed building methods (the other being Assassins, a TDP OM that would also make a functional TDM mission). The reason they would work as TDM missions is that both FMs are highly compartmental; individual scenes are often detailed by engine standards but they are always self-contained areas separated from others by relatively narrow tunnel or window type transition segments; moreover, both missions use convoluted architecture to neatly break up space. This fulfils Goldchocobo's points 2) and 3); I would argue that 1) and 4), while good practice, are procedural issues - what matters instead is the end result*.

 

There are engine differences - the main issue in Dromed is to keep polycount under the dreaded 1024 threshold, while DarkRadiant can push a lot more polys but you have to watch for open portals. This is the reason Return to the City is flawed from a design perspective - it was made with the old mindset, and while it hides long sight lines more or less well, portals remain open in ways that were unforeseen and unintended. In comparison, Patently Dangerous uses a lot of unassuming tricks to close portals, while Saint Lucia is a textbook case of compartmental building - although if I had to criticise it, I would say it does it all too transparently, and feels a bit "tunnelly" as a consequence.

 

_____________

* - Granted, Bad Debts at least was made according to a drawn schematic, although it turned out to be much more sprawling than first intended over the design process.

[Springheel]

For details of testing for internal leaks:

 

http://modetwo.net/d...#Internal_Leaks

 

That's a great resource, Fidcal, thanks.

[STiFU]

Actually, I am pretty damn certain the (positive) examples I cited would work in DarkRadiant;

Uh yeah, sorry. I just directly jumped at those classic thief map examples. Sometimes I tend to read a little inattentively.

[Baddcog]

I think the best way to draw up a layout is to think of it less of modern 'blocks' and streets that go around buildings and more like the shape of a tree.

 

The player can start at the trunk, then split off in 2 directions, then later they could split into other directions.

 

And try to almost never have all sides of a building reachable. Never have intersections too close together (so you can't see down multiple strets at once).

 

Rooftops are fine but try and make them more like ledges the player can go along, but have very few the player can go across. If you want a player to go over a roof, sandwich it between 2 tall buildings so the player is going through a large 'doorway' and they can't reach the top of the 2 buildings on either side (so the tops touch sky).

 

I actually think Saint Lucia (while not extremely large) is a great example of how to layout city streets, especially for the time period/setting.

 

Long windy corridors, some rooftop/high window access, but areas that don't lead to or look into other areas. Some tunnels put in to portal off. A great place for a new street in SL would be going off 90 degrees on the start side of tunnel, it could even wrap back around to the start point. And it would make an excellent and interesting layout. While a modern grid pattern is really not intersesting at all, and is very hard to optimize.

 

As far as released missions, I think Patently was almost too close to the modern grid layout and was probably right on the edge of being optimizable (I haven't looked into it too much) but the lack of too much up high rootop access was the saving grace. The buildings in the middle were tall and unexcessable.

On the other hand was Return which is probably alot closer to a 'better' street layout for optimizing, the main issue there though was too much roof access and just too many sightlines that can't be blocked.

But then again I've never released a city mission (everytime I get locked into trying to be too realistic/modern I guess and I'm not happy with how they end up).

But I think if you limit rooftops more (like patently, and twist the streets more like SL and Return) you get the perfect mixture of looks, gameplay and performance.

 

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I guess the training mission is a decent example too. At no time playing through it did I feel like I wasn't in a real place. Didn't have to access every building, climb on every roof top or see areas beyond the play area.

[Tels]

Most City missions also seem too "flat". Esp in areas against hills or in river valeys you can have quite steep streets and this can also help visportaling. If a street goes left and then up, you can better seal it if it would go just straight. SL was a bit flat at the start, but the hill was very good building a "different" shape.

[Melan]

Most City missions also seem too "flat". Esp in areas against hills or in river valeys you can have quite steep streets and this can also help visportaling. If a street goes left and then up, you can better seal it if it would go just straight. SL was a bit flat at the start, but the hill was very good building a "different" shape.

 

That's a bit hazardous from a design standpoint, though, since when you are going down along a steep street, you have to answer the question of "what do I see behind these buildings?" The higher the player can get on a vantage point, the harder it is to preserve the illusion of a logical* environment behind the immediate scenery. This is where polycount can explode, or you have to raise really high "walls" or facades which then poses other problems.

 

* Logical from the perspective of the game environment, not necessarily conventional reality.

[Springheel]

How useful are horizontal visportals in city streets? I haven't read much about them yet. If there is a courtyard with walls surrounding it, is it generally a good idea to cork it with a visportal?

 

Also, is it better to have visportals butt up against brushwork, rather than another visportal? If you make an "L" shape using visportals, then the entire thing will open if any part of it can be seen, correct?

[Baddcog]

Horizontal are good in some instances. I found 2 spots in Return that could be sealed quite well from the ground level (where player spends most time), but above that they'd do almost no good.

 

Could work alright in a courtyard, but would only close off stuff below it on other sides of the walls.

 

If you have to do an L shape do it, you can always remove if it doesn't seem to help. But generally the smaller and fewer you need is best.

When you start building shapes with them you start getting to the point where you are probably trying to close off too large of an area.

 

I think the tricky thing with them is when mappers look at where they are placing them they might think:

 

'this vis-portal is around the corner from that one, so the corner will block line of site, so they will close'

 

But that's not the case. Terrain brushes don't block views of vis-portals of each other. It's whether or not a straight line can be drawn through them from the players point of view (doesn't matter if the player can see the second one or not). You have to imagine x-ray vision.

This is why very lare ones don't work very good, because they are such a huge window it's hard to not draw a line through them from many points of view.

 

Putting them 90 degrees to each other works well (but spaced out), because if you are looking through one (say they are both 8' x 8') , then the second one won't be 8' wide, more more of a thin sliver from the side view. Harder to draw a line through the thin sliver than through an 8' gap.

----------

 

I agree with Tels though, hills can help and make it more interesting. But Melan has a point, it makes it harder to block views over lower buildings.

So these are areas that need alot of consideration.

1st: at top of hills don't let players up high. Although the low spots will be better for rootop access.

2nd: the low buildings can have facades behind them to make it look like tall buildings are back there. But, that makes it harder to allow players on those rooftops, or behind those buildings.

 

Unfortunately we have the option of skyboxes, but the leaning and head bob mess it up. Without leaning and head bob you can place a very smal scale model of a city in the backdrop for a realistic 3d skyline.

I uploaded a test map you guys can check out.

But we need the code fixed so the buildings don't bob and lean with players head.

 

Basically you build a skyline around your map, move it off to be centered around 0,0,0, and scale it down to a 16th. Then you seal around your playbable area with skybox.

The draw back is that all that renders all the time (but you can keep it fairly simple, and it looks great). The upside is you can have great 3d detail that makes your city look large and deep from any angle, and it takes very little space, can be completely clipped so no pathfinding is done (or you can have birds flying all over), and doesn't require any trickiery with portals, etc..

[Tels]

That's a bit hazardous from a design standpoint, though, since when you are going down along a steep street, you have to answer the question of "what do I see behind these buildings?" The higher the player can get on a vantage point, the harder it is to preserve the illusion of a logical* environment behind the immediate scenery. This is where polycount can explode, or you have to raise really high "walls" or facades which then poses other problems.

 

* Logical from the perspective of the game environment, not necessarily conventional reality.

 

Er, not I don't think you did understand me What I mean was, visportaling aside, people also build mostly flat streets, while a lot of the (esp. smaller) cities in the villages and near rivers, hills are quite steep.

 

However, you can add a sort of "tunnel" (a house build over the street), and if the street raises on either side, you cannot look along the street through the tunnel, from up you always only see the thing covering the tunnel.

 

Adding bends is the most easiers form, but 2D bends are also easily disovered by the player (a lot of games have a lot of L-shaped "tunnels" in for instance office environments), but a step-tunnel is something different and so it can enhance game immersion while still making visportals easier for you.