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Terrain Themes need critical review


Ssnake
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The next version of SB Pro will take into account the bumpiness value of the respective terrain on which you're traveling to model those ground variations that are too small for the terrain mesh that we're using.

Unfortunately, almost all the ground types in almost all the terrain themes have the "bumpiness" slider all the way to the right at 100%. This is bad, because this is supposed to represent the most coarse type of boulder-strewn rubble field one can think of. So, all you map and scenario designers, please have a critical review of the terrain themes that you are using. To give you a comparison chart, here's a list of typical ground types and the coarseness that I would consider "reasonable". You're free to use other values, but please be aware of the consequences. High bumpiness will slow down the top speed of vehicles - especially wheeled ones - and may actually affect the quality of gunnery on the move at high speeds.

  • Agricultural area: Up to 10%
  • Natural meadow: Up to 30%
  • Heath, scrub: Up to 40%, typically less though
  • Stony desert, detritus, bare rock, boulder fields: Up to 100%, typically maybe rather 75%
  • Swamp, moor: up to 20%
  • Forest ground: Up to 80%, typically rather 50% - in highly cultivated forests it may even be down to 20% (exception!)
  • Pure sand: up to 25%, usually just 15%.
    However: Pure sand is a rare find in nature. Some parts of the Sahara maybe (those that are usually shown in National Geographic program). More common however is
  • Sand/clay mix: Up to 70%, typically rather 30-60%
  • Gravel surfaces: Up to 55%, typically rather 40% or less

You may also want to consider the hardness values, with rock and concrete at 100%, water at 2%, Swamp maybe up to 20%, and everything else in between. The water content of a soil often is an indicator of its hardness.

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I can't say when, exactly, the next version will be released. "Summer '08" still is our best estimate. So, there is still time (I'm bringing this up early so you have time to have a look at the files).

It will affect every scenario ever made. They're all relying on existing terrain themes; these could be the default themes, but there are many custom themes out there as well. We want to catch as many of them as possible.

So every scenario developer should have a look at his own scenarios and check to which terrain theme it is linked, then open that theme in the map editor and fix it where necessary. Send me the theme file so we can include it in the next version, and update the scenario on the downloads page if it has been published there.

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The next version of SB Pro will take into account the bumpiness value of the respective terrain on which you're traveling to model those ground variations that are too small for the terrain mesh that we're using.

Unfortunately, almost all the ground types in almost all the terrain themes have the "bumpiness" slider all the way to the right at 100%. This is bad, because this is supposed to represent the most coarse type of boulder-strewn rubble field one can think of. So, all you map and scenario designers, please have a critical review of the terrain themes that you are using. To give you a comparison chart, here's a list of typical ground types and the coarseness that I would consider "reasonable". You're free to use other values, but please be aware of the consequences. High bumpiness will slow down the top speed of vehicles - especially wheeled ones - and may actually affect the quality of gunnery on the move at high speeds.

Is the effect of bumpiness also going to be VISUALLY displayed ;)(vehicle shaking a bit etc.)?

Since almost every theme has its bumpiness value set to 100% I guess this will cause serious problems if not changes by the designer - at 100% I'd consider it unplayable. So - why not just release new & corrected theme files in the next release instead (that would simply overwrite the current ones)?

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Is the effect of bumpiness also going to be VISUALLY displayed ;)(vehicle shaking a bit etc.)?

Yes, as far as vehicle motion is concerned. "Not yet", if we're talking about it being directly visible in the terrain or animated roadwheels. I could imagine that we'd be using a low resolution displacement map at some point so that if you reconnoiter the terrain in 3D mode you'll get an immediate impression of what to expect.

Since almost every theme has its bumpiness value set to 100% I guess this will cause serious problems if not changes by the designer - at 100% I'd consider it unplayable.

It's not that bad. you can still drive across such terrain with a Hummer which is one of the vehicles to be affected most. It's just that eventual time/space calculations for some scenarios may get out of whack because a timed counterattack arrive come too late then.

So - why not just release new & corrected theme files in the next release instead (that would simply overwrite the current ones)?

That's precisely what I have in mind. It's just that I didn't make most of the themes, so I would prefer if the creators of these themes took care of it. I will then collect the fixed themes so we can include them in the next release.

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Well, a 100% traction can probably be expected from dry concrete or asphalt. Dry clay soil would probably offer .7 to .8 traction while bare rock is probably down to .7 - not because it is inherently more slippery than concrete but because of the small bumps and dry sand which serves as a slip medium.

Dry sand I would consider to be in the .4 to .7 region (depending how pure and how dry it is). Slightly wet sand could have a hardness of up to .8 and a high traction of up to .85, but the more water is in it the softer and more slippery it will get (as any day at the beach will easily demostrate).

Ice should have a traction of around .1, snow could be from .1 to .25.

Wet grassland can be quite slippery, so the traction is probably around .3

For swamps I would consider a medium traction of maybe .5 or .6 but also a high drag of around .25 to .4 (the more compact the mud the higher both drag and traction, with the difference becoming smaller all the time). Swamp would have a more watery nature if it was raining and a more mud-like consistence while it is dry.

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The response so far has been less than enthusiastic. Maybe it's because people are waiting for a more detailed reference, so here it is for a "Woodland default" theme of a rather cultivated terrain, I should add.

Nr..Terr..Name.......Drag...........Traction.....Hardness......Bumpi.-...Dusti-

....................dry...wet......dry....wet....dry....wet....ness.....ness

.0...Dirt..........0,20...0,4......0,90...0,70...0,85...0,70...0,20......0,85

.1...Grass.........0,22...0,35.....0,80...0,60...0,80...0,72...0,30......0,40

.2...Sand..........0,30...0,18.....0,65...0,70...0,75...0,78...0,30......1,0

.3...Water.........0,51...0,51.....0,70...0,70...0,70...0,70...0,10......0,00

.4...Gravel........0,40...0,39.....0,60...0,58...0,70...0,70...0,40......0,51

.5...Bog...........0,40...0,51.....0,60...0,53...0,35...0,20...0,10......0,00

.6...Field 3.......0,20...0,40.....0,85...0,70...0,82...0,65...0,05......0,60

.7...Field 2.......0,19...0,41.....0,86...0,69...0,83...0,63...0,04......0,57

.8...Field 1.......0,22...0,39.....0,80...0,72...0,78...0,60...0,08......0,45

.9...Scrub.........0,28...0,35.....0,75...0,65...0,82...0,74...0,35......0,70

10...Field 4.......0,17...0,37.....0,82...0,77...0,84...0,68...0,10......0,70

11...Rock..........0,10...0,10.....0,90...0,88...1,00...1,00...0,80......0,60

12...Heath.........0,17...0,33.....0,78...0,63...0,72...0,67...0,40......0,70

13...Grass 2.......0,21...0,45.....0,70...0,58...0,60...0,35...0,15......0,10

14...Con. Forest...0,28...0,39.....0,80...0,75...0,82...0,75...0,60......0,05

15...Dec. Forest...0,30...0,42.....0,77...0,72...0,81...0,71...0,51......0,02

Stupid auto-formatting. Can't get rid of those spaces.

Anyway. These figures are reference, not command.

The meaning of the individual parameters must be seen in their context with other parameters:

  • Drag determines the maximum speed of any vehicle moving off-road.
  • Traction influences the ability to accelerate and may result in curve drift
  • The difference between drag and traction sets the limit for the slope angle that a vehicle can still negotiate. The smaller the difference, the more flat a slope must be in order to remain traversable
  • Hardness is without function at the moment but is supposed to influence the visualization in the future - how deep a vehicle will sink into the ground. Eventually we will also set a threshold for each vehicle at which point it will simply bog down, even if all other parameters would still allow travel.
    Finally, hardness may one day influence the speed with which infantry can dig themselves in.
  • Bumpiness will primarily affect the coincidence behavior of weapon systems (and eventually their accuracy while shooting on the move. It may also limit the maximum speed.
    In addition it will determine the protection level for stationary infantry against direct fire. It's supposed to represent an abstract value for micro structures on the ground that allow soldiers to hide. After all we are relying on a terrain resolution that is much larger than an individual soldier. So, infantry will not only sink into the ground in forests in the future but anywhere, and will therefore present a smaller target and profit from concealment while remaining in place.
  • Dustiness is self-explanatory. Keep in mind however that it references the amount of dust that will develop under dry conditions. This means that grassland usually will create dust clouds as well. Dry ground without any noticeable dust development will usually be rather rare. Salt flats come to mind, otherwise inherently wet grounds like bog.

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Here is the "Desert default" theme:

Nr..Terr..Name.......Drag...........Traction.....Hardness......Bumpi.-...Dusti-

....................dry...wet......dry....wet....dry....wet....ness......ness

.0...Broken........0,20...0,4......0,90...0,70...0,90...0,70...0,40......1,00

.1...Grass.1.......0,24...0,37.....0,78...0,62...0,83...0,73...0,35......0,75

.2...Soft sand.....0,39...0,25.....0,72...0,79...0,71...0,77...0,40......1,0

.3...Wadi..........0,35...0,32.....0,85...0,72...0,88...0,80...0,80......0,30

.4...Gravel........0,37...0,35.....0,62...0,60...0,75...0,75...0,40......0,60

.5...Dry lake bog..0,45...0,49.....0,51...0,47...0,25...0,21...0,05......0,00

.6...Rippled sand..0,35...0,31.....0,75...0,80...0,75...0,69...0,49......0,95

.7...Patchy flat...0,27...0,25.....0,87...0,65...0,83...0,73...0,17......0,91

.8...Rough.........0,28...0,32.....0,77...0,67...0,84...0,80...0,38......0,77

.9...Scrub.........0,30...0,37.....0,82...0,74...0,84...0,76...0,37......0,77

10...Dry lake......0,06...0,45.....0,92...0,75...0,97...0,62...0,02......0,20

11...Rock..........0,10...0,10.....0,90...0,88...1,00...1,00...0,80......0,60

12...Hard sand.....0,17...0,25.....0,78...0,79...0,87...0,73...0,15......0,77

13...Grass 2.......0,21...0,32.....0,75...0,71...0,77...0,72...0,22......0,80

14...Date palms....0,25...0,30.....0,75...0,68...0,77...0,70...0,60......0,51

15...Coco palms....0,22...0,27.....0,72...0,69...0,71...0,73...0,55......0,45

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what kind of real value does bumpiness accord with?

the unstabilized up/down movement of the sight? if so, whats the max/minimum(in mils)?

or is it the ditch size of the ground?

again if so, what is the max/minimum values(in cm)?

as for the bare rock, in norway, theres no sand on bare rock, and it basically has the same grip as dry asphalt.

however, we also have loose rock terrain, where you have huge carpets of medium to large rocks that has been displaced by glacial ice, which basically would have a high slippery value as well as a high bumpiness value, because as you move over them, the rocks will move and roll around. driving over such terrain with a humvee is most likely to see you topple over if driving at any speed higher than a slow crawl, plus theres a high likelyhood of simply getting stuck on top of a rock outcrop.

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The intent of this thread is to create awareness among the mission and map designers to adjust their terrain themes NOW, and to submit them to us, so that we can incorporate these adjustments WITH the next release so that there is no need to fix things afterwards.

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what kind of real value does bumpiness accord with?

the unstabilized up/down movement of the sight? if so, whats the max/minimum(in mils)?

or is it the ditch size of the ground?

again if so, what is the max/minimum values(in cm)?

It's a decidedly unscientific fudge factor that is indicating roughness at below mesh width scale. A detritus area with large boulders would represent "100% bumpiness". The salt flats of Bonneville, UT would probably mark the lowest possible natural bumpiness of 2%.

There is a huge variability among grounds. Sand can be flat, rippled, or mount to giant dunes. Consequently the bumpiness will vary although I would never set it any higher than 40%, with the "average" sand surface probably being around 20%.

I think I gave a few examples in the first post of this thread. They should be used in conjunction with the tabular overview that is at the end of page 1 of this thread.

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It's a decidedly unscientific fudge factor that is indicating roughness at below mesh width scale.

what does that mean, the frequency of up/down movement, the amount of up/down movement? both? and by how much? (bumps per second, bump-size in mils)

any numbers on how much its going to slow down a humvee/M113, when set at 2%-40%?

or how much the vehicle is going to shake in degrees and frequency when set at 2-40%?

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any numbers on how much its going to slow down a humvee/M113, when set at 2%-40%?

Here's the result of a speed test - assault route, cross country, flat, straight for 3790m. Bumpiness ranged from 0% to 100% as indicated:

Start: 00:42 3790m M1025 HMMWV

.0%....10%....20%....30%....40%....50%....60%....70%....80%....90%...100%

Finish (mission time)

6:11...6:39...7:01...7:19...7:37...7:59...8:15...8:29...8:43...9:00...9:13

Time (absol.)

329s...357s...379s...397s...415s...437s...453s...467s...481s...498s...511s

Time (relat.)

100%...109%...115%...121%...126%...133%...138%...142%...146%...151%...155%

Velocity in m/s:

11,5...10,6...10,0...9,55...9,13...8,67...8,37...8,12...7,88...7,61...7,42

Start: 00:26 3790m M113A3

.0%....10%....20%....30%....40%....50%....60%....70%....80%....90%...100%

Finish (mission time)

6:05...6:08...6:13...6:17...6:21...6:24...6:26...6:31...6:35...6:39...6:43

Time (absol.)

339s...342s...347s...351s...355s...358s...360s...365s...369s...373s...377s

Time (relat.)

100%...101%...102%...104%...105%...106%...106%...108%...109%...110%...111%

Velocity in m/s:

11,2............................... ... .............................10,05

I should probably mention that this is an intermediary setting where the effect of bumpiness is not yet full in force. It's just in indicator about the direction that we're taking, not the final result.

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OK, so you are saying that the next version will break all the existing scenarios?

Isn't a fix possible with the next version that will edit (replace) the existing canned terrain themes with files containing the correct settings?

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OK, so you are saying that the next version will break all the existing scenarios?

That's an exaggeration. Vehicle mobility will be impeded but not prohibited by 100% bumpiness. Still, you are right insofar as for MOST terrain types in MOST scenarios and terrain themes the bumpiness defaults to 100% which isn't reflecting reality well. This worked in the past because SB versions until about 2.380 simply ignored the bumpiness value.

Now, of course we could do the radical and simple approach and simply apply a standard theme to all the scenarios and be done with it. That will eliminate all the other settings that a theme/map/scenario designer may have had in mind, starting with drag and traction values and then all the way to the selection of textures and plants.

The best solution overall appears to me if each mission designer would review the themes that he used for his scenarios, and adjust them according to the guidelines that I posted earlier in this thread, then submitted the corrected files to eSim so that we can include them in the next release.

If we don't receive them in time, we're left with two alternatives - "fix" all scenarios by applying one out of three or four standard themes, or leave everything unchanged and leave it to the community to clean up the mess after release.

Neither alternative is particularly appealing to me. But ultimately the decision is in the hands of the community.

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In the mission editor, click on Map... Info. That will give you a list of the files - height map, terrain map, and theme.

Even scenarios with the default theme will need to get updated unless we change the scenario file structure. We could add a routine that attempts to update the theme file whenever a scenario is being loaded, but that's a new source of trouble since some theme files will be updated, others outdated, some absent. So the "automatic fix" will only fix SOME scenario files and leave others effectively unchanged.

It's better to leave this duty to the actual mission designers since they know their original intentions best.

Having said that, I'll upload the new default themes for woodland and desert in a few minutes.

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