Author Topic: Terrain Geology effects  (Read 48662 times)

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monkschain

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Terrain Geology effects
« Reply #20 on: May 24, 2006, 12:38:30 PM »
Hi nikita, one way is to blend two terrain layers. The first is the straight terrain, the second is a glacier 'dome' created from a mask of the valley floors. The problem is, this is quite a tedious way to do them (en masse), and doesn't really entail any application-intelligence regarding these terrain types: it's superficial and not generalised: different mask for each glacier.
 What I'm describing is not necessarily a way to extract ice information from existing terrain: ie, this sediment in this high valley is ice, but rather a complete distinction within the app of ice volume vs terrain volume. I don't know if I'm right here, but isn't the sedimentation produced at the moment really soil/earth? A glacier bears little resemblance to soil in terms of properties. Would it be possible to modify existing deposition procedures to imitate a glacier flow or ice plugs? What would be the options for a generalised macro?

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nikita

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« Reply #21 on: May 24, 2006, 12:48:08 PM »
That sounds more and more challenging... I'll try to build a small macro and try some stuff...
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monkschain

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« Reply #22 on: May 24, 2006, 12:50:42 PM »
I'd better add that the method I described with the masks didn't involve World Machine  (necessarily) :wink:

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JavaJones

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« Reply #23 on: May 24, 2006, 05:57:59 PM »
Well, has anyone done any work on simulating this stuff as far as an "erosion" sim (like the normal erosion sims implemented in many of these terrain apps)? If yes, then it's probably something that could be implemented as a plugin, provided it doesn't require keeping track of multiple terrain "layers" and whatnot. Even then it might be doable. But it would really be easiest if it was just another way to modify a normal single heightfield procedurally using some certain rules. That may not go as far as you want it to, but it'd be a cool start. And hey, no one has done a glacier erosion simulator yet, so it'd be a first if WM had it. :D

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Sethren

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« Reply #24 on: May 24, 2006, 08:00:55 PM »
It would be nice if somehow World Machine could do erosion like Dymtry's MojoWorld Plugin has done but that is asking alot there......

Sometime ago i mentioned that i had lost the PDF but Stephen and Oshyan should have copies i beleave... they were and still are some very radical ideas i had at the time but i was wanting primarily a basis for larger scale non-homogeus terrains spanning a almost continent 1000 Kilometer + size using what are classifed as the 4 basic land types... Highlands, Coastal Plains, Continental Shield and Continental Plain... i wanted to generate macros for the types and mixing them on a very large resolution output map for the Pro version... the big problem however is creating the river networks from northern glacier melting and mountain chains draining into lakes and deltas..........   :shock:

The glacial erosion would result in the formation of the "Continental Plains" revealing the oldest rocks and lots of flat scraped terrains with long river flows... so up far north we would have ice carving the mountains out and down south older carved water/ice flow terrain like the plain states... certainly a nice idea for one hell of a plugin.............   :)

JavaJones

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« Reply #25 on: May 25, 2006, 12:10:27 AM »
Sethren, Dmytry's erosion is apparently procedural *at render time*, so it's not really something that is applicable to WM's heightfield domain. But it's very cool regardless. :D Have you noticed there have been no updates there for about 2 months though? I wonder what that's about...

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Sethren

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« Reply #26 on: May 25, 2006, 01:03:07 AM »
Really... i could have sworn i was looking at hieghtfield representation in MojoWorld before render time at his site???   I know there is something rather unique about his erosion that no one else can do yet... i just can not place what it is??? something about old and new erosion mixed over the same terrain fractal???

Who knows... i am sure he has something cool up his sleve... wish i could say the same for Planetside! something small from Matt or Jo would be better then nothing at all......

monkschain

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« Reply #27 on: May 25, 2006, 07:26:48 AM »
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Even then it might be doable. But it would really be easiest if it was just another way to modify a normal single heightfield procedurally using some certain rules.


How about a simple system where the app knows the difference between ice and rock and can operate on them both differently as needed (using modifications of existing devices). The difference would be represented visually on the model.
 A system is implemented that procedurally accumulates ice. WM would need to have either ice maps (at input), or better still, understand terrain altitude from which to procedurally generate those ice maps, or whatever.

If you keep things simple to begin with: a dialog to indicate the climate, latitude for that area. This combined with the altitude, waterflow (and possibly aspect) would determine the rates of ice formation.

If I'm understanding correctly how World Machine's erosion works: at the moment it's  a matter of take material from A and deposit it at B. Does it do this?

Supposing it does, A is currently defined by land.
In the case of ice, A is derived from water availability which determines the extents/rates of ice deposition. Water availability could be determined in part by the dialog mentioned above.

 Erosion and ice formation are coupled over time- ie they are not connected in series, but would a simple: do erosion, then calculate ice, work?

 If you get:
* internal descrimination between ice and land
* simple climate input (climate device?) to influence water availability
* procedural deposition of ice,
* Once you have static ice, you are surely then in a position to attempt moving ice, which is really just very large accumulations under specific topographies right? (glaciers are just moving water in a different form- WM already does erosion via moving water).

monks

monkschain

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« Reply #28 on: May 25, 2006, 07:40:28 AM »
Sethren said:
Quote
Sometime ago i mentioned that i had lost the PDF but Stephen and Oshyan should have copies i beleave...


Oshyan, do you have the pdf...anywhere?


Quote
they were and still are some very radical ideas i had at the time but i was wanting primarily a basis for larger scale non-homogeus terrains spanning a almost continent 1000 Kilometer + size using what are classifed as the 4 basic land types... Highlands, Coastal Plains, Continental Shield and Continental Plain... i wanted to generate macros for the types and mixing them on a very large resolution output map for the Pro version... the big problem however is creating the river networks from northern glacier melting and mountain chains draining into lakes and deltas.


 I read your post last year on very large terrains and had wondered how you'd gone on with that. This is uncanny, because these are exactly the same problems that issues that we are tackling over a ME-DEM. They've been lurking on the horizon for a bit. :) We're talking about rivers at the moment. Imo, rivers are THE most important consideration for this scale of work because at this scale you get to see the whole of the hydrology cycle, not simply a part of it. Mountains to sea to mountains.
 Have you had any ideas on how you would do this?- does the upcoming Pro version have any new solutions?

monks

Sethren

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« Reply #29 on: May 25, 2006, 01:16:26 PM »
Well as far as the very large terrains are concerned... we really have two options here... 1 Wait for World Machine Pro or 2 Wait for Terragen 2.

I did not go anywhere with the large terrain ideas... i am hoping the pro version has the solutions because of the large tile outputs, drawing tools etc...

Here is a basic drawing of an idea i had with a possible construction of Glacier Macro... it's a rough idea so forgive the sloppy aspect of it......  

http://www.ashundar.com/datas/users/1941-glacier%20idea.jpg

nikita

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« Reply #30 on: May 25, 2006, 02:39:02 PM »
Quote
Mountains to sea to mountains.

Still, all you need is the "Mountains to sea" part  :wink:

'will try this glacier macro tomorrow/later today (depending on the time zone you live in :P )

And pro will allow very large terrains as Stephen mentioned in the blog  :D
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JavaJones

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« Reply #31 on: May 25, 2006, 10:47:30 PM »
Sethren, what's unique about Dmytry's erosion is that he's able to do it procedurally *at all*. That it has theoretically "infinite" detail, just like normal procedurals. It's not really the specific look or result of his erosion that is special - it's not like he's simulating some new *type* of erosion. It's just special because he can apply it procedurally.

Erosion is usually an iterative process performed on a per-heightpixel basis and thus is inherently a finite resolution process. The simple way to get "infinite detail" erosion would be to sample a procedural terrain 1 height element per screen pixel (or more, ideally, for AA) and do erosion on that, though it would require some very complex manipulations for even that to work, and even if it did it would be very slow because each frame would require a recompute of the erosion for the entire visible terrain. What Dmytry has done is figured out some way to actually apply an erosive-type filter to a terrain and keep it procedural - or at least that's what he claims and what the results he shows indicate. Read up on traditional erosion models and then on what Dmytry is doing (he's written about it some before), you'll see the difference.

Monks, I'm fairly certain I do have that pdf somewhere but I've been through 2 computers since. :D I'll be able to dig it up at some point, but not immediately. Feel free to keep bugging me about it.

As far as doing ice/glacial erosion, basically you need to do the following:

1: Determine what effects ice actually has on a terrain and how it moves over and/or accumulates on the terrain. This sets the tone for everything to follow.

2: Determine what factors are involved in those effects. What is the effect of ice on different terrains, rock, soil types? How does slope affect it? etc.

3: Presuming (hopefully) 1 or at most a few major definable effects and a few "factors", you create 1 or more mathematical models that simulate those effects using simple per-pixel heightfield modification functions - add, subract, multiply, or more complex, but still operating directly on the heightfield based on some fairly simple rules. This is essentially how most erosion models work. You start with "rain" which defines a property of a certain amount of sediment carry, etc. which expressed mathematically is just a certain chance of picking up x amount of material and then y chance of depositing x amount of material at each point of traversal, at which point that "drop" stops. That's a very gross simplification and Stephen may take issue with it. :D But the point is that it really just comes down to simple operations on the heightfield based on a mathematical interpretation of what water does in the real world.

4: You create a device based on these simple mathematicla models of the effects of ice and the factors involved in its effects. Examples of this in the current device are the "rock hardness" values - take the real-world idea of rock hardness, which probably takes into account slope variations, etc. and then translate that into a mathematical effect on the system. In a glacier/ice model slope would probably figure heavily into it. You might have a "slope sensitivity" or "effect of slope/gravity" control. Figuring out what other controls you'd have and how they would translate to mathematics is the trick.

5: Once you have all this it should be a fairly simple process to create an input that determines where ice initially starts. An "ice mask" which would be defined just like any other mask in WM right now. No need to really have some new device type or anything, the "ice" would be unique to the "ice erosion" device though. So you couldn't model ice globally throughout the device chain, just in the one device. But it would have output for "final ice deposition" or whatever too, so you could then take that in to your 3D app and texture it properly, etc.

Now this *is* more complex because ideally you want to define a difference between ice and soil, where ice will also have volume. SO it's *separate* volume. Whereas a regular erosion model just moves the same "stuff" around - it's all soil. So depositing a chunk of soil here just makes things higher, the model doesn't keep track of what *new* soil is there, except to record how much soil was put there with the masks. But resulting heightfield incorporates that deposited material.

I suppose it might be possible to output the ice normally as part of the heightfield, but then to optionally just take the ice mask output and subtract that from the terrain, resulting in the soil height itself. Then you use the ice mask output as your "ice volume", maybe a separate heightfield in 3D apps that allow that.

I dunno I'm just blabbering here really, but this is the immediate, practical way I see of doing it, that fits within the current WM paradigm. Actually having some different data type for ice, if that's what you were suggesting, seems more out of left field.

Sethren, TG2 probably won't meet your needs for specific large-scale terrain creation. It will certainly have a heightfield editor in it and good procedurals, but unless you feel Vue and/or Mojo currently offer you what you need (as both have the separate elements that TG2 will better combine - heightfields and procedurals), then you probably won't be that much better served by TG2. WM will still be a better terrain modeler in general I think, for heightfields at least, especially with Pro.

- Oshyan

Sethren

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« Reply #32 on: May 25, 2006, 11:29:00 PM »
Ah-ha... OK!     I suppose it was those procedural details that tricked my eyes into thinking that the erosion was a specific specialized type besides just being procedural......  :D

Has anyone mixed both new and old erosion in the same terrain which is what is seen with mountains and the like... fresh water flows with older flows with larger scale deeper carvings in the mountains?  

I am thinking could not a erosion device with strong erosion settings and another erosion device with weak settings (new flows) be connected to a combiner device with masked ridge channels for the combiner device therefore both having old and new erosion mixed? Does this even make sense???

I am not going to pretend i know what i am talking about as far as the mathmatical/technical aspect of terrain heightfield generation goes... i just would like to try having a large mix of non-homogeus hieghtfield terrains split into four basic groups so i am hoping i can mix them with the Pro version because i want to put mountains where they belong as opposed to just scattering them anywhere and that is probably where the Sketch Shapes come into play because just simply generating the terrain types would break the geology rules!

I can use the Functional Blocks (Groups) that can be utilized for the Land Type Macro creation where the network can be easy to manage for converting the devices into a specific Macro... sense these will be Macros and not drawn the geology rules do not apply much here without the accurate placement of terrain using Sketch Shapes but perhaps with some work there can be abit of a workaround to get closer to the rules here???

and lastly for the very large-scale terrain and what i mean by large-scale is somewhere in the ball park of say 10,000 pixel output or so, just enough hieghtfield detail to clearly identify mountains and desent size hills... nothing to extreme perhaps... i can use the Land Type Macro Devices i want to do with the Tiled File Input Device to freely blend the larger terrains (Regional Land Types) into a more worldly-scale output so continents can be identified in the thousand+ or so Kilometers......

I know... wacky ideas i tend to think............       :roll:

nikita

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« Reply #33 on: May 26, 2006, 02:05:55 AM »
Quote
I am thinking could not a erosion device with strong erosion settings and another erosion device with weak settings (new flows) be connected to a combiner device with masked ridge channels for the combiner device therefore both having old and new erosion mixed? Does this even make sense???

Give it a try - have fun!  :mrgreen:
(that is 1 minute of work)
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Sethren

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« Reply #34 on: May 26, 2006, 01:25:57 PM »
Ummm... is it that easy to produce the effect? because i have not seen anyone do it or am i just crazy???      :)

monkschain

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« Reply #35 on: May 26, 2006, 01:30:25 PM »
Sethren- that seems to tell the story to me.

Quote
i want to put mountains where they belong as opposed to just scattering them anywhere and that is probably where the Sketch Shapes come into play because just simply generating the terrain types would break the geology rules!


Exactly. The Sketch Shapes tool should be very cool.

The new and old erosion sounds like something I should look into. A simple idea, but right in the area of what's doable.

I'll try and reply more fully as soon as I get a chance: Oshyan you missed one item from your list: Must get Stephen to implement it :) :)


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« Reply #36 on: May 26, 2006, 02:12:29 PM »
From what i understand the Erosion Device has the only option of going from light to very heavy erosion but not the two intermixed......

I just re-did my PC and keep on forgetting to install World Machine darnit... (Never mix Coffie and Benadryl) i should have a go at the erosion idea as well... i am very inexperienced at making good macros so may or may not work out......

monkschain

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« Reply #37 on: May 26, 2006, 02:55:52 PM »
Sethren, here is a nice breakdown of river styles:

http://www.geog.soton.ac.uk/users/WheatonJ/Definitions/QD0107.htm

monks

JavaJones

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« Reply #38 on: May 26, 2006, 03:44:29 PM »
Wouldn't the newer erosion just happen *on top of* the older, and thus simply chaining erosion devices would simulate it? That's basically what I recommended above in my first mountain suggestions post.

As for converting ice effects into mathematic operations on a heightfield, sure that could be hard, but a good start at least would be cataloging what effects ice actually has and what factors are involved in that. Start with step 1 and 2, that's something any one of us could probably do with a bit of research. Once that's done any reasonably clever programmer could probably figure out some mathematical approximations.

- Oshyan

Sethren

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« Reply #39 on: May 26, 2006, 10:13:45 PM »
JavaJones:

"Wouldn't the newer erosion just happen *on top of* the older, and thus simply chaining erosion devices would simulate it?"

Good question... i could give that a try and see if it is possible......