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Dan Ritchie
10-31-2016, 10:58 AM
Pretty simple trick, but you may not think about it being that easy.



https://vimeo.com/189660021


https://vimeo.com/189660021

prometheus
10-31-2016, 02:25 PM
yah...good trick to use two objects, some cons that it takes double the amount of polys to pull off something that should be in one object with half the amount of polys I think, depends on how much more of terrain objects you got and how many polys they consists of, itīs definitly a usable trick though.

The erosion type may be a bit limited though, more as thermal weathered blur erosion, and not that nice channeled flow erosion.
I would probably go with sending any terrain object made in lightwave to worldmachine as a height map and run erosion filters on that though, or copy a procedural displacement and make them alpha layers and control amount with some additional previous gradients, all in standard layering without nodes.

Thanks for sharing.

Michael

Dan Ritchie
10-31-2016, 02:35 PM
Yeah, it's not really erosion, it's sediment from erosion... 2 different things. I'd love to still discover a way to do erosion carving in lightwave natively. Howler will do it. it's like a particle gag that carves trenches into the landscape. World machine does it too.

Since there's 2 objects, you can use different subdivision levels. Since snow or sediment is smoother by nature, it doesn't need as dense a mesh.

prometheus
10-31-2016, 05:00 PM
Yeah, it's not really erosion, it's sediment from erosion... 2 different things. I'd love to still discover a way to do erosion carving in lightwave natively. Howler will do it. it's like a particle gag that carves trenches into the landscape. World machine does it too.

Since there's 2 objects, you can use different subdivision levels. Since snow or sediment is smoother by nature, it doesn't need as dense a mesh.


Yes I recall you did some mini showcase of howler and erosion for lightwave..though I think it can be defined a bit as a hack.

I suppose true good looking erosion requires proper flow algorithms and evaluate the geometry by geo or heightfields created, then return a new heightfield based on that, I wonder if particles or fluids inside of lighwave could do some calculation that could be used, maybe..but probably unnecessary to go through all that setup in order to retrieve an erosion map.
As I said, you could just render out a height map from the geometry and import to world machine and add erosion.

One thing that I havenīt seen is erosion on advanced cliffs or structures that would have a certain normal direction overhang, such thing isnīt possible with world machine, maybe substance designer/painter could do some hack.


Darn it..you got me inspired a bit to start working on such stuff, again.. itīs been a while since I fiddled with landscapes, deformations etc..I really donīt have time for it now, since I will start working on a job not related to 3d the next week.

Dan Ritchie
10-31-2016, 05:03 PM
.though I think it can be defined a bit as a hack.
I suppose true good looking erosion requires proper flow algorithms and evaluate the geometry by geo or heightfields created, then return a new heightfield based on that

What you describe is exactly what we do.

In howler, we emit particles that flow down the height map along the contours and apply splats to a texture, pretty much the way rain would, in a general sense, so I wouldn't call it a hack. We convert the height map to a contour/velocity vector field, and that controls the particles. The particles have a downward force like rain, and the vector field has a upward and outward force, like land. The only thing we don't handle is volume accumulation of water particles. We then subtract the splat map from the gemetry. Sidiment however is handled pretty much like what you see in the video.

prometheus
10-31-2016, 05:55 PM
What you describe is exactly what we do.

In howler, we emit particles that flow down the height map along the contours and apply splats to a texture, pretty much the way rain would, in a general sense, so I wouldn't call it a hack. We convert the height map to a contour/velocity vector field, and that controls the particles. The particles have a downward force like rain, and the vector field has a upward and outward force, like land. The only thing we don't handle is volume accumulation of water particles. We then subtract the splat map from the gemetry. Sidiment however is handled pretty much like what you see in the video.


Thanks for the clarification on that, Thatīs great...have you tried it on things like cliff type rocks?

Dan Ritchie
11-01-2016, 11:00 AM
We do height maps, so we don't do overhanging type stuff.

Typical result as an image map looks like this.

134949

prometheus
11-01-2016, 11:31 AM
We do height maps, so we don't do overhanging type stuff.

Typical result as an image map looks like this.

134949


Yes I know, and I figured such, I was throwing out the question more hypothetical as if you have experimented with a way to perform erosions taking place on cliff parts, cliff and sides of rocks which shape has a normal direction that simple heightmaps canīt influence.

Imagine some pillar of rocks with bulging boulder shapes, but you would still like to have some cool wind styled erosion..normally I guess one would need to actually sculpt in such erosion and limited to your own perceptions and skills on how to do that in combination with finding proper reference for it, or use displacement maps and tweak and tweak till something looks good, it will however not be anywere near a real wind erosion or some water erosion flowing around that pillar.

I do not have substance painter, but I think I need to seriously look in to that, I think the materials itself may take in consideration the curvature of the objects, or if you can get a good particle weathering effect going on.

Dan Ritchie
11-02-2016, 12:47 PM
I wonder if Acid from the Polk collection could be used with particles. I dont' have it to test.

prometheus
11-02-2016, 03:04 PM
I wonder if Acid from the Polk collection could be used with particles. I dont' have it to test.

I donīt have it either, you may want to try dpontīs particle paint, or look at using nodes to retrieve splat data, brian phillips had a tute on that up on his site, though I think he removed those from public showcase.

bobakabob
11-02-2016, 03:41 PM
Thanks Dan, there are some really nice landscape tutorials there. Great texturing and renders.

I discovered this landscape trick by accident a while back - you're right, it's so easy I almost deleted it for some irrational reason but it looks really convincing. It also works well substituting sand or fine rubble for snow.

bazsa73
11-02-2016, 05:09 PM
Nice tut Dan, I had another approach for snowy mountain but I try this too or I combine the two. Mine was based on gradient slope. Where the geometry was steep I left the terrain sharp and craggy but where it was flat I masked it with a smooth texture.

jwiede
11-04-2016, 02:20 AM
One thing that I havenīt seen is erosion on advanced cliffs or structures that would have a certain normal direction overhang, such thing isnīt possible with world machine

Are you aware of any terrain-modeling program with such capabilities? I've yet to run across one that supports such things.

prometheus
11-04-2016, 08:18 AM
Are you aware of any terrain-modeling program with such capabilities? I've yet to run across one that supports such things.

One thing I havenīt seen :)
No I am not aware of any terrain modeling program that could do that..thatīs why I thought the route of using substance painter would be the only option today, though it would involve more work.
Not sure if the new release of vue have something supporting that,w may have to ask a about that over at their forum.

gerry_g
11-04-2016, 10:49 AM
how would you imagine substance doing that, have I missed something, could make overhanging low polly geo in ZBrush then detail it and re apply it as a hight map using offset to normals rather than Y, then again I could model something in modeller and do the same

prometheus
11-04-2016, 11:18 AM
how would you imagine substance doing that, have I missed something, could make overhanging low polly geo in ZBrush then detail it and re apply it as a hight map using offset to normals rather than Y, then again I could model something in modeller and do the same

Thatīs human modeling design approach ..opposed to natural force design, such as particles driven by wind force or fluds, and then running around a 3d object, from where a 3d displacement map can be extracted, and since erosions ofthen carve, that should be some sort of inveted displacement.
Sure you could manually eyeballing sculpt it, nothing wrong with that, it may take longer time and more work and you would need a good sense for it including knowing something about how erosion flows and works as well, You could also simply apply displacement layers in layout.

As for substance designer, I just figured it has wethering particles from what I have seen to create the textures, though those examples may not be anywhere near a true erosion flow..and I havenīt seen any examples of such either, merely wethering with dust directional textures, scratch etc, it was just a thought.

I dunno, maybe doing it more complex than it has to be for the fun of it, meaning sculpting a cliff or rocks, then print them out at reasonable small size, and make them in such way you can cast in plaster or some clay, then erode them in real life :) then scan them in :) lol.

I actually have had a project in my mind, but for real life sculpt, where I make a large frame board with small dents, indents of clay or something else, and then let plaster poor down, plaster with various mixes of percentage of plaster, some being almost water, then let that pile up like some sort of natural process of stalagmites, just for getting intresting flowing wall sections and put in the walls at home.
I actually have had project sculpt, havenīt gotten anywere with it, it would take a bit of space to do maybe, I could try with much smaller scale and a simple small frame board and see how it goes.

prometheus
11-04-2016, 11:37 AM
I suppose you could fiddle around a lot with particles and set it to stick and a cliff as bounce or stick object and tweak it so it flows decently with some variations, then connect the rock surface to dp particle paint and get a procedural map to use as inverted displacement, then bake it if it is possible, bryphi also had a sample of extracting color data with nodes without particle paint.

This is also an example where you may want a true sculpting tool inside of layout, working in scene context where you sculpt in heights dentīs and indents, cavities, and then instantly run a particle simulation on it to see how the particle flows in cavity or around dents, rather than going back and forth in modeler or send to zbrush back and forth.

Unfortunatly, using many of dponts stuff often leads to crashes, I just tried particle paint in a pretty newly installed 64 bit version, instant crash when activating particle paint and selecting the emitter, and that was without even working in vpr.

kadri
11-04-2016, 01:28 PM
Are you aware of any terrain-modeling program with such capabilities? I've yet to run across one that supports such things.
I can't open the link right now but have a look at this video. You can export landscapes with overhangs from Terragen this way:

https://www.youtube.com/watch?v=bTKfAeEPDhY&feature=youtu.be
(from here http://www.planetside.co.uk/forums/index.php/topic,21311.msg213591.html#msg213591)

prometheus
11-04-2016, 02:24 PM
I can't open the link right now but have a look at this video. You can export landscapes with overhangs from Terragen this way:

https://www.youtube.com/watch?v=bTKfAeEPDhY&feature=youtu.be
(from here http://www.planetside.co.uk/forums/index.php/topic,21311.msg213591.html#msg213591)

Thanks, that is definitely interesting...good to know, though it does only deal with indents cavity carve in to ground, or overhangs as geometry, it has nothing to do with the question of erosion on parts with such vector displacement? unless you can combine that.

jwiede
11-04-2016, 02:26 PM
I can't open the link right now but have a look at this video. You can export landscapes with overhangs from Terragen this way:

https://www.youtube.com/watch?v=bTKfAeEPDhY&feature=youtu.be
(from here http://www.planetside.co.uk/forums/index.php/topic,21311.msg213591.html#msg213591)

The technique is useful, thanks, but not quite what I was asking. I was asking if there was any terrain-generation app that would automatically generate terrain with caves and overhangs, and properly accommodate them in its handling of erosion, etc. While TG will allow the user to create such overhanging geometry, it won't really do so for its own auto-generated terrain*, nor consider such when determining erosion behavior, etc.

*: While the auto-generated "fake rocks" created tiny overhangs associated with individual rocks, the terrain itself still didn't have any, nor were filters like erosion impacted by the fake rocks' overhangs (AFAICT). The technique you cited is still very useful, no question, but TG's terrain manipulation is ultimately heightfield-based, and thus neither creates nor considers caves/overhangs.

@prometheus: Voxelogic's Acropora (http://www.voxelogic.com/index.php?option=com_content&view=article&id=1&Itemid=21) apparently CAN generate "terrain" with caves/overhangs, but has only very basic/limited ability to "naturalistically generate" such features (iow, no erosion, etc. instead just uses noises, albeit nice-looking noises in many cases).

kadri
11-04-2016, 02:38 PM
There is an erosion plugin for Terragen:
http://www.planetside.co.uk/forums/index.php/topic,20752.0.html
You will have to wait a little for a new version specially for Terragen 4 as Matt said in page 11. But it works.
You can import of course anything you want from World Machine, World Creator etc. to Terragen and export ones again.

kadri
11-04-2016, 02:48 PM
But i haven't tried erosion specifically on overhangs so i am not sure if it would work in that case as required.

kadri
11-04-2016, 03:35 PM
I just got curious and tried it with a file that was posted in the Terragen forum somewhere.
You can see the bare EXR vector displacement file and the eroded one (with the Terragen plugin) and in the last i merged the two ones.
Please be aware that this was just a 10 minute test.

jwiede
11-04-2016, 05:14 PM
I just got curious and tried it with a file that was posted in the Terragen forum somewhere.
You can see the bare EXR vector displacement file and the eroded one (with the Terragen plugin) and in the last i merged the two ones.
Please be aware that this was just a 10 minute test.

That kind of highlights the issue, the erosion shown clearly did not consider the overhang, but instead uniformly eroded as if all were equally "exposed".

prometheus
11-04-2016, 06:06 PM
The technique is useful, thanks, but not quite what I was asking. I was asking if there was any terrain-generation app that would automatically generate terrain with caves and overhangs, and properly accommodate them in its handling of erosion, etc. While TG will allow the user to create such overhanging geometry, it won't really do so for its own auto-generated terrain*, nor consider such when determining erosion behavior, etc.

*: While the auto-generated "fake rocks" created tiny overhangs associated with individual rocks, the terrain itself still didn't have any, nor were filters like erosion impacted by the fake rocks' overhangs (AFAICT). The technique you cited is still very useful, no question, but TG's terrain manipulation is ultimately heightfield-based, and thus neither creates nor considers caves/overhangs.

@prometheus: Voxelogic's Acropora (http://www.voxelogic.com/index.php?option=com_content&view=article&id=1&Itemid=21) apparently CAN generate "terrain" with caves/overhangs, but has only very basic/limited ability to "naturalistically generate" such features (iow, no erosion, etc. instead just uses noises, albeit nice-looking noises in many cases).


Thanks for the links, interesting, will have to take a look, if we first of consider generation of overhang cliff/ rocks..without going in to eriosion, I havenīt seen anything either, not sure though how it was with the newest vue, will have to check.

otherwise I would simply mask areas with alphas if I am using lighwave only and then use some procedurals in normal direction, it wouldnīt generate overhangs that also have stalagmites going down benethe the overhang, for that I guess we would have to sculpt, but considering tasks like this, I would probably just use blender and sculpt with the grab brush with enabled dynatopo, itīs great for creating new overhangs or bulging areas, and it does so with the detail pix level you set to get a good quality, and if you get to much detail/polys, you could just turn of the brush strength but still use the standard brush and paint brush the area with lesser pixeld detail, that will reduce the polys, or increase if you got to low polys..so thatīs something I love about some of blenders sculpting tools, feels smoother to work with than sculptris actually.
You also got peak, fill and deepen brush tools.

You could also load an erosion map and sculpt with anchored brush and drag over an area of a rock pillar for instance and get a cool look, it wonīt follow proper physical erosion though so itīs a fake.

I did fiddle a bit with particles flowing down a rock in ligthwave, and getting that right was no issue, but as soon as I used particle paint, always crashing...I tried with some node hack but crashing there as well, so I gave up trying to retrive som splat map from particle that way...sure it can be done though if you do not encounter crashes.

kadri
11-04-2016, 09:03 PM
That kind of highlights the issue, the erosion shown clearly did not consider the overhang, but instead uniformly eroded as if all were equally "exposed".

Depends on which kind of rock-erosion you want. For me this is a good start (look for eroded rocks with Google for example).
But it looks like you want a different form, like your link with the Acropora ( software looks interesting, thanks). Yes that kind of erosion is harder to do.

Marander
11-05-2016, 05:13 AM
Are you aware of any terrain-modeling program with such capabilities? I've yet to run across one that supports such things.

http://www.e-onsoftware.com/products/vue/vue_2016_xstream/?page=terrains

There's a sculpting video that shows overhangs.

prometheus
11-05-2016, 07:45 AM
http://www.e-onsoftware.com/products/vue/vue_2016_xstream/?page=terrains

There's a sculpting video that shows overhangs.

yes I knew you can sculpt overhangs vue...which you can perform in many other programs using sculpt..like blender, and it probably maintain erosion, though I am not sure that would be a correct erosion based on the actual overhang, since it just maintains the erosion from the former shape.
they have worked a lot on the terrain editior so there is some nice stuff there, also a new retopo function so elevated areas will get more poly detail at a cliff side for example without just getting stretched.


thereīs still no terrain software actually generating the overhangs itself without the need to sculpt and then adds erosion, unless the voxel softare jwiede linked to can do that well.

Michael

jwiede
11-07-2016, 07:40 PM
thereīs still no terrain software actually generating the overhangs itself without the need to sculpt and then adds erosion, unless the voxel softare jwiede linked to can do that well.

Just to be clear, AFAICT, Acropora doesn't support proper "erosion". It's fine for generating organically-formed-looking shapes including overhangs, caves, etc. but for adding erosion, etc. you would need to move into another program.

Interesting, there really don't appear to be "commercial" terrain generation packages which support erosion and similar "simulated" geological effects on concave geometry structures (AFAICT). I can kind of imagine why: The wind/water erosion simulations would be incredibly compute-costly to track 3D flow patterns, etc. at accuracy level needed for concave 3D structures like caves, etc. It also requires much, much greater understanding of material compositions, etc. to determine how erosion will behave in those environments.

I've started thinking a bit about how one could reasonably cheat a bunch of that, but it's a LONG ways from anything practically usable.

prometheus
11-07-2016, 10:48 PM
Just to be clear, AFAICT, Acropora doesn't support proper "erosion". It's fine for generating organically-formed-looking shapes including overhangs, caves, etc. but for adding erosion, etc. you would need to move into another program.

Interesting, there really don't appear to be "commercial" terrain generation packages which support erosion and similar "simulated" geological effects on concave geometry structures (AFAICT). I can kind of imagine why: The wind/water erosion simulations would be incredibly compute-costly to track 3D flow patterns, etc. at accuracy level needed for concave 3D structures like caves, etc. It also requires much, much greater understanding of material compositions, etc. to determine how erosion will behave in those environments.

I've started thinking a bit about how one could reasonably cheat a bunch of that, but it's a LONG ways from anything practically usable.

Yep..thatīs what I ment in my statement, though the sentence meaning got lost when I finnished with arguing about erosion.

I tried to fiddle with particle, and it wasnīt that I couldnīt get particles as I wanted...or that they were slow, it was the fact that particle paint always crashed that prevented me from looking in to retreiving a procedural paint from that and then trying to bake it out for displacement.
I tried fiddling with nodes as well since particle paint crashed all the time, but it crashed anyway..so I gave up.

Michael