Author Topic: Testing classic erosion on DEMs  (Read 266 times)

Offline bigben

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Testing classic erosion on DEMs
« on: November 13, 2017, 02:59:18 AM »
The one thing I like about having an erosion plugin for TG compared with creating TER + masks etc in WorldMachine is that you can apply the erosion after adding fractal noise to the DEM.. I'm starting my experiments with a 10m DEM from USGS.  The DEM already has good details but adding some more won't hurt. I'm looking for some generalised settings that I can apply to other DEMs.  Starting off with:
Size/Resolution = DEM resolution (16.000, 2048 for 10m DEM)
Erosion scale, Thermal effect size = 50% DEM resolution (5) ... guessing here ;).
Given the number of maps I'd like to use I'm guessing it may be better to use 2 erosion nodes, especially if creating rivers.  Off to play with masks...

Offline bigben

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Re: Testing classic erosion on DEMs
« Reply #1 on: November 13, 2017, 04:04:07 AM »
White level adjustment of Flow map. This map does not have a linear distribution so I typically use this with high gamma adjustments as well. For realistic masking I usually combine 3 variations with different white levels and gamma combined with slope and altitude masks to refine the distribution... it depends on what you masking. The flow map is also useful as an inverse map for masking ridges.

Offline Dune

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Re: Testing classic erosion on DEMs
« Reply #2 on: November 13, 2017, 06:56:39 AM »
The plugin has enormous potential, doesn't it. Nice example of the color adjust use, and good for users to see.
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Offline AP

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Re: Testing classic erosion on DEMs
« Reply #3 on: November 13, 2017, 07:36:46 AM »
Those are some interesting tests. I noticed some alluvial fans in some areas. Have you enabled the thermal erosion?

Offline bigben

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Re: Testing classic erosion on DEMs
« Reply #4 on: November 13, 2017, 09:07:30 AM »
The maps are very similar to those from World Machine (not surprisingly), but being non-linear I thought it would be good to demo the values required for various distributions.  I did enable thermal erosion on this as well but those talus slopes appear with just fluvial erosion with this terrain shape.

Offline AP

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Re: Testing classic erosion on DEMs
« Reply #5 on: November 13, 2017, 10:28:03 AM »
The maps are very similar to those from World Machine (not surprisingly), but being non-linear I thought it would be good to demo the values required for various distributions.  I did enable thermal erosion on this as well but those talus slopes appear with just fluvial erosion with this terrain shape.

So the fluvial erosion is both transporting and building alluvial deposits at the lowest slope points.

Offline bigben

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Re: Testing classic erosion on DEMs
« Reply #6 on: November 13, 2017, 10:32:42 AM »
So the fluvial erosion is both transporting and building alluvial deposits at the lowest slope points.

Yes

Offline blinkfrog

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Re: Testing classic erosion on DEMs
« Reply #7 on: November 13, 2017, 03:49:04 PM »
Interesting!
Try to set Erosion scale to 50 (if there will be too much of erosion - set duration or erosion strength lower) - it will be less gentle, but possibly more interesting. Although possibly it will be worse.

Daniil.

Offline SILENCER

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Re: Testing classic erosion on DEMs
« Reply #8 on: November 13, 2017, 04:20:16 PM »
The Map functions are pretty snazzy.
This is a great plug in.

I've been trying to figure over the last day out how to use the flowmap to mask a water shader, which has proven squirrley.
If you pull in tight enough, the idea is to use it to mimic a stone-filled stream, flowing downhill, without a lake object.

Offline bigben

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Re: Testing classic erosion on DEMs
« Reply #9 on: November 13, 2017, 11:15:47 PM »
Interesting!
Try to set Erosion scale to 50 (if there will be too much of erosion - set duration or erosion strength lower) - it will be less gentle, but possibly more interesting. Although possibly it will be worse.

Daniil.

Got a little distracted trying to make a river. Will try out some different scales to see what works best

Online bobbystahr

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Re: Testing classic erosion on DEMs
« Reply #10 on: November 13, 2017, 11:36:15 PM »
The Map functions are pretty snazzy.
This is a great plug in.

I've been trying to figure over the last day out how to use the flowmap to mask a water shader, which has proven squirrley.
If you pull in tight enough, the idea is to use it to mimic a stone-filled stream, flowing downhill, without a lake object.

Or try adding a 2nd Erosion shader and enabling Rivers which disables all other displacement and uses some of the other tabs adjustments...lok around and once you get some rivers happening just add the water shader to it's channel
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