Dunes and sand mask / Removal or sand in / Height and inverted height / Road in tex- road tex difference(s)

[MarcSaunier]

@Kosvid Hello,

I’ve been looking closely to your Help file ( G3 E.A.Road texture / Dunes - #23 by MarcSaunier now closed as solved):

• Thank’s to you I could make a simple project with Terrain + Road + Dunes, each with its own texture and dunes covering part of the road here and there:

• About the sand mask:

Sand outpout into a fx with a .0001 threshold works fine.

Sand output into a fx with Autolevel and strong on + a little Multiply and Shaper tweakings works fine too.

• You use a height node into “Sand in” to define where Dunes are visible.
  Is this a personal preference or is there another reason why you don’t use “Removal” instead ?

• I tried using “Removal” and so plugged in an inverted Height mask.
  It looks like the inversion isn’t correct:

Do you have any idea why ?

• Finally, I imported a texture for the road using a file node and plugging its out into “Road in Tex” : OK or " Road Tex" : OK too.

Do you know what’s the difference(s) between Road in Tex and Road Tex ?

[Kosvid]

Hello. :)

Sand output into a fx with Autolevel and strong on + a little Multiply and Shaper tweakings works fine too.

I avoid using Autolevel as much as possible in case I want to export something at 16K or higher, since it breaks masks during subdivision process, as each tile gets autolevelled separately. But for the mask not to be too harsh, after Threshold you can set Blur to some slightest amount like 0.001-0.003.

You use a height node into “Sand in” to define where Dunes are visible.
Is this a personal preference or is there another reason why you don’t use “Removal” instead ?

You can say both? There’s a strong reason behind it, when you use it as “Sand in”, the mask just treats the white spots as a spawning point (to be honest, that’s the behaviour I would personally expect from “Emitter” input, but I just use what works for me), from where the simulation goes.
Try plugging height of some terrain into “Sand in”, set the duration to max, and play with the wind azimuth. Then do the same but with the height plugged to Removal - you’ll see the difference, it won’t feel natural. It just cuts off the result, instead of being the base for simulation. And hence it looks unnatural to me for general case, so one could call it a personal preference, but I’d say it’s rather obvious why when you can compare. :)

inverted Height mask looks like the inversion isn’t correct
Do you have any idea why ?

I think it probably has to do with mask enhancement. Do you have anything picked here?

Other than that, I don’t know.

I imported a texture for the road using a file node and plugging its out into “Road in Tex” : OK or " Road Tex" : OK too. Do you know what’s the difference(s) between Road in Tex and Road Tex ?

Just tested it. “In Tex” eats any incoming texture as the base.

Road node preview without it:

Road preview with it plugged:

Thus I surmise “Road Tex” adds texture only to the road itself.

[MarcSaunier]

Thx a lot for your answers !

• mask enhancement set like this:

@Kosvid

Try plugging height of some terrain into “Sand in”, set the duration to max, and play with the wind azimuth. Then do the same but with the height plugged to Removal - you’ll see the difference, it won’t feel natural. It just cuts off the result, instead of being the base for simulation.

I tried, but because my inverted height mask isn’t the exact opposite of the non inverted mask, I had to tweak the fx modifications options => closer but not exactly opposite => Dunes’ s visible surface not exactly the same + Even at 1K Dunes node is very long to perform here. It makes it hard to compare => I have not really been able to see the difference. And certainly, my eyes are not trained enough to notice.

Anyway, asking differently: In which occasions would you use Removal ?

@Kosvid

Thus I surmise “Road Tex” adds texture only to the road itself.

Yes, results were “OK” in both cases checking the road node only.
But OK only if the texture file is plugged in “Road Tex” checking the final combine.

[Kosvid]

@MarcSaunier

Even at 1K Dunes node is very long to perform here

Oh, yes, I saw that in some other topic but forgot to write to you about it.

Please go to Preferences - Compute and make sure you GPU is enabled. To me Dunes took 30 seconds to calculate when the GPU was off (same for other simulation nodes like Thermal 2 and Erosion 2), with it on, my Dunes usually take less than a second to get built.

Well, maybe you have a really old GPU, but I would check anyway.

@MarcSaunier

I tried, but because my inverted height mask isn’t the exact opposite of the non inverted mask

Could you send a file with the two nodes, normal height and “falsely inverted” height? I’d take a look if it persists on my side.

@MarcSaunier

I have not really been able to see the difference. And certainly, my eyes are not trained enough to notice.

This should demonstrate my “spawn area vs cut-off post-simulation” point very well.

@MarcSaunier

Anyway, asking differently: In which occasions would you use Removal ?

When I deliberately want something to be clean from sand. Most likely it’s something in the middle of the dunes.

[MarcSaunier]

@Kosvid

make sure you GPU is enabled.

Bingo !..
Dunes node is now very fast here.
GPU had always been enabled before installing G3 EA. I didn’t even notice that it was off after the installation. My bad.

@Kosvid

This should demonstrate my “spawn area vs cut-off post-simulation” point very well.

Thank you for the time spent. I now indeed clearly see the difference !

@Kosvid

Could you send a file with the two nodes, normal height and “falsely inverted” height?

Here is one

Height normal_inverted.terrain (8.1 KB)

[Kosvid]

Sure, you’re welcome.

As for the file, I checked it. Indeed it looks “asymmetrical”. My first thought was to blame human perception, as in, inability to tell apart close tints of really bright greys, but looking at that spot in the corner where the mismatch is so obvious, I think it has something to do with actual display.

I think I’ll send a report about that.

If you switch to “Hot” or “Spectrum” mask display, you’ll be able to see intermediate tints much better. I’ve used “Hot” since Gaea 2 so I wasn’t aware of the problem. As for the nodes, they act as they should, so inversion does just invert the parameters properly. It’s the display that’s skewed.

[MarcSaunier]

@Kosvid

I think it has something to do with actual display.

I think that you are right.
The difference is much less obvious using “Hot” or “Spectrum” than with other options:

If it’s worth a report, just let me know; I’ll take care of it, you already spent enough time on my case !
And then I’ll close this thread as “solved”.
Thank you again for all your answers and help files !

[Kosvid]

I sent the report with a demo video and your file soon after typing my message. =)

Thanks for the contribution!

[MarcSaunier]

Thanks again to you for the clear help and time spent !
I might come back (on a new thread !) for… tintintin Triplanar node and cliffs !

[Kosvid]

…Welcome, but I believe you’re supposed to mark as the solution the message that answers the original topic the best, since it gets pinned right under the first post, so people don’t have to scroll down to it. :D

[MarcSaunier]

Well… Old poops, you know how they are