I'm gonna be blunt here. I haven't got a clue about "intersect underlying".

[Jgone]

I have been really avoiding snowy renders for the past years because i just can't make the snow look like this : https://isorepublic.com/wp-content/uploads/2017/07/winter-snow.jpg
All i get is a completely random mess that looks pretty much horrible.

I have asked questions on the forums, used the search function etc.. and yet i have never gotten a good snowy render. So i'm gonna be real needy here and hope people don't hate me after this :

Could someone explain to me in detail what each of the sliders do ? Intersection zone/shift/ min intersection shift ? Which one i should use ? Displacement intersection ? Favor rises/depressions ?

As you might have seen, i'm not a native speaker so that might also contribute to the fact that i can't quite get the grasp of this effect.  I'm fairly sure after all that this "setting" is the bees knees when it comes to those beautiful snow renders. Correct me if i am wrong.

[luvsmuzik]

Those functions are used when adding a surface layer Jgone.

For the particular image you mention:

Restrict you snow by altitude and slope degree usually works fine. Then you can adjust with intersect underlying if your snow does not "pop" the way you want it to. Observe in your render preview and see how the render triangles change color with each adjustment. The little blue square (upper right corner) on the surface layer component is also useful to preview changes.

[archonforest]

Perhaps u can upload your tgd file so someone can see the settings and do some changes. Thus u can see what settings are applied.

[luvsmuzik]

This post has two wonderful file shares for realistic snow:

http://www.planetside.co.uk/forums/index.php/topic,23243.msg235493.html#msg235493

[Jgone]

Those functions are used when adding a surface layer Jgone.

For the particular image you mention:

Restrict you snow by altitude and slope degree usually works fine. Then you can adjust with intersect underlying if your snow does not "pop" the way you want it to. Observe in your render preview and see how the render triangles change color with each adjustment. The little blue square (upper left corner) on the surface layer component is also useful to preview changes.

Altitude and slope degree are what i have been working with but i can't achieve.. "living" or "random" looking snow placements. It looks unrealistic when i try to do it. I was certain that the intersect underlying would be the key.
Thank you for the tips tho ! The little blue square really helps me out,  not sure why i never decided to click it.

Perhaps u can upload your tgd file so someone can see the settings and do some changes. Thus u can see what settings are applied.

I'll be sure to do this when i next time open terragen and seriously start working on it. I have already gotten some useful tips and can't wait to put em to good use !
Perhaps u can upload your tgd file so someone can see the settings and do some changes. Thus u can see what settings are applied.

This post has two wonderful file shares for realistic snow:

http://www.planetside.co.uk/forums/index.php/topic,23243.msg235493.html#msg235493

Thanks ! Will take a good look !

[Dune]

When using displacement intersection, the compute terrain patch size also has a tremendous effect on smoothness of the snow. The larger the patch, the smoother the 'intersected' area is calculated.

[luvsmuzik]

Awww....my wiki link says FrankB's  video tut about intersect underlying is gone! I have had that forever.

[Jgone]

When using displacement intersection, the compute terrain patch size also has a tremendous effect on smoothness of the snow. The larger the patch, the smoother the 'intersected' area is calculated.

Interesting.

Awww....my wiki link says FrankB's  video tut about intersect underlying is gone! I have had that forever.

This could have been a game changer .. Any way to find it ?

[cyphyr]

You can create a second Compute terrain with a larger patch size as below

[luvsmuzik]

Geek at Play TG3 shaders overview....does not go much into intersect, but shows layer techniques.

https://youtu.be/hILSY4VTd60

Another....a little more complicated
https://youtu.be/lmiWwj3Q2b0

[Jgone]

You can create a second Compute terrain with a larger patch size as below

Thanks for this, will take a look !

Geek at Play TG3 shaders overview....does not go much into intersect, but shows layer techniques.

https://youtu.be/hILSY4VTd60

Another....a little more complicated
https://youtu.be/lmiWwj3Q2b0

That second video helped a ton ! I now have a better idea how i can tackle the snowy scenes with the image map shader as mask on a surface layer ! Thank you

[N-drju]

To be blunt - I never really use this option, because yes... it is terrible.

I have some old snow presets from dandelO where this option is checked but I always uncheck it for the reason you mentioned. Just lately I found a good use for "intersect underlying" but still use it on a very, very limited basis.

[Jgone]

Okay so i have made some progress, this perhaps is not the best one i have achieved so far but doesn't matter. Does anyone have a trick how to make the snow look less spotty ? Rather large chunks here and there than gazillion small chunks ?

I created this with surface shader -> image map shader as mask (same as heightfield) + intersect overlay / slope constraint.


https://gyazo.com/dd970aa29dac82308d818789d15e7b39 snow layer settings

https://gyazo.com/3b69ae02dbc9e8a299cbfde170eb76da render itself

[luvsmuzik]

Okay, if I were to use intersect underlying here....I would favor rises and limit slope accordingly, with say 50-60 degree minimum.... Set altitude accordingly to range, using minimum (about half or third the maximum altitude of your terrain, leaving maximum set at default if you want snow caps. That way the snow layer should adhere to the edge of your slope....and your slope angle would be similar to...///////

If you want the snow to cradle in the depressions only......do the opposite, sort of....

If you are using a solid snow image mask this should work fine. If you are using an alpha type mask, (that looks like rivers branching out from solid white areas), your snow will not be even if you use restraints.  If you want to use that type of mask, you usually only have to limit altitude and stretch on a 1:1 ratio over terrrain.

[N-drju]

I'd go even further than that. Why don't you get rid of this item altogether and mask the snow with PF. This will give you much better control of the snow coverage. No need to complicate.

____________

Oh yeah, and luvsmuzik is right - favor depressions option is very handy if you want to create beds / bowls of snow, stones etc. Actually, it works pretty good as for something that simple.