View Full Version : Melting snow, growing moss

05-05-2014, 11:51 AM
I saw somewhere that the Dented texture could be used to grow moss, but this was when using the old Texture editor, not nodes, where the settings are different.

Currently I'm using a Crumple node to create patchy snow scattered over the ground. I want to 'grow' it in reverse to show it melt. After the melt, I want to grow moss in a different pattern over the same ground.

I've been using the same Crumple node for both purposes, but the only way I can figure out how to subtract the snow, or add the moss, is by gradually changing the Alpha of a Gradient that's plugged into the Fg Color of a Mixer node, then into Color B of Etched. This works, but looks bad because everything disappears, or grows, at the same time, which is in effect a fade off or fade on, not 'growth'.

Would someone point me in a better direction for this?


ps it's always right after posting that I see things more clearly. In this nodal tree it's the Etched that has to be changed, not the Crumple. In any case, I don't understand how to grow a procedural from invisible to visible.

05-05-2014, 01:15 PM
You could feed the output of your crumple node into a gradient node. Then you can envelope the keys for the position of the points, not the alpha. This can make the texture area grow or shrink.



05-05-2014, 06:25 PM
Thanks lertola2, I apologize for not being very clear. These jpegs basically represent my scene's setup. I want to maintain the underlying texture, the Dots in this example, without changing it at all. On top of that texture, I want to 'grow' the blue & white Crumple texture backwards, to make it disappear like melting snow. After that, the ground will be bare, only showing what is here represented by the dots. After a couple of seconds of bare ground, I'd like to use the same nodes to grow random areas of moss as the next overlying texture (not in the same pattern as the snow, of course). Changing the Gradient's Position param won't help with the nodes I've got here.

I experimented with Enveloping the Corrosion parameter of the Etched node. When its value gets to 6.5 the 'snow' does disappear, but along the way the various shapes of the texture jump all over the place. I'm wondering if there's a texture that can be Enveloped using nodes, and while it's growing, its 'shapes' change volume, but maintain their relative positions, so the snow or moss or whatever, is not arbitrarily moving from one distant part of the ground to another as it grows, or disappears, as the case may be.

05-05-2014, 08:09 PM
I will not delve deeper in to how to for this actual effect..but I just wanted to say that you can use the "old" dented procedural texture in nodes too, in the node edtior...just add Layers/color or scalar layer..and double click to open that layer and add the dented texture from there inside of nodes..from there you can at least get the color or alpha output from the old texture and feed it in to other node inputs.

But yes...we could use a dented node version too, since it is missing.


05-05-2014, 09:08 PM
Greg, I do not know what the etch node does. It looks to me like if you took that out you could do what you want with the gradient node and mixer node. If you animate the position of the key in the gradient you hide or reveal more or less of the dots texture.


05-06-2014, 03:21 AM
Here's a quick test I did:


And the nodes:


The divide node sets the speed of the moss dieback, and the scalar sets the maximum coverage, just play with it and you'll see what I mean.

You could use other textures than Turbulent noise, it was just what I grabbed first.

05-06-2014, 05:52 AM
Whilst waiting for the glue to set on a speaker recone, I had another play:



Standard subdivided deformed landscape. Basic ground texture going into A, basic snow going into B, and the alpha is driven by another texture, (you can get as complex as you like here, set it the same a s the displacement to get the snow melting from lower ground up, or possibly even get a bit canny and use a spot info node so it melts in direct sunlight first. I need to think about that one a bit more... :)). The important bit here is the Gamma setting, you can change it to give a softer or harder edge to your snow, and the phase is driven by a D+BW time node to expose a varying part of the waveform. Much more elegant than the previous version.

The blue link up to the bump input was just a quick experiment to get a bit of depth to the snow. Needs more work ;)

edit: tweaked the lighting and surfaces a little to clarify things, and set a longer render going whilst I fix this other driver. Pop back in an hour or so to see it.

05-06-2014, 07:52 AM


05-06-2014, 10:00 AM
One of my old tricks is rather simple and silly but I place another mesh layer conformed to the terrain or item, then scale/move it down and out. Using occlusion in the shader to help the soft edge/blend effect as it "melts."

05-08-2014, 01:07 PM
Thanks everyone,

In my scene, I have duplicated the Crackle node tree that I used for ground displacement, and used it for the ground texture, so the Crackle plugged in to Etched Color A has to stay. I want to keep the IFW2_Etched node in because I like the patchy snow pattern it produces. At this point, I really don't want to slog through the process of trying to find another node that delivers a pattern I like.

pinkmouse, your examples look really cool. I got your setup with the divide node working, though I don't see how you got it to melt the snow, I could only figure out how to grow it. That will work if I reorganize the rendered frames in reverse, but I'll have to modify the scene to be sure nothing else is going on during the time the snow is melting. It would be better if I knew how to start with the snow in place, then melt it, as you did. The trouble may have something to do with my need to use the Etched node, which only has a 'Blend', and not a 'Function' input. In this setup, the Scalar node plugged into Clamp High only serves to fade on the snow, so I don't use it in this way.

I see that as an artifact at the beginning of the anim, the Gain also fades on the snow until its spline reaches the diagonal. After that, its effect is to grow, and increase the snow's coverage. Again, I suppose that this is because of the Blend input. I plugged the Scalar into Phase, and Enveloped it beginning at zero. In the last ten frames its value rises until it reaches .3, which makes the snow completely cover what little background is still showing at that point. Not sure how to control the time. I start with Divide at 25, then on frame 25 (when the Gain spline reaches the diagonal), I set the value to decrease to 10 by frame 120. I just now noticed that my key on fr 25 doesn't have Tension set to 1, so there's an unwanted 'bump' between fr 4 & 25. Oops.

The Material nodes were giving me fits. I couldn't figure out a way to modify the trees to get them to work while still keeping the Crackle and Etched nodes in. Lots of food for thought in your example, and suggestions! I'll be working on those things.
Michael, thanks for the reminder about using Dented through Layers, I forgot about that. The drawback for me was that in using the old Layers system, I couldn't figure out how to add texture to the snow part, it appears as just plain white. I tried adding a procedural and Alpha layer, but couldn't get the effect I wanted with Noise procedurals, only with Checks, and such.
Lertola2, with my setup, manipulating the Position only changes the brightness.
Mr_Q, I am using that same idea to melt ice into water puddles by morphing a blue plane that underlies the ground displacement. That was sure a pain to set up! :)



05-08-2014, 03:27 PM
Greg, ignore the first version, that was a bodge, the second nodal setup is the one you should be emulating ;)

If you can post your scene, (or at least the ground part of it), I'll have as look at it for you tomorrow. I'm doing some more reconing, so will have "glue time" to have a play.

05-08-2014, 06:01 PM
Thanks pinkmouse! I'd learn a ton from Materials.

These are the first textures and displacements I've done that have any degree of sophistication. Before this, I'd only created Layered textures that were very, very simple. I'm sure there's redundancy in the nodes that feed the Crackle node, but the surface looks good enough, so I didn't want to mess with it. But I'm not 'married' to any of it, either.

The idea of the animation is that first, the blue-white snow melts. Then we hold on empty ground. Finally, from the same nodes (since I assume that would be the easiest way to handle this), green moss grows in a different pattern than the snow. Also, as the snow melts, an underlying object morphs (frames 296-447) to appear as puddles of water. The transition between the three states of the ground is handled by the Alpha of the Gradient node, Enveloped to fade off the snow between frames 205-356, hold on empty ground between 356-400, then fade on moss on between frames 400-550. OMG, 'Growing' the snow and moss would look so much better than the fades!

I use Sunsky for my lighting, so the snow has to be blue-ish. Under Sunsky in this scene, white renders with a rosy hue. I removed the fog, other elements, and everything not directly related to the ground, except Sunsky--oh, and its Turbidity is Enveloped.
The main foreground texture is 'pingo_nAll'. The little hill (pingo) is separate, and textured identically to the foreground. 'active_layer' is the area in the middle distance, the vertical face of the cliff, and the horizontal ground above and below it. 'background' is the distant hill. I screwed up something in the Enveloped transition of the background after the snow melts, so the hill darkens abruptly. That will need my attention too.

This is so cool, for you to help me with the actual scene!