Snow on gree tree textures

Hansmar

Hi.
I made a tree for the Bryce4ever tree challenge at DeviantArt (http://fav.me/d6ghm74). Then I decided to re-use the tree with a different view. I wanted to create a tree that looked like a tree in Spring, that suddenly got some late snow.
I tried several options, e.g. some presented in tutorials by David Brinnen, such as those on filters in textures. First I came up with this:

And I was not very satisfied. Made the first one with a altitude filter included in a texture in the first channel, that also contained the white, a greenish texture in a second channel and an altitude filter in the third channel. I just could not get the grey to be white and I wanted some snow on the lower leaves too.

Then I used a trick: two trees, one with green texture and one with white, mixed so that there is less white than green. This is in the second picture.

Then I decided I need more light in the green parts and made those leaves slightly transparant by adding a channel with a fractal only for transparency. This increased render times substantially (also using IBL lighting, true ambience, blurry transmissions and soft shadows which might not all have been needed.

Does anybody have a better idea for getting this type of effect? Ideally with snow on some top leaves of a branch, but not (so much) on the bottom?

The terrain, by the way, is all in one texture, which worked out fine.

David Brinnen

Interesting challenge. OK here's an idea. Take your first example, your altitude controlled response and use that to control the level of specular response. Then set your specular colour to white, and your specular halo to 254, 254, 254 RGB values. And then create a very strong specular light source, with none for fall off and use the influence control to target only your tree. Put this light source right over your chosen tree. So what happens here, is that leaves at the top of the tree and facing the light source will turn white. Leaves lower down or facing away from the light source will show whatever colour you have set. This will potentially offer some kind of realistic bias that might look like snow - a bit - maybe, that's the idea.

If you post an image of the effect you are looking for and post me the sort of tree you want it to apply to, I'm happy to have a go at simulating the effect. I can't promise anything, but I will try. My email is,

mail@davidbrinnen.com

foleypro

Try using a Terrain texture that has snow in the texture then go into the texture lab and rotate the material until you find the right look...I have done this for quite a few years now...

Hansmar

@davidBrinnen. Thanks. That is an interesting thought. I never really played with specular yet. Should follow more of your tutorials, I guess. I think I'll give it a try, just to see what it does.
I must say, I don't have an example picture (except in my head). Type of tree doesn't really matter to me. Realistically, it should be one that is green in winter, because a tree full of green leaves with substantial snow is not something I see very often! ;-)

@ foleypro. Thanks too. Why didn't I think of that myself? Another option to try!

dwsel

My two experiments on that:
- a - metablobs scattered on a branches
- b - generated a heightmap from the tree and made boolean difference of that terrain and its duplicate
- ab - combo of these two

Sorry for a really quick reply, may post more details later if you wish.

Chohole

Tree duplicated and moved upwards just a tiny, tiny tad. Snow tex on leaves for 2nd tree,

David Brinnen

You've already got some good suggestions. OK, here's the idea I had to use specular response.

1. Wireframe sideshot shows an infinite width parallel light shining down on the tree.

2. Light settings.

3. Material settings of leaves. Note specular halo is set at full white.

4. Result.

Edit: used one of the "special trees" of Foleypro's here (but took out the additional bit for simplicitys sake) I recommend any of those trees they all have good shapes. Good work Brian!

Hansmar

Hi all,

Thought I would show you some update of my attempts.
First attempt is with the advice by David Brinnen on the use of specular and a light providing only specular. I did not actually save all the settings for this one (even though I am already at tree 15...). But I think I used some 'true ambience', leading to a rather washed out snow. First I thought I liked it, but then I decided: no.

Second attempt, I started to combine the two approaches of specular light and second raised tree. This attempt has a very slight shift and the two leave textures and the light setting (with true ambience) are shown.

Then I moved past an attempt I did not like afterwards.
But the last two options are quite nice, I think, with again shift of trees, one with snow and the other green, and specular light from above. Difference is the light settings.
I think the last two attempts really show what I wanted! I am happy!
(I did change the landscape and the trees a bit to enable modifying the camera position without seeing the horizon and to have a more open tree, where snow on lower leaves would be logical).

Thanks all for the advice. I would appreciate feedback!

Hansmar

Oops, only 5 attachments allowed, so here is attempt 3.

Hansmar

And the final attempt. I think I like the previous version just a bit better. Looks like in this version the snow is falling from the leaves....
Just one tree now with the specularity in the leaves.

I would appreciate feedback.