Snow Peaks - PF Altitude Constraint

[Hetzen]

This maybe of use for creating undulating snow peaks on mountains. The surface layer tends to create a very flat line when used on it's own to restrict a minimum altitude for snow on mountains.

Here is a simple clip file and scene that modulates that line to give a more natural effect. I've put the important nodes to play with within the Parameters Group. Altitude defines the start height of the mask, Fuzzy Distance Up, defines how far black travels to white ie soft blends. PF Altitude Modulation is the fractal that multiplies the PF Modulation Distance, so within the PF you set your scales of the effect, and use PF Modulation Distance to define how many meters up it moves the altitude mask line.

There's nothing stopping you playing around with the  noise tab to create different patterns, although the Y stretch is not a bad thing to leave as it is to keep a consistant pattern up your mountains.

Anyway, have fun, and hopefully we'll see more images of mountains that don't have flat lines around their peaks.

All the best

Jon

[Dune]

That is very kind of you, Jon. Thanks! Interesting nodes, as ever.

regards,

Ulco

[mhaze]

Thanks for this but how do you add it to a scene?

Mick

[Hetzen]

Hi Mick

I've attached a .tgc file in the above post, which contains the relevent nodes in a clip file. To use, go to /File/Insert Clip File and the nodes will apear in your scene, you just then need to use the output of the last node in the group to plug into your snow surface layer's blend input (at the moment its attached to a sample surface layer).

Thanks Ulco, with a little imagination, you can use two of these to create an altitude band between two altitudes. Use one to set the highest limit, then use a Complement Scaler node to inverse the output, then with the second you define the lowest altitude, Complement Scaler that output, then subtract from the first group. Change the seed in the PF to get different variations with the two limts, and you've got an interesting tree line mask.

Cheers

Jon

[mhaze]

Cheers

I'll have a play

[pclavett]

Hi Hetzen

Thanks for sharing this very interesting tgc ! Unfortunately when I open and insert it, it is not plugged to anything and TG2 relates that "a linear step scalar" is unknown and not found. I am including a screenshot of the tgd as it is opened and the relating nodes. Hope you can help me with this as I am really interested in this modulation of the snow line. Thanks a lot for your sharing !

Paul

[Dune]

Jon is working on an alpha, that's maybe why, but you should attach like here.

[pclavett]

Hi Dune

Thanks for the advice but I do not even have a "linear step scalar" in my TG2.....and the software is up to date !!! Maybe there is something that I am missing here !!! Thanks !

Paul

[pclavett]

Hi Again

Have been to the documentation at Wiki and find no reference to a "linear step scalar" but it kind of looks like a "smooth step scalar" in a text version....are these interchangeable Sorry for being annoying about this....but this is the only way to learn !!! Thanks for your patience !

Paul

[dandelO]

Hi, Paul. What Dune is saying is that Hetzen has shared, for some reason, a clipfile containing a node, the linear step scalar, that is only available in the alpha version of TG that he is using.
This node doesn't exist in the current public release of TG2 so it won't work for anyone who isn't running the alpha versions that contain it.

[pclavett]

Thanks DandelO for the information....and also Dune for that matter.....just fell on stupid ears...mine !!! Now I know what Alpha means ! Appreciate all your input guys !

Paul

[Henry Blewer]

I am happy to hear about a new function. I have not been render so much lately as playing around with blue nodes and atmospheres. I am so close to putting the system together, I am not very patient for the render times on the Pentium HT system I have now...

Thanks for sharing this. I use a couple surface layers now. One for the main snow areas. The other uses a distance shader with an overhead camera. A power fractal is used as a color mask in the blend by input of the 2nd surface layer. The distance shader controls altitude and the color offset controls coverage.

[pclavett]

Hi Hetzen

For the sake of experimenting, I have used a "smooth step scalar" instead of the "linear step scalar" and obtained similar results...at least they look similar. I have used your node on a work that I am in the process of completing and the results are much better than I had obtained before....looks much more natural with loss of the straight horizontal lines that you get with altitude restriction alone. I am including a test render of the snow on the work that I am doing with 4 snow layers at different heights, all restricted by your complex with different settings and different powerfractals. I am also including a version of your tgc that was organized with an internal network to save some space. I hope you don't mind me doing that.....and it does work with the run of the mill TG2 !

Thanks so much for your help !

Paul

[Hetzen]

Hi Paul

Sorry, I've not been to forums for a while, so I've missed this. Also, my appologies with using the linear step function, I wasn't aware that this wasn't in the public release. You were absolutely correct that it's very similar to the smooth step scaler, except that the linear step creates a flat ramp from 0 to 1, where as the smooth step, curves out of 0 and curves into 1. All that will happen is the 'fuzzy zone' will be more condensed.

I'm really pleased that you're finding it usefull and the results effective.

To create a maximum limit from the above, just put a 'compliment colour' node after the Smooth Step Scaler. This will invert white to black, thus making everything below your set altitude white.

To create a modulated altitude band for say strata, or a tree line population, insert two of the clip files into your project, set one to your lower altitude limit, 'compliment colour' that output as before. Set the upper limit in your second node stack, and then use a subtract node to take this value away from your lower limit stack.

I'll update my files later on this evening.

Cheers

Jon

[Hetzen]

Here's a band version of the above node network....

It's not quite as I described as above, because you can drop the 'complement colour' node to make this a little more efficient.