lets start at the beginning - how do blending shaders work?

[shadowphile]

I've been getting great help so far, but I find I'm still short on understanding when it comes to the blending functions.
The Heightfield shader is a good example.
It has three sources of, er, shading.
-the input
-the heightfield
-the fractal detail (if enabled)

Without a blending shader, I can see how the fractal detail is overlayed on the heightfield, and how the result is overlayed on top of the input.  If enabled, color will be overlayed, albeit a simple constant unless one of the 'shade by' options is selected.

Now I wire some complex shader into the 'blend by shader' input.  That input contains color, displacement, altitude, slope, roughness, whatever.  How do I determine how that shader influences the blending of the input and heightfield shader parameters?

If you want to also explain how the 'blend by heightfield' works, I'm all ears because I'm clueless.  I would try things for myself more, except tweak and render is SO slow and hit and miss...
thanks,

[Mandrake]

You worded this perfectly!! Bravo!! But, alas this is an experience answers..
My best answer to all of the above would be to  download some tgc ans investigate the nodes in question...

Difficult when all the nodes are already in place.. have you followed the tutorials available in these parts? You can see things from the ground up.
Kenny

[Henry Blewer]

Here's a link to the best power fractal tutorial I have seen posted.

http://forums.planetside.co.uk/index.php?topic=2287.msg22357#msg22357

It may help. It did me, though I find myself rereading it often. More makes sense after trying things out.

[shadowphile]

njeneb: that's a powerful tutorial, will have to give that a very close follow, thanks!

This really belongs in a tutorial list somewhere.
What I keep wishing is that there is a sticky list of threads, grouped by function, so that newbs like me can FIND these threads.  Each time a veteran explains the basics of how a particular node works, the link to that thread should go into a doc of some kind.  Would be easy to update and make the issue of basic documentation less so. (an issue that is)

[Henry Blewer]

I have been thinking along the same lines. It would be a lot of work.
My other thought was improving the search function. That would be at the discretion of the forums software programmers.

[Oshyan]

The Blend Shader inputs work basically like a mask or alpha channel. It will look only at the brightness values of the incoming node and use that to control where the blended shader appears, with white as "fully visible" and black as, of course, not visible.

The Shader input is actually for creating a heightfield from an existing shader network, for example if you want to rasterize and then save a cool terrain you've made with procedurals, you'd plug it into the Shader input, set the heightfield's size, generate it, then right-click on the node and Save As.

The coloring functions built in to the heightfield node are mostly for testing or special circumstances and needs. They're certainly not where you'd want to begin applying color. For that you'll want to be in the Shaders layout/group, after the Compute Terrain that ends the Terrain node group. The Base Colours node overrides all previously applied color by default. You can of course disable it, but it's generally advised to do your terrain displacement in the Terrain group, and your texturing in the Shaders group.

The search function is about as good as you'll find on any forum, I reckon. And in any case there's not much we can do to improve it as we're at the mercy of the forum software and plugin others.

As for where to store tutorials, the Wiki is the ideal place! And still very underutilized in my opinion: http://www.planetside.co.uk/wiki/
Anyone can login with their normal forum credentials, and anyone can edit. I encourage people to add any useful info they find.

- Oshyan

[Henry Blewer]

I'll be modifying the Blender object post as I learn more. After work tomorrow I will save he thread into notepad and see if I can make it better. (at least more useful. Perhaps with images?)

[shadowphile]

aha!  So all the non-luminance info on the blend shader input is ignored, which is easy because that is just like a normal alpha mask operation.  My lifespan just lengthened...

Not sure why Oshyan was referring to the 'create heightfield from shader' node...

I'll go back to the wiki...

[Oshyan]

Sorry, for some reason I thought you had asked about the Heighfield Generate and its inputs.

- Oshyan

[Henry Blewer]

Would not the power fractal tutorial apply for using the power fractal as a mask in a height field?