CYCLES / Hair! (Strand Info node)

This seems to be fresh from the oven, still work in progress from the Blender Development Side, but if you like Blender Cycles and want to render some Hair Strands, then this is something cool you want to experiment with!

Light Emitting Hair Strand, it feels like dejavu all over again. This time it is in Cycles.

THE THREAD
I am actually just collecting some useful information from Blender Artist forum thread post on Blender Hair:
http://blenderartists.org/forum/showthread.php?274660-Cycles-Strand-Rendering

From that long thread, try and find a link to Blender Build with "Enable Cycles Strands" Option under the ParticleSystem as below:

NOTE:
If you cannot find the Cycles Strand Rendering option, try switching Feature Set to Experimental:

Also double check that you are in Cycles Rendering Mode.


Once you have the Blender Build with this feature and set everything, create some Particle Hair and render it in Cycles.

You don't really need to mess with Node Editor, the Hair Strand will render whatever Hair Particle you have and by default the Hair Material color is piped from the Object Material.

Only when you start to really develop the look of the hair, you may need to pipe in Strand Info node in the material.

Keep in mind that this is "brute force" method (instancing triangle mesh that goes the length of the strands), probably not yet fully optimized, but it is still pretty stable, quite fast preview especially when you render it in real time on 3D View. You can get nice frame render like 15 minutes per frame for full noise-free render. It depends on complexity really.

What really interesting is the additional Strand Info node that allows you to easily pass on data from Strand and really tweak the look of each strand.

STRAND INFO: Is Strand?

Looks like this is one way you can separate Material Color/Shader for the Emitter and the Strand. I am not 100% sure, but looks like this is one way to do it.

STRAND INFO: Intercept
Use Strand Info Intercept output with ColorRamp to ramp beginning and end Color along the length of strand.

The Intercept is also useful is you like to make the end of strand transparent to give softer look.

MIX SHADER COMBO

There are certainly unlimited way you can try and mix shaders for Strands. All the possibilities, including the OSL shader you can apply to it.

Colorful Furball.

UV Image Texture

This works right away, all you need to do is just apply Image Texture and UV like usual. All the color information will just transfer to each hair strands.

Big number Width Multiplier (grass like)

Small number Width Multiplier

ONE MORE THING ...

Dynamic Paint and Blender Particles Hair. There is still a gap between these two. Dynamic Paint goes really far already, while Blender Particles (with Node Editor and node workflow) is catching up. Can't wait until these two really connect, talk and fully blend with one another.