Reflective hair

[thanaras]

Hello guys!

I would appreciate if you could help me on that: i want to render hair to be very reflective, for example like a christmas tinsel. Is there any way to make it look more shinny and reflective with the existing shader? Any other ideas? Cheers guys.

[old school]

Don't use the hair shader.

First off, in H11 on the object that contains the curves to render as tinsel, make sure to enable the option:

Render > Dicing > "Shade Curves As Surfaces"

This will render the curves as flat ribbons at a given width. The width is determined by a point float attribute called "width".

The orientation of the ribbon is by default pointing at the camera but you can override that by adding a point vector attribute called "orient". You can have twisting bending ribbons by manipulating the orient vector attribute.

See the attached file.

tinsel_test.hip

[hopbin9]

That's cool.

Merry Christmas!

[thanaras]

Thanks a lot old school! Its very helpful!

[thanaras]

Hello,

Back to the subject of the tinsel, I have another question. When I render the file that Jeff sent, for multiple frames, with a slightly moving camera, I get a crazy flickering in the specular highlights. Is this the way it's suppose to be, or is there any way I can get rid of the flickering? Thanks!

Don't use the hair shader.

First off, in H11 on the object that contains the curves to render as tinsel, make sure to enable the option:

Render > Dicing > "Shade Curves As Surfaces"

This will render the curves as flat ribbons at a given width. The width is determined by a point float attribute called "width".

The orientation of the ribbon is by default pointing at the camera but you can override that by adding a point vector attribute called "orient". You can have twisting bending ribbons by manipulating the orient vector attribute.

See the attached file.

[Macha]

First, there appears to be a mistake in the file. The orient attribute is a 1-float wheras it should be a 3-float or a vector (?).

Second, slightly increase the spec and reflect angles in the shader and/or increase sample in the mantra properties and possibly add motionblur. Perhaps smooth the orient attribute.

Does it still create flickers if you do that?

Hello,

Back to the subject of the tinsel, I have another question. When I render the file that Jeff sent, for multiple frames, with a slightly moving camera, I get a crazy flickering in the specular highlights. Is this the way it's suppose to be, or is there any way I can get rid of the flickering? Thanks!

Edited December 1, 2010 by Macha

[thanaras]

Thanks Macha. Yes it is still flickering... Any other ideas?

First, there appears to be a mistake in the file. The orient attribute is a 1-float wheras it should be a 3-float or a vector (?).

Second, slightly increase the spec and reflect angles in the shader and/or increase sample in the mantra properties and possibly add motionblur. Perhaps smooth the orient attribute.

Does it still create flickers if you do that?

[Macha]

Err...Play with the dicing parameters in the mantra node. Perhaps Bias Along Normal. In the past altering those settings has helped me solve some wire display problems.

Or slightly timeblend some frames in post.

Tinsel, glitter, Christmas, perhaps a bit of flicker is a good and festive thing?

Edited December 1, 2010 by Macha