rendering hair ..

[farhaad_yousefi]

hi
i have a dandelion build up..and it's with the hair system
but all the hairs that turns into the camera ..go invisible..on close shots
how can i fix this problem, i mean the hair thickness doesn't seem to solve it either..looks like the hairs are paper bars..!!

[Hirazi Blue]

From this thread on the Mailing List - which talks of strand-based hair, but for rendering purposes there shouldn't be any difference - I gather that it might help to switch from the "Hair Shader" to the "Hair Gradient Shader" (the old "Hair Geo Shader")

Quoting Alan Fregtman from the aforementioned thread:

The default hair shader (if I'm not mistaken) draws shaded lines. The
alternate factory one I remember would render tubes of geometry --
kinda looked like tubes with a default phong.

;)

[sant0s]

did you any brush action to the hair? becouse if not, i think its normal that there is some kinda "skinhead". the hair grows away to the objects normal - so if you have a sphere, there will be always a part, where you can see through

so maybe your hair does not disapear, you only see the tiny tip of some hairs? just an idea.

[Mathaeus]

From this thread on the Mailing List - which talks of strand-based hair, but for rendering purposes there shouldn't be any difference - I gather that it might help to switch from the "Hair Shader" to the "Hair Gradient Shader" (the old "Hair Geo Shader")

Quoting Alan Fregtman from the aforementioned thread:

The default hair shader (if I'm not mistaken) draws shaded lines. The
alternate factory one I remember would render tubes of geometry --
kinda looked like tubes with a default phong.

;)

a bit of nit-picking (dr. Freud would have to say something about me, here), but I think this isn't true. I'd believe both of them draws a "flat" line, but hair "geo shader" simulates a tube-like shading, still on flat line, similar to shading method of old particles. Old names are probably a heritage from times of xsi 4 or earlier (exactly from my knowledge, XSI 3 EXP), when "hair renderer" used volume shading, geo shader meant no-volume.
I'd try something along sant0s's advice.

[farhaad_yousefi]

i've solved the problem using 3delight,it's awesome on hairs.and fast..
but still curious about this solution..

[Mathaeus]

i've solved the problem using 3delight,it's awesome on hairs.and fast..
but still curious about this solution..

3delight out-of-the-box is also 'flat line', For tubes, I think the only way is to go with some mesh extrusion along strands.
On the same mailing list, there is a post with something tube-like, post is about carpets. Rendered in Arnold. Are these tubes 'real', I don't know, of course.

[Hirazi Blue]

a bit of nit-picking (dr. Freud would have to say something about me, here), but I think this isn't true. I'd believe both of them draws a "flat" line, but hair "geo shader" simulates a tube-like shading, still on flat line, similar to shading method of old particles. Old names are probably a heritage from times of xsi 4 or earlier (exactly from my knowledge, XSI 3 EXP), when "hair renderer" used volume shading, geo shader meant no-volume.

@Mathaeus - You're probably right, I was merely quoting from that thread, not speaking from direct experience, assuming that the fact the thread ended quite abruptly shortly after that and there was no outcry of the "no you're wrong" kind, that there might be something to it.
;)

edit: how about hair instancing?

[farhaad_yousefi]

you're right.. still hiding the hairs when pointing to the camera..though the bad shadowing is gone..but ..i can't seem to get any shadow..maybe because of the shadow map.!?!?

[sant0s]

can you post an image?

with dandelion you mean this flower where you can blow away the seems, right?

maybe you should try hirazis tip with instances.

create one seem like on this picture: http://img.fotocommunity.com/photos/12928810.jpg and use as instance.

[Hirazi Blue]

You could try playing with the "Render Settings > Shading Model"
and more specifically with the "Normal Blend" (read all about here)
;)