CGTalk - Reflecting Hair

Frubes

04-02-2006, 05:33 PM

Hi guys

I have had some minor success reflecting hair. Unfortunately whenever i try to apply the same technique used below to my scene using exactly the same settings i am getting rather large memory errors. I have 2gb of memory and a 3ghz cpu its asking for mammoth amounts to complete the render.

Can anyone suggest a setting which could reduce the amount of memory used????? The scene consists of e-light (yes yes yes i know thats lots of lights) a ground plane a mirror and a sign oh and my character with the hair on , using textures rather than shaders and the max standard mirror material. Within the scene below i used just a standard 3 point lighting setup.

If anyone has any ideas on how i could overcome these rendering blips i would be grateful. Even if it involves seperate renders or compositing.

http://img375.imageshack.us/img375/3472/shot17xk.jpg (http://imageshack.us)

Mauritius

04-04-2006, 12:51 AM

Use a reflection map.

.mm

tweeeker

04-04-2006, 06:37 AM

Raytracing and hair don't really get along too well, the problem being memory requirements as you've found. Even if you do have the memory you'd prbably find it's horribly slow. So, most people use deep shadowmaps for shadows and reflection/environment maps for reflections. Your fur ball reflection would be much better done as a flat mirror for example.

T

Frubes

04-04-2006, 11:38 AM

Thanks for the replys guys, tweeker do you know of any tutorials on creating this type of relflection. I have never really used this type of material creation method before and the notes in the help files are fairly small. Any more info on this would be really handy.

Many thanks

Mark

lazzhar

04-06-2006, 10:56 AM

I think guys are refering to creating a reflection map by rendering twice( or more). Let's say you want your object is to be reflected on a flat mirror,; Instead of just enabling the raytraced reflections you would go creating a new camera and put it in the oppoiste side of the mirror to get exactly what the mirror is "seeing" from that point of view. Then you can apply the rendering picture as a reflection map on the mirror. I know there is an automated solution making this coming with Renderman Artisit Tools but I have no idea about other.. in fact I was looking for something like that if someone could help.
Yes sometimes the results couldn't be accurate, but as it looks nice and plausibe, who cares?! Especially when you remember that people in live action shooting always cheat in "Real Reflection" to get better pictures and avoid seeing the camera reflected somewhere on the screen.

Frubes

04-06-2006, 01:48 PM

thanks lazzhar thats exactly the solution that i am going to employ now. The only way i know how to go about it is to render the mirror pov shot and then the primary camera shot with the texture applied to the mirror. That works and yes its a little innaccurate if the camera for the mirror is set up incorrectly but hey no one notices that much eh :P Thanks for the help guys.

Mark

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