Welcome to TINA CHeP :: View topic

ThomdeG · Joined: 04 Nov 2008 Posts: 334 Location: NL

ThomdeG wrote:

3DSteve wrote:

texture{
Chrome_Metal scale 1.0
normal{ bumps .1 scale .00000001}
finish{ reflection .015 phong_size 20 phong .05 ambient 0.35}
}

Note that for this to work it has to have a fairly high ambient so adjust as necessary, I used 0.35.

What about adding this"to the finish:
irid {
0.2
thickness 0.6
turbulence 1
}

Looks *realistic*... Cool

I took up again Steve's texture, added the irid, rendered with radiosity, set ambient to 0.

Only registered users can see links on this forum!
Register or Login on forum!

[/img]

_________________
All the best,

Thomas

"Sic vive, tanquam cras moriturus, sic stude, quasi semper victurus." Desiderius Erasmus

clipka · Joined: 04 Nov 2008 Posts: 254

ThomdeG wrote:

I took up again Steve's texture, added the irid, rendered with radiosity, set ambient to 0.

Doesn't look like a pearl to me at all, to be honest.

It recently seemed to me that a key ingredient for a realistic pearl is high - but blurred - reflectivity.

In any case that means it needs a good environment to reflect, probably a HDR background. POV's classic fake specular highlights won't do.

ThomdeG · Joined: 04 Nov 2008 Posts: 334 Location: NL

clipka wrote:

Doesn't look like a pearl to me at all, to be honest..

I agree that it looks anything but. However, I was just trying to think about something that seemed to be missing from the code, the iridiscence, mother-of-pearl sheen. Confession: I am not a pearl expert Smile

clipka wrote:

It recently seemed to me that a key ingredient for a realistic pearl is high - but blurred - reflectivity..

Hmm, yes, especially blurred I think. I'll give it a try.

clipka wrote:

In any case that means it needs a good environment to reflect, probably a HDR background. POV's classic fake specular highlights won't do.

Agreed.

_________________
All the best,

Thomas

"Sic vive, tanquam cras moriturus, sic stude, quasi semper victurus." Desiderius Erasmus

DrNo · Joined: 03 Jan 2009 Posts: 395

clipka wrote:

Doesn't look like a pearl to me at all, to be honest.

I agree. It looks like silver-like metal.

clipka wrote:

It recently seemed to me that a key ingredient for a realistic pearl is high - but blurred - reflectivity.

I think the key ingredient is subsurface scattering. The fuzzy reflection is due to pearl translucence, not surface roughness.

Using blurry environment mapping is likely to produce metal-like shading, because that is exactly what one would do to render a chrome sphere.

I made another pearl test using the same setup. Difficult to be fully convinced without any reflection, but maybe we still feel it somehow.

Only registered users can see links on this forum!
Register or Login on forum!

_________________
DrNo

rmcgregor · Joined: 15 Apr 2009 Posts: 63 Location: Central Florida

Wow, better late than never I guess - I've been reading through various threads and just found this one - here's a simple pearl texture I came up with a few years back:

Code:

texture {
pigment {color rgb 0.85 }
normal { bumps 0.025 turbulence 0.5 scale 0.05 }
finish {
irid {
0.35
thickness 0.35
turbulence 0.35
}
specular 1.0 roughness 0.02
reflection { 0.15, 0.25 fresnel on} conserve_energy
}
}

Example render w/focal blur (also from a few years back):

Micronormals and SSS would certainly help.

Cheers,
Rob

ThomdeG · Joined: 04 Nov 2008 Posts: 334 Location: NL

rmcgregor wrote:

Wow, better late than never I guess - I've been reading through various threads and just found this one - here's a simple pearl texture I came up with a few years back:

To me, this looks good.

_________________
All the best,

Thomas

"Sic vive, tanquam cras moriturus, sic stude, quasi semper victurus." Desiderius Erasmus

clipka · Joined: 04 Nov 2008 Posts: 254

rmcgregor wrote:

Wow, better late than never I guess - I've been reading through various threads and just found this one - here's a simple pearl texture I came up with a few years back:

While this does look good indeed, be aware that POV-Ray's "irid" mechanism is exceptionally ill-behaved, and may fail spectacularly under certain (not too uncommon) illumination conditions.