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gem stones

Dreamer

Dream Weaver Designs
Contributing Artist
Hi there, I am trying my best to get a shader together that looks like amethyst and so far am not having much luck.
I started with a shader BagginsBill had posted over on RDNA and while it works mostly for what I want its not quite there on things that are a bit see through
PinkStone.jpg
Horn.jpg
Any one got any ideas?
 
Have you tried SnarlyGribbly's EZMat freebie - it includes various gemstone shaders. I think it's hosted over at CGbytes now?
 

Gadget Girl

Extraordinary
Contributing Artist
I'm not great with shader's, but my first guess might be to try adjusting the Transparency Falloff.
 

Dreamer

Dream Weaver Designs
Contributing Artist
Have you tried SnarlyGribbly's EZMat freebie - it includes various gemstone shaders. I think it's hosted over at CGbytes now?
Nope I hadn't tried that, I might even have it lol. Will go have a look.
I'm not great with shader's, but my first guess might be to try adjusting the Transparency Falloff.
I didn't think of that ether, its a setting I don't play with much
 

Dreamer

Dream Weaver Designs
Contributing Artist
Well I tried EZMat and while its very cool and I can see using it for lots of things it didnt quite work out, how ever I had another go at tweeking a shader to fit my needs and have got some thing that works. Thanks for the the tips guys ;)
 
I think bagginsbill usually, unless I'm much mistaken, recommends not using transparency at all as it's completely fake. Real world transparent objects are 'transparent' because of refraction, and appropriate* adjustments of the 'Refract/Reflect/Fresnel Blend' part of the shader in the OP should be all you need.

You might try increasing the Index_of_Refraction to 1.5 or 1.6 (according to this 2007 post Diamonds That Look Like Diamonds in Poser 6 - How? ) in both the Refract and Fresnel_Blend nodes, see what happens. The rest of the stuff on that thread is probably rather outdated now !

Having said that, renders are all about what the final image looks like, and if tweaking transparency gives you a more pleasing result (as it sometimes does) all's well and good! :D


*Knowing what to adjust is the key, and you really need to track down threads where he explains the Refract/Reflect/Fresnel Blend setup*. Page 2 of the "SSS Eyes best Technique" at RDNA is a very interesting read (and just to contradict what I said, he uses transparency too! Well, it's not really a contradiction - he applies it to a 'faked' material, so that's okay!) If you read through his posts on that page a few times you should reach that Eureka! moment.
 

Dreamer

Dream Weaver Designs
Contributing Artist
I think bagginsbill usually, unless I'm much mistaken, recommends not using transparency at all as it's completely fake. Real world transparent objects are 'transparent' because of refraction, and appropriate* adjustments of the 'Refract/Reflect/Fresnel Blend' part of the shader in the OP should be all you need.

You might try increasing the Index_of_Refraction to 1.5 or 1.6 (according to this 2007 post Diamonds That Look Like Diamonds in Poser 6 - How? ) in both the Refract and Fresnel_Blend nodes, see what happens. The rest of the stuff on that thread is probably rather outdated now !

Having said that, renders are all about what the final image looks like, and if tweaking transparency gives you a more pleasing result (as it sometimes does) all's well and good! :D


*Knowing what to adjust is the key, and you really need to track down threads where he explains the Refract/Reflect/Fresnel Blend setup*. Page 2 of the "SSS Eyes best Technique" at RDNA is a very interesting read (and just to contradict what I said, he uses transparency too! Well, it's not really a contradiction - he applies it to a 'faked' material, so that's okay!) If you read through his posts on that page a few times you should reach that Eureka! moment.
Ah I didn't know that about the transparency, will have to have a play with it at some point. I ended up using BB's jade shader and tweeking till it looked close to one of the bits of amethyst I have ;)
 
I've found the specific quote I was thinking of - it's the next to last post on page 6 of the Renderosity "Underwater Submarine" thread.

"...you're still using transparency in your water plane, and adding a very blue diffuse reflection. Neither of those things should be happening. The light color now shifts to blue and you don't need to fake it in the water plane. Use refraction and reflection, modulated by a Fresnel_Blend node."

While that quote was specific to water, I think it applies to other stuff too.

And of course, the right solution for any picture is whatever works for the creator ! Nice to hear that you sorted it out :D
 
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AllenArt

Enthusiast
Try this. I don't have Poser installed atm (installing Windows 10 on all my machines and in various stages of doing so ;)). This shader is completely clear and uses no transparency. It's for Firefly. Remove the .txt extension before you use it...heh. You can also make it any color by changing the color chip that sets the color.

IIRC, I made this shader in Poser 9/Pro 2012

Laurie

Violet.png
 

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