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This is a bit of a strange one...

This render has gotten to SL 14.58 on my unbelievably crap workstation after about 20 hours or so at 1600 x 1600 pix.

Anyway - i'm reasonably happy with how the main yellow diamond has come out, but the small (páve) diamonds, look a bit cack. The dispersion in them is just kinda poor. The model is fine I think, and the lighting has worked for the main stone.

Is it simply a matter of allowing it to cook for longer to work out more reflections?

I often find this a problem with the smaller stones, but not the larger ones. Is the answer simply to scale the whole shebang up maybe?

Advice appreciated.

Not sure about you but i think it looks clean and good the way it looks now, and pretty realistic with dispersion and such on the gems. Maybe the smaller stones look could be improved by modeling in a small cavity (read hole) below each stone so that light can be let through the stone and ring, now it stops into the metal and just bounces around inside there ending up all greyish colortinted by the metal ring.

Much like this ring has holes that runs through the entire ring so that light can pass through the gemstones more freely.

http://www.ganoksin.com/borisat/nenam/n ... PJM-02.jpg

/ Max

Nah - there are already holes that go through into the body of the ring. - i wouldnt just have them dead backed, as obviiously it has a detrimental effect on a stones brilliance.

I know I'm being fairly picky about this but, hey, we're all here to improve!

From my experience

a)You must make sure metal is not crossing stones, that usually kills them play safe, leave some room between the stone and the settings, and cut the prongs. Using the stones a bit smaller helps.

b)Lightining is important, you need contrasting light all around the part. The transition between light and shade is where the dispersion comes up. You could either spread some point lights or use HDRI environments, what I preffer.

c)Render a material id image and pump up the paves in photoshop, using it as a masking guide.

Ricardo

thanks for the tips ricardo, however:

a) the metal on the pegs needs to overlap the stones, as it would be a worse error to not show it being as correct as possible from a modelling standpoint.

b) I'm already using HDRI for reflection, refraction etc, but not illumination. My illumination channel is disabled and the scene is illuminated by a U shaped hood with white light at R242 G242 B242.

c) I dont know about material id image so I will look into that, but I'm not sure how that will help with the stones refacting properly.

Perhaps, even though there are cavities behind the stones, they are just touching the main ring, thereby killing them. I'll do a test with small stones more open and see what happens.

Maybe the real problem is that you're way to super picky about your work, to be completly honest the small gems does not look that bad. I do think they look realistic and they're contrasty and 'colorful' like they should be.

/ Max

Jakakadave wrote:thanks for the tips ricardo, however:

a) the metal on the pegs needs to overlap the stones, as it would be a worse error to not show it being as correct as possible from a modelling standpoint.

Perhaps, even though there are cavities behind the stones, they are just touching the main ring, thereby killing them. I'll do a test with small stones more open and see what happens.

What I meant is the mesh from the stone is crossing the mesh from the metal, that's not good. You need to fake a gap between them.

I think the guys are right when they say that the diamonds are meeting the metal- I am a goldsmith and understand what you are saying about the metal having to be over the stones but.... if you have any metal intersecting with the stones they look grey and dull.

Here is what I do in Rhino:

I often will copy my gems in place and then hide one version.

I then will do a Boolean difference to remove the gems from the ring- this will essentially cut seats for your diamonds without you having to do things to your physical model that you would leave for doing in the actual metal.

Then I just bring out the diamonds that were hidden and then render.

Voila no more grey diamonds.

Hope that helps I now need to go and figure out HDR images!
Cary

ricardo wrote: What I meant is the mesh from the stone is crossing the mesh from the metal, that's not good. You need to fake a gap between them.

Ah I see what you mean - I think Cary is right, a boolean is the answer, then no crossing meshes which means that there will be no metal actually INSIDE the diamonds, as there currently is, disrupting it's refraction and throwing the light bounces off.

Your ring looks so good I have a couple of questions, if you feel comfortable answering.

What HDRI did you use in your background? It really looks to make a positive difference.

Also how did you make the yellow diamond material? Complex IOR or did you use an MXM file? Any tips from you would be great. Thanks
Cary

Ya, you need to make sure NO METAL is intersecting with any diamonds in the pavillion area. The prongs are not as much of a concern if they are intersecting that diamond in the table area.

Also, you could try intruducing another light panel below the camera to help light up those smaller diamonds if you are still getting dull diamonds.

Ricardo's tips are all good too. Softbox light panels are a must in combination with small strong lights for dispersion.

This is a dosch map i like for diamonds

Ricardo when you say that "this is a dosch map i like for diamonds" are you using that image as an HDRI for reflections? If so could you point me in the direction where you got/purchased it? Thanks
Cary

That map might work well with diamonds, but what about reflection on gold? I think you'd get a lot of busy reflections on round profiled rings.

caryjames wrote:Ricardo when you say that "this is a dosch map i like for diamonds" are you using that image as an HDRI for reflections? If so could you point me in the direction where you got/purchased it? Thanks
Cary

It is part of a studio environments from dosh http://www.doschdesign.com/products/hdr ... ts_V2.html, mine is the old V1.

Blitzor you are right, it's not aways the best choice for polished metal, works fine on brushed/sanded.

Ricardo