Diamond ring

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tobak30
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Diamond ring

Post by tobak30 » Fri Jun 13, 2008 9:43 pm

Need a good diamond material for this ring here. And what is the .nk material for white gold?

And how to get the entire ring in focus. The ring is in fact scaled down to 0.017 blender units. Which after my calculations should be 1,7 centimetre.

Thanks for all replies.
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Ring.jpg
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SmartDen
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Post by SmartDen » Fri Jun 13, 2008 10:10 pm

just add couchy_b_coeff 0.03941 or something alike. search the forum
Check normals, dude!

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ViennaLinux
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Post by ViennaLinux » Sat Jun 14, 2008 12:27 am

and for the sharpness .. do NOT open the camera lense that wide....

so set the F stop value to something high .. to be on the save side take 32.
tell me if that solved it ;-)
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zsouthboy
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Post by zsouthboy » Sat Jun 14, 2008 11:39 am

Ah yes, the macro shot.

In real life, we photogs have to use an insane aperture value to get any DOF at all - something like f/32 to f/64.

Try that and see what you get.

EDIT: oh and should've mentioned - there's no .nk for white gold. Try using the Specular Reflectivity setting with a light yellow as your base color?

tobak30
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Post by tobak30 » Sat Jun 14, 2008 7:03 pm

I rendered this piece with an f/64. Does it help to resize the camera or something like that?

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Kram1032
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Post by Kram1032 » Sat Jun 14, 2008 11:31 pm

O.o how big (or small) is that ring?

The cam is a dot, so to say... A dot which shoots rays in all the directions, where you see something on your screen.

An other way to reduce DoF is to use a more zoomed lens, I think...
(So, but your camera further away but adjust the filmsize in order to get the same effect...)
- though, this causes things to look flat ;)

tobak30
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Post by tobak30 » Sat Jun 14, 2008 11:38 pm

hmm. okay. I mentioned how big the ring is in hte first picture. Its diameter is 1.7 cm.

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Kram1032
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Post by Kram1032 » Sat Jun 14, 2008 11:42 pm

oh sorry^^

The inner or the outer diameter?
If it still doesn't work, you might want to scale it up (although that's just if you get impatient with getting it sharp, as it simply would be wrong^^)

tobak30
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Post by tobak30 » Sun Jun 15, 2008 12:10 am

its the outer diameter of the ring.

What filmsize would i have? I got the 35 mm film in blendigo. Shoul i set it to a higher value?

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Kram1032
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Post by Kram1032 » Sun Jun 15, 2008 12:17 am

I think higher, yes... Though, you need to adjust the camera in blender. Setting it higher means zooming in...
There also is a setting inside blender...

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zsouthboy
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Post by zsouthboy » Sun Jun 15, 2008 2:22 am

No no no Kram :P

Both higher focal length and wider film DECREASE apparent DoF.

tobak:

If you're okay with it, I'd love to take a look at the blender scene - f/64 can end up being less than a few cm of DoF if you are focused a few cm from the "lens"

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Kram1032
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Post by Kram1032 » Sun Jun 15, 2008 4:59 am

ok, then do the other way round... xD (in that case, your render gets pretty distorted, though)

tobak30
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Post by tobak30 » Thu Jun 19, 2008 7:37 pm

Here is the file for your enjoyment. i have changed some things there as there are a closed cube now and 2 mesh lights.
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ring.blend.zip
Here you go.
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zsouthboy
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Post by zsouthboy » Fri Jun 20, 2008 2:31 am

Thanks tobak, I'll take a look.

EDIT: WHOA

That's quite small!

It's a pain working at such small sizes - here's a tip: create your scenes at 10x real scale (so that it's easier to work with), then use the "Scene Scale" adjustment in Blendigo to reduce it on export! So much easier than dealing with blender and very small units :)

EDIT2: Real diamond has an IOR of 2.417ish - i'm looking up the cauchy or sellmier measurement now

EDIT3:
Couldn't find a cauchy number anywhere, but .04 as you had it looks good.
To fix your focus, I changed the focal length to 125mm and instead moved the camera slightly closer to compensate, then changed the film width to 22mm.

EDIT4: Well that improves the situation, but does not fix it. I'm going to just change the aperture size directly, because f/64 isn't high enough for this particular scene.

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zsouthboy
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Post by zsouthboy » Fri Jun 20, 2008 4:09 am

Okay, here is the changed blend.

Changes from yours:
Scene scaled by 10x.
The modifiers you had on the ring caused holes in the mesh to appear (edgesplit then subsurf) - I approximated what you intended with bevel then subsurf then edgesplit.
Ground plane moved up to make ring "rest" on it.
Camera focal length changed to 125mm.
Camera moved closer to compensate.
IOR for diamond changed to 2.417
Scene scale setting in blendigo set to .1x

Upon export:
go into default.igs and add four zeroes after the decimal point for "aperture width"
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im1213889960.png
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