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IKEA cup - I need 'dielectric plastik'

Posted: Wed Jul 27, 2005 9:49 am
by sam7
Hi!
I just did some more testing of SSS Meterial. I choose to create this famous IKEA cup. :)
While testing I figured out that I need a material in between dielectric and plastik.

This is my result so far. I like it but it's not exactly what I wanted to achieve.
Image
~10h@lvl13
Plastic settings:
Roughness U,V: 0.2
Absoption: 0.2
Scattering: 0.2


This is a reference Photo I took:
Image


I'm shure I can get better the the result above. But I guess I'll never achive this dielectric/plastik effect.
Do you agree? Or can I do some kind of workaround?

Will there be a combination of dielectric and plastik material in the final version?

Thanks!

Posted: Wed Jul 27, 2005 10:06 am
by Jun In Gi
yes..it would be need more test to get a refrence photo image.

and before you adjust sss, did you reference SSS chart in this forum?

if you answer is 'no', i recommend SSS chart.

Posted: Wed Jul 27, 2005 2:54 pm
by KRZ
i get this effect buy just using a dielectric with some adjusted roughness...

Posted: Wed Jul 27, 2005 2:57 pm
by Hervé
Can I ask something..? (don't kill me ... he he) what is so special about that cup..? :?:

Posted: Wed Jul 27, 2005 3:37 pm
by sam7
@Hervé: It's material ;)

@KRZ: I tried it. But couldn't get settings being satisfactory.
Post some settings and I'l try again :)

For everyone looking for a 'challenge' :D
Here is the vector-file I created the cup with.
Just lathe it: IKEA_cup.ai

- SAM.7

Posted: Wed Jul 27, 2005 3:47 pm
by KRZ
roger that..ill give it a go later tonight

Posted: Wed Jul 27, 2005 9:57 pm
by sam7
Little update:
Image
increased Roughness to 0.9 and set Absoption & Scattering to 0.05

Posted: Thu Jul 28, 2005 6:43 am
by tokiop
Nice tests Sam! It is an interesting situation to test maxwell's SSS, your last results are really geting better, keep on testing!

Cool challenge, I tried with dielectric:
• color: 050 140 147
• Abs: 0,015
• Roughness: 0,8
• SL: 16,?
• Reduced 50 %

Image (hosted by iMaGesHaCk)

Posted: Thu Jul 28, 2005 7:20 am
by Hervé
hmmmm I dont think dielectrics is good for it... nor Plastic... I would do diffuse Mat, and sss set to ab0,8 and scat0... :roll:

Posted: Thu Jul 28, 2005 7:43 am
by Thomas An.
tokiop,

Your result looks very good compared to the photo. Image

Posted: Thu Jul 28, 2005 11:18 am
by sam7
@tokiop

WOW I didn't know I could do this with dielectrics!
Great job!

I'll try it with my scene :)

Thanks!!!

Posted: Thu Jul 28, 2005 3:35 pm
by tokiop
Thomas: Thanks! I think it is easyier to adjust the material.. But you the SSS guru should join the challenge! I find it really hard to adjust SSS, even with your wonderful chart...

Sam: I have no credit for the use of rough dielectrics I just saw this in the past ;) But you might be right, the ideal material should mix dielectrics and SSS (I think Mihai is looking for the same kind of transparent SSS effect for his beautiful flower render).

I tested with SSS:
• color 037 113 108
• Abs 0 Scat 0,8

Image

• color 037 113 108
• Abs 0,8 Scat 0 (for you Hervé, but with plastic - I think we can see some specularity highlights in the reference)

Image

I don't see a big difference between the two SSS tests (they haven't the same burn value and SL.. so it isn't optimal to compare anyway.. :roll:) but the specular highlight and green caustics/reflection on the plane look better than the dielectrics.

I think the lack of specularity on rough dielectrics was pointed out before, but i dont know if it is a bug or a physical-accuracy :D

Posted: Thu Jul 28, 2005 4:31 pm
by sam7
Hi!
I tried it with dielectrics too!
this is my result:
Image
Problem: it's too dark, as you can see, and I don't get nice speculars, as I would get with plastic. (as tokiop already mentioned)

So I faded them both together (50%) in photoshop:
Image
this is not perfect, but get's a little closer :)

Another question is, why the liquid in the cup is soo bright... :?:

Posted: Fri Jul 29, 2005 10:23 pm
by Micha
bright liquid ... the absorbtion of dielectrics is buggy, you can find a post from me in the bug section.