View Full Version : Accurate Index of Refraction

11 November 2009, 08:42 AM
Hi all,
I have a question about index of refraction.

I have a scene with some water bottles that are supposed to be full of water.
The refractive index of water is 1.33, but the refractive index of the bottle itself (PET material) is 1.57.

Due to the heaviness of the scene I do not want to model and render the inside of the bottles as a separate object.
So using only one object and one refractive index, what refractive index would be closer to reality in this case?

I'm using mia_material btw.

11 November 2009, 02:45 PM
Can't you give the bottle shader a RI of 1.57 and the water shader a RI of 1.33?

11 November 2009, 03:43 PM
I have only one object (I don't have a different model for the "water" part) thus only one shader...

11 November 2009, 05:02 PM
You'll need to model the liquid seperate from the bottle to get realistic IOR.

11 November 2009, 04:33 PM
You'll also want to model the interior of the bottle. Even a plastic bottle doesn't have infinite thin-ness. Glass is generally thicker. Might be more work, but if you want them to look "realistic", that's what you would do.

The bottle should be one curve, inside and out, revolved, converted to polys.

Alternatively, if you're insistent on using only one mesh, you could texture the bottle to have the appearance of liquid inside it.

11 November 2009, 06:02 PM
you'll need to think of the dielectric interface too if you're going for absolute accuracy.

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