View Full Version : plastic or glass?

05-14-2010, 05:47 AM
Hi all:)
New question. Why plastic looks like plastic and glass like glass? What makes the difference?
I have to prepare the plastic bottle, which in the previous version was a glass.
Maybe somewhere are settings for glass and plastic? Anybody know anything about this?

05-15-2010, 05:29 AM
well..plastic comes in quite a large range of different transparents and thickness.

so you really need to verify and state what type of plastic you are going to do.

I think plastic has less transparency and a little of subsurface scattering or translucent material, you could also use refraction blur..to make the light
scatter in the material, itīs similar to frosted glass.


05-15-2010, 10:21 PM
Using the correct IOR - index of refraction can help as well.


05-16-2010, 12:07 AM
A few years ago for a job, I had a couple of pieces of acrylic that were diamond polished. They looked like pieces of crystal glass. The sides were perfectly flat, no imperfections, the clarity & other qualities of the material took on a different level, equalling the best or surpassing that of glass.

But a plastic soft drink bottle looks exactly what it is.

05-16-2010, 05:30 AM
Using the correct IOR - index of refraction can help as well.



05-16-2010, 06:31 AM
I don't think IOR will help you much here, as long as you keep it around 1.4-1.6.
BTW, lots of common materials missing in that list, like Polyester, Epoxy etc.

What will give it a more plastic look in my experience is to use a more bluish color for it, instead of the greenish one commonly used for glass. Glass "always" contain small traces of iron, which will give it a greenish tint when thick, or when viewed at certain angles.
Plastic more often have a bluish (or other color) tint, and it often also have a lot thinner walls than glass. Use Color filter to see the color, or high absorption with Dielectric.
Vacuum formed plastic will also have thinner walls where it has been stretched the most.

05-17-2010, 03:00 AM
hereīs another big table of refraction indexes.
also thereīs some explanation of refraction and light.
It also has an refraction simulator.



05-17-2010, 03:03 AM
some explanation of the polyester material, and some values for the refractions.



05-18-2010, 02:21 AM
Sorry I did not answer, but we had a flood here... Anyway, now it's better so i come back to question:)

And what about smooth threshold and fast freshnel? Should be different setting like in glass? Any experience?

05-25-2010, 10:05 AM
End of topik. I realized, that no matter how it looks really plastic. It is important, as he imagines brand manager. Or, as you can convince him that it looks like:)

Thank you for any hints.