Question about rendering: how to understand IOR?

I’m creating an ocean water texture using texture displacement map. One of the parameters is the IOR setting, which defaults at 1.33. Could someone help me understand what changing this number actually does?


This is index of refraction: how much the element deviated light. Change to 0,0 and there’s no effect, just like vacuum. Set to 2.x and it’s much like diamond.

You mean IOR of 1.0 has no effect.

Correct. 1.0 is ‘nothing’. Wonder what 0 does…?

If 1.0 has no effect, why does the default start at 1.33?

That is the IOR of ‘normal’ water…

I would set default 1.5, it’s good for plastic/wood and needed a lot more often than water.

I was just doing a search for the IOR of ocean water and came across your post.
If you are still confused about the IOR. It is the value given for how much light bends when passing through different materials. The higher the value, the more the light bends. Like how a pool looks shallower then it actually is.

Water is usually the default value on the setting. ie: 1.33 But this is affected by temperature. See table:

  • Water (0 deg C) 1.333
  • Water (100 deg C) 1.318
  • Water (20 deg C) 1.333
  • Water (gas) 1.000
  • Water (35 deg C) 1.325
  • Water Ice 1.310

You can see a wide range of values here:

Sadly my ocean water value is not there but Salt looks like it has an IOR of 1.54. So I could make an inference that if ocean water is ~3.5% salt So 3.5% of 1.54 is 0.0539 as a potential increase in IOR from the salt water in the ocean. Which might give me an IOR of 1.3839 @ 20ºC

Hope this helps :slight_smile: