[Bf-committers] ior

[Ivan Sedo]

Hi Ton,
have you checked possible issues with that yet?

Ivan

On Sun, 2005-04-03 at 15:52 +0200, Ton Roosendaal wrote:
> Hi,
> 
> The camera is in 'void', so when it sends rays the first material hit  
> will be an IOR > 1.0. For every subsequent hit the IOR value is 1/ior  
> flipped.
> 
> For underwater render, have possibility to start with 1/ior flipped  
> could be useful yah. Will check on the problems that come with that! :)
> 
> -Ton-
> 
> On 3 Apr, 2005, at 15:26, Frédéric van der Essen wrote:
> 
> > Ooops...
> > replace "negative" by "<=1" and "positive" by ">=1" in my post and it  
> > should be correct...
> > Physically, Ior ranges ]0,->[
> >
> >
> >> indeed it is not negative, if one ior was i_1 than for the opposite
> >> direction the ior is i_2 = 1/i_1
> >>
> >> it comes out from senll's law
> >>
> >>
> >> Anyway
> >> On Sun, 2005-04-03 at 12:56 +0200, Frédéric van der Essen wrote:
> >>
> >>> Of course it can !
> >>> the ior isn't lightspeed_in_void / Lightspeed_in_material !!!
> >>> this is the special case of an object standing in void.
> >>>
> >>> the real formula = lightspeed_in_first_material /  
> >>> Lightspeed_in_second_material.
> >>>
> >>> if the light goes slower in the first than in the second, then the  
> >>> ior is smaller than one.
> >>>
> >>> in the case of a bubble in water, the lightspeed is slower in the  
> >>> water than in the air, so the ior is negative when the light
> >>> enters the bubble, and positive when the light goes out the bubble.
> >>>
> >>>
> >>> Daniel Barbeau wrote:
> >>>
> >>>
> >>>> ior_of_material  = Lightspeed_in_void /  Lightspeed_in_material
> >>>>
> >>>> Lightspeed_in_void is light's maximum speed. 300 000 km/sec If i  
> >>>> recall well.
> >>>>
> >>>> Lightspeed_in_material can't be higher than Lightspeed_in_void, so  
> >>>> ior_of_material can't be lower than 1.
> >>>>
> >>>> I guess this could be an Elysiun question and an Elysiun answer.
> >>>>
> >>>> Dani
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> ------------------------------------------------------------------------ 
> --
> Ton Roosendaal  Blender Foundation ton at blender.org  
> http://www.blender.org
> 
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