Refraction surface offset shader option?

[Metzger]

I was wondering if there is a way to correctly calculate glass thickness with a single wall mesh. Like if I had car windows, but I didn't model thickness. So there might be a refraction option to do an offset at render that can correctly calculate any thickness. So a value of 1 would be 1 centimeter.

Sometimes dealing with automotive CAD data can be a huge pain if they export car models without merging vertices. Manipulating CAD data under windows in Maya 2011 is a non funny joke. The way it handles memory is very poor compared to Maya 2011 under Linux.

Just wishful thinking.... Although, I think fur clumping and more GPU support should definitely come before that. :P

[Buck]

I 2nd this suggestion, quite often models are not modeled with thickness for glass objects, it would be quite handy to be able to still get good refraction through them with an option for that in the shader, even though they are single sided. Is this something that would be difficult or time consuming to do? Would be nice to eventually see this, the issue of glass not having thickness in models comes up quite often.

[Morbid Angel]

if you set refraction to 1.0 this will be equivalent to no refraction, i.e. no bending of rays, this can do the trick?

[Buck]

but then there is no refraction.

[snivlem]

Do it as a decimal point then! Also Maya's new thickness attribute is aweosme. Saves heaps of time and probably your best option.

[kweechy]

Not sure how the decimal point would help out. The idea is to get a thin walled surface to refract as though it had nominal thickness. Currently, it acts as though it had infinite thickness. Setting thin faced windows on a car to 1.52 refractive index will give you a render as though the entire interior of the car is encased in liquid glass.

Only option is to extrude out your windows, which isn't always a great option either if dealing with CAD data, trying to keep poly counts down or trying to keep modeling hours down.

[snivlem]

Not sure how the decimal point would help out. The idea is to get a thin walled surface to refract as though it had nominal thickness. Currently, it acts as though it had infinite thickness.

Well, I thought instead of 1.6 for a thickly modelled glass, perhaps something like 1.006 or similar would be equivalent? But i haven't bothered working something like this out and what I should be using.

Only option is to extrude out your windows, which isn't always a great option either if dealing with CAD data, trying to keep poly counts down or trying to keep modeling hours down.

Yeah, in Maya 2012 there is a thickness attribute FWIW. Works fast you could just select all windows extrude and enter in a thickness which will go across all windows instantly.