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madno
05-20-2012, 02:44 AM
Trying to make a brushed metal surface:

- learned to set up a (simple) energy conserving material (thanks to the forum posts and google).

- learned that reflection depends on angle of incidence. Made a gradient accordingly (values are from a sientific site about alumine surfaces)

BUT:
In many posts and surface node examples I see a fresnel node used. Read about it and always got the message that it decribes the bending of light when it travels though a transparent material. In the examples on the other hand it often is used for surfaces that are not transparent.

Can somebody help me understand this?

XswampyX
05-20-2012, 03:22 AM
http://forums.newtek.com/attachment.php?attachmentid=104476&stc=1&d=1337505570

Fresnel and gradient both look very similar. I would imagine that the fresnel node renders faster, but you have greater control with the gradient node.

Possibly use fresnel 1st and then if you have to tweak the surface go over to using the gradient node.

SplineGod
05-20-2012, 06:49 AM
I tend to use gradients to get the same effect and for the reason you mentioned...easier to control :) Also it allows you to get what looks good as opposed to what looks correct scientifically.

probiner
05-20-2012, 06:54 AM
If you want a Curve + Control go nuts with the Curve node :D

It's what I use the most these days to control the "Level" of things like this, since I don't only control the 'in' and 'out' as I can also control the between a lot.

Cheers

Lightwolf
05-20-2012, 09:05 AM
You can also use Schlick's Approximation from the latest db&w Tools (which also gives you the inverse for diffuse channels).
A little more control than a proper fresnel but also a lot less than a gradient.

Cheers,
Mike

madno
05-21-2012, 02:43 AM
Thanks for the clarification.