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View Full Version : How to make edges glow?



medicalart
04-22-2008, 07:36 AM
I frequently see biological images with bright edges instead of shadows on the subject. (See sample that I grabbed from a website). Any ideas how to do this in LW? Thanks.

PS. In Photoshop, I would just invert the colors.

Lightwolf
04-22-2008, 08:01 AM
Add a gradient on the luminosity of your surface that depends on the incidence angle.
That ought to get you started.

Cheers,
Mike

medicalart
04-22-2008, 08:21 AM
I'll give it a try. Thanks.

tvtom
04-22-2008, 04:06 PM
You could try fast fresnel on the diffuse with a high glancing angle. Crank it way up to like 400%.

That will be in the "Shaders" tab of your Surface Editor.

Oh, and that's affected directly by lights so move your lights or add lights to get what you want.

tvtom
04-23-2008, 07:55 PM
I did this real quick on my laptop to see... That incident angle gradient is in the other channels there also (just black and white). I got to playing there so there's a little bump action with the incident angle as an alpha. :p

Oh, and turn off shads.

medicalart
04-24-2008, 07:10 AM
TvTom: That looks good. I will experiment with it. Thanks for posting.

starbase1
04-28-2008, 08:59 AM
An incidence basd gradient is my favourite kind, very useful! Also handy for making things reflective at shallow angles only, which is the way the real world tends to work...