Iridescence

[Elowan]

Is it possible to produce an iridescent texture/effect in LW? :where:

[Gordon Robb]

Remind me, what does irridescence look like?

[BillS]

yep.. got an example?

[Elowan]

From the WIKI: Iridescence is an optical phenomenon in which hue changes with the angle from which a surface is viewed. Iridescence may be easily seen in soap bubbles and butterfly wings.

I'll see what I can come up with. I saw something on the tube about it and was inspired to seek out expert opinion(s).

[Gordon Robb]

Let me know if you find any (experts that is) ;)

[Elowan]

Let me know if you find any (experts that is) ;)


Well ... I had no luck on the Flub-a-dub site so ... :crazy:

[JackN]

Sounds like the optical phenomenon that you get when a drop of Oil hits water.


I used to use interfere.p in the older LW, you can probably just use a rainbow color map and a gradient for incidence angle now days...

[Bells of Freedom]

I know this is possible in LW. I'd say either the Node Editor, or a gradient set to incidence angle, or light incidence angle.
When I think of iridescence I think of translucent, shiny, multicolored insect wings where colors change according to viewing angle.

[Rigel]

There is a car painting technique now that does this; the car changes colours as you walk around it. The first time I saw it (about 10 years ago) it was a 1964 Mustang which was dark purple as I approached it, then dissolved into an incredible metallic green then that melted into a beautiful bronze colour. The owner told me they can do up to 6 colours and the three colour job he had done was $3000.

I'm thinking you want to approach this with gradients in some fashion or another, one layer for each colour. Have very different angles set to each colour so that as the object changes its angle to the light, it shows up a different colour.

But, I've never tried to do something like that so I am just guessing.

[Elowan]

...
When I think of iridescence I think of translucent, shiny, multicolored insect wings where colors change according to viewing angle.

That's the effect I'm referring to. :tu:

[DaveK]

If you are using Lightwave you might try the BRDF shader. Also years and years ago there was a tutorial where you added two or three clear layers. Each layer only reflected red, green, or blue, The top layer was 66% transparent, the second layer was 33% transparent, and the last layer was solid. By offsetting the texture maps, by some slight amount, you got an iridescent finish. I'll see if I can find the tutorial. Hope that helps.

[Elowan]

If you are using Lightwave you might try the BRDF shader. Also years and years ago there was a tutorial where you added two or three clear layers. Each layer only reflected red, green, or blue, The top layer was 66% transparent, the second layer was 33% transparent, and the last layer was solid. By offsetting the texture maps, by some slight amount, you got an iridescent finish. I'll see if I can find the tutorial. Hope that helps.

That does! I'll give 'er a go and thnx! :tu:

[BillS]

hmmm... if you took a couple noise (marble maybe) nodes and upped the contrast quite a bit.
Feed those into the input of an incidence gradient that has 5 or 6 colors in it. Different for the two of them.
Feed the gradients into a mixer set to something like overlay or multiply
Put that into the diffuse or if its there.. trans color. That could give you what your looking for ... I think. I am at work and can't check if it would work right now.

[BillS]

Anything like this?
http://www.foundation3d.com/uploads/instruction/2008/12/8-02-267481_tn.jpg (http://www.foundation3d.com/uploads/instruction/2008/12/8-02-267481.jpg)

If so.. this is what the node setup looks like.
http://www.foundation3d.com/uploads/instruction/2008/12/8-02-267520_tn.jpg (http://www.foundation3d.com/uploads/instruction/2008/12/8-02-267520.jpg)

Here is the preset to play with if you want to try.
Globe Surface.zip (http://www.foundation3d.com/uploads/instruction/2008/12/8-02-267554.zip)

[DaveK]

I'm sorry I can't find the tutorial or who did it. It was way back with LW5.0, which was at least a couple of hard disks ago. I think that Bill has the right idea.

[Elowan]

Thnx for that preset. :tu:

It pretty much is the effect. Can that be used on a 'solid' (non-transparent) surface?

[BillS]

It should work on it. Just kill off the transparency and you will likely have to adjust the gradient in the Diffuse...But that should be it.

[Elowan]

grassy-ass :crazy:

[Josh2481]

I realize this is exaggerated a bit. But this was using a simple incidence angel gradient in the color channel.
18915

[Elowan]

I realize this is exaggerated a bit. But this was using a simple incidence angel gradient in the color channel.
18915


Perfect. What version of LW? I have 7.5d and 9.5 (haven't even started using v9.5 - still stuck in a rut). :crazy:

[Rigel]

I realize this is exaggerated a bit. But this was using a simple incidence angel gradient in the color channel.
18915

I tried to do that in v8.5 and didn't get good results. Mind sharing the settings?

[Josh2481]

I used 9.5 but it was in 7.5 wasn't it?
18976
just used ROY G BIV lol but violet at 0 and red at 90
0, 15, 30, 45, 60, 75, 90
for angles.

[BillS]

Yep it will work in 7.5