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One of these days I'm going to sit down and see if I can reproduce this kind of material with Maxwell.

http://en.wikipedia.org/wiki/Retroreflector

any suggestions?

...you got me thinking the same thing when i read your thread in the other section... I shall try & give it a go this week. Have a few bits of reference at work i can use.

I'm interested.



....hey Sampson.

This seems more of a modeling task than making the right material.

so Mihai, ....then your saying, if modeled correctly, then it should work?

sort of....I'm saying it should work, if modeled correctly.

Sure... all you have to do is model a trillion tiny glass spheres......

maybe some sort of particle distribution over a surface…hmmm

I did a test tonight of a textured coating (two layers: one BSDF, the other just a coating with a weight map) it wasn't exactly what I was going for (although it seems as though this might work for the new type of traffic signs).

I'll do more tests and post some images later this week.

michaelplogue,

Man, if your too lazy to do it... I'LL DO IT. shouldn't take too long in lightwave... just make a tiny 8 polygon sphere and open up the clone tool, type 1,000,000,000,000 copies, click OK... hmmmm.... what the... some sort of delay...

funny... the hourglass is still there... what gives?

I wonder if maxwell will crash with 8 trillion polygons?

;P

ian.

I'm not sat with a copy of Maxwell so I can't test these, but I've knocked up examples of the reflectors shown in the wiki.

http://rapidshare.de/files/22412304/Ret ... s.rar.html

RAR compressed file containing .OBJ .DXF .LWO & .3DS (3ds might not work.) These were modeled with Blender & I've always had issues importing Blender meshes straight into studio (missing faces & the annoying tri issue), so use the plug-in for your 3D application to send them to studio.

A set of 3 different retro reflectors in mesh format. Duplicate each mesh as needed.



90' reflectors. (160 1/2 cubes in a flat square formation - 640 faces.)

Spherical reflectors which need to have 2x refractive index of the medium from which the radiation is incident. (224 spheres in a flat square formation - 14336 faces.)

1/2 spherical mirrors. (224 1/2 spheres in a flat square formation - 7168 faces.)

As far as materials, either chrome or similar for the 90' or the 1/2 sphere versions and glass with exactly 2x ND of air.

I'll run some tests with these when I get back to my copy of Maxwell.

Hope they are useful and most of all work.

Tim.

wow, thanks!

downloading now and will run a test tonight/tomorrow.

The trick for retroreflection is to have a complete sphere halfway embeded in some opaque material. This way, no matter what angle a beam of light hits it, it will refract , reflect, and refract once again - exiting the bead at exactly the oposite direction it initially entered.

Here's an example on how it's used on street lines.



So Ian - after you generate your trillion spheres, you'll need to duplicate them, boolian the duplicates from a thin box, then bring back your original trillion spheres with a glass shader. Should work fine then....

edit (normal maps aint working)

This should actually be easy enough to test using a single sphere 'embeded' in a box. Place a light source directly behind the camera and let'er rip.