Reproducing Etched Glass

[jujubee]

Here's a problem:

I've got hundreds of samples of various colored etched glass.


My question:

What's the easiest way to reproduce these patterns in 3D? I need to create bump/displacement maps from them - but when you scan them on a plain scanner, light transmission causes strange patterns rendering it difficult to work with.

Do you all suppose that there is an easier method than having to create them all by hand in photoshop?

[flipside]

Not really sure what you mean, but when I need to scan stuff that is reflective or refractive I usually take a picture of it instead, without flash.

[jujubee]

I need to make bump maps from them - guess camera with flash is one way - any different tricks out there?

[natty]

Can you show an example?

[CCS]

I haven't tried this myself, but it's an idea.

Set a camera on a tripod perpendicular to your glass. Turn flash off. Set up a fairly diffuse light to the right of your glass at a medium-low angle relative to the glass plane. Snap a photo. Now rotate the light 90 or 120 deg and snap another pic. Make sure camera and glass stay stationary. Repeat until you have photos with equally spaced lighting. Merge them together in PS and desaturate. Voila - bump map.

Works in my head - just haven't tried it for real.

[DaForce]

Sweet, found the link i was looking for.

This is kinda what CCS was talking about, and i think its definitly worth a shot.

http://66.70.170.53/Ryan/nrmphoto/nrmphoto.html

[roppin]

or you could color the etched parts with oil paint

[tricky]

I think some of that normal-map stuff was at Siggraph - very cool, but I've forgotten it all

[jujubee]

Hmm some good ideas guys- thanks. Will try to post some results soon.
As for oil - that wont work cause theirs barely perceptible veins in some of these materials - the paint will most likely obscure some of these intentional 'cracks.' But the idea is great if you could manage a finer spray.

I'm trying to some samples for a glass company to possibly post some seamless mats for the general public on their site to download. The've shipped me a whole box of little glass squares. I've asked them if they worked from digital patterns tha tI could borrow but have yet to hear back.

It's just a test to see if a few posted samples makes any difference to their business or drives up traffic. I'm trying to keep total process times down to 15 mins each with template setup and mat creation. It's beginning to look like a tight schedule and may not be economically feasbile. I'm not sure if it's really worth it on their end either....

[jujubee]

I've ordered a photographers light box off of ebay for $19. Should be here in a few days and will run some more tests.

In the meantime, I've built what I've affectionately called a 'Bump Box' with the link Daforce has posted in mind.

Here are some bad pics (hey I was in a hurry) to better describe the problem:

1) Pics of the glass being held to a light.



2) A scan of the glass. You can see it loses significant detail this way. An accurate bump would be impossible with this method.


3) Homemade Bump Box pics. The camera lens snuggles in the top so i dont have to constantly readjust the position. The inside is duct taped with white paper. I decided to stretch out the tshirt after the photo was taken cause it was collapsing the box. You will need:

a. white Tshirt which doesn't fit.
b. plastic box
c. big freakin clippers
d. light source
e. white paper
f. tape

I'm sad cause this box has really outlived its usefulness. I found it in someone's trash and took it home with me. I't been a light box for photographing jewelry, an oil pan for my car, a engine coolant pan for another, and now this...:




Perhaps, I will try to screw with this tomorrow and will post some results. It's getting late here...

[DaForce]

Hey, good start!!

Yeah i see what you mean about the glass, scanning really ruins it.

Hopefully your bump box will work well. Just dont move the camera at all!!!

Hehehe im tempted to make something similar... looks very interesting.

[flipside]

You could also try to put very thin paper on the glass, then rub some fine carbon powder (from the tip of a pencil) over it. The high parts will be darker grey than the low parts. Then scan that in and mess with it in photoshop untill you have a nice bump map.

I did this once with the texture on a plastic part, and it worked pretty well. Don't know if it works well with not-random bumps like your glass drawings.

[CCS]

What about making a casting of it with play-dough, clay, plaster, or something. Then take your bump photos of that object.

[DaForce]

Yeah i was thinking of that as well, cause he wont be able to really get any shadows on those glass tiles. I was thinking either a plaster cast of the glass tiles or maybe something similar.

Or if he is able to keep the tiles, it might just be easier to spray paint them white. He can always clean them if necessary.

[CCS]

That's an idea. Much easier too!

Sounds like he's got a boxful. I'd paint a half-dozen or so, then PS a big map.