This is what we got with version 0.1. Our idea was to make a picture in 3D with an objects, which are identifiable only with abstract 3d imagination.
Then we developed version 0.2. It becomes hard to read. But it gave us the second idea of surface rendering. All following versions uses this idea.
Making Z-ordering for objects now allows to hide invisible places. This is mush closer to abstract 3D imagination. We also desided to add a noise but it's not too cute. Second way of rendering is still under experiments but it's almost clear that we have to get rid of it.
We changed the net schema for surface, not it's hexagonal. Also we desided to start some colors experiments and at least - no line tracing surface rendering. Noise seems to be too bad, it does not allow to read the message, we removed it for a time.
Experiments with colors are continued. This version includes simple light model and the picture finaly looks great and can be readed easily. Well, almost :)
We added random font support (any amount of ttf fonts may be used). And experiments with color are now the main task
We added random surface generation for surface of the chars and for flat background. The problem is that often lights are located in the way, when picture becomes unreadable. This is a not working version, good pictures are too rare.
After defeating several CAPTCHAs we decided to make a CAPTCHA which is hard to break. We call it tEABAG_3D.
Q: Is it opensource?
A: No, sorry. Maybe later.
Q: Can I get it for free somehow?
A: Yes, you can. The condition is: you must place a link to us near each appearance of tEABAG_3D CAPTCHA on your site. Contact us.
Q: How do you do all this pics?
PHP4+GD, nothing more. (PHP5 is OK also)
Q: Can I be sure it's unbreakable?
A: No. No one can give you any guarantees. But we can say - believe the guys who breaks CAPTCHAs, this one is VERY HARD to break. And don't forget that breaking CAPTCHA is not only writing and applying OCR, but sessions issues, etc.
Q: Can I buy it?
A: Definately you can. You can buy the solution, buy sourcecodes, buy ides, buy consultation, buy our souls.
Q: If I'll hire you to break tEABAG_3D, will you agree?
A: Yes. Weekly payment plus your ideas - and we are ready to spend next year on trying to break it.