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hey there,

here is a test i am doing with the new pmc kernel. and i'd like to know how i can create something like a parallel light source?? i have now created a long tube where i have placed a plane as a lightsource. however, it still creates something like a spot light. how can i create a laser light??

cheers,
ello

http://science.howstuffworks.com/laser4.htm

try read more about lasers, its different then oridanary lights !

And i dont know how to do this in octane



Laser Light

Laser light is very different from normal light. Laser light has the following properties: •The light released is monochromatic. It contains one specific wavelength of light (one specific color). The wavelength of light is determined by the amount of energy released when the electron drops to a lower orbit.
•The light released is coherent. It is “organized” -- each photon moves in step with the others. This means that all of the photons have wave fronts that launch in unison.
•The light is very directional. A laser light has a very tight beam and is very strong and concentrated. A flashlight, on the other hand, releases light in many directions, and the light is very weak and diffuse.

To make these three properties occur takes something called stimulated emission. This does not occur in your ordinary flashlight -- in a flashlight, all of the atoms release their photons randomly. In stimulated emission, photon emission is organized.

The photon that any atom releases has a certain wavelength that is dependent on the energy difference between the excited state and the ground state. If this photon (possessing a certain energy and phase) should encounter another atom that has an electron in the same excited state, stimulated emission can occur. The first photon can stimulate or induce atomic emission such that the subsequent emitted photon (from the second atom) vibrates with the same frequency and direction as the incoming photon.

The other key to a laser is a pair of mirrors, one at each end of the lasing medium. Photons, with a very specific wavelength and phase, reflect off the mirrors to travel back and forth through the lasing medium. In the process, they stimulate other electrons to make the downward energy jump and can cause the emission of more photons of the same wavelength and phase. A cascade effect occurs, and soon we have propagated many, many photons of the same wavelength and phase. The mirror at one end of the laser is "half-silvered," meaning it reflects some light and lets some light through. The light that makes it through is the laser light.


check link from up and mybe this metod with half-silvered mirror

the reason you're not getting the desired result with your tube ello, is that your plane light is bouncing off of the inside of your tube.

the closest thing you'll get to a narrow beam of light is using ies lights. there's free ies generators out there that let you create your own ies files - in case you can't find one that's narrow enough for you.
not exactly an answer to your question in know, but still somewhat helpful i hope.

thanks to both of you. bouncing shouldn't be there since i have an inner tube with diffuse material and color of "0 0 0"...

i'll try using an ies light, this sounds like a good idea

You can use geometry and a blackbody.

i think you might be wrong there ello - if i understand you correctly that is.
a diffuse material still bounces light. a small tube does so too.

just do a longer cannon to narrow the diameter of the spotlight

i don't think that's the best approach proupin - and would just introduce a LOT of noise.

Three, different length cannons and the beams they produce. I'm doing a render of these same beams with some obstacles... post or edit later...

the diameter of the beam is determined by the cannon's diameter. Make it very narrow and long, like a 1:10 ratio between diameter/length; The cannon interior is bouncing nothing because its a diffuse black material.

nice one proupin.
i stand corrected.