Any chance we could get a tool that traces refraction rays through a surface or solid? I’m working with glass lens designs, and something similar to Bounce cmd would be fantastic, for showing refraction of light rays through glass material. Obviously different types of glass (or whatever material) would have different refraction properties, but at least showing how light rays pass through clear glass surfaces would be a very helpful tool. I already use the Bounce cmd for reflections, and that’s helping me out immensely.
thanks!
David
Hi David, I guess this would be a scriptable thing but there is no built in tool for it. How would you envision it would work- would you assign IOR to objects and fire a ray from a user input point in a user input direction and then see the ray as lines traced through the surfaces, something like that?
-Pascal
Yes, that’s exactly how I would see it. Every object would need an IOR assigned, then it would work exactly like Bounce.
Faceting for Amateurs volume 1 and 2 should get you pretty much everything you need to know. Along with trig, computer programs for ray tracing, optimizing, etc…
Believe it or not, understanding why people see in color, predicting how light interacts and refracts, disperses, diffracts, produces any forms of pleocroism, interacts with electromagnetic particles (a part of light ray) to display pleocroism, viewing axes, speed of light that never ends and accounts for how we see, why we don’t see individual light rays bouncing all the time, etc…Are kinda tricky to learn if ya catch my drift.
I make glass, and glass itself has many considerations in how a light ray reflects. Why does a prescription lens look different than window glass when viewed through the facet or “The window” that you look through. Or the angle in which you are looking at it, and where the facet is.
Snells law, air as 1 side of equation, differing refractive indice other than air for the other side of equation. What helped me understand, is a doublet or triplet gem. Part emerald, part glass, and air. The snells law goes through three refractive indices, and it calculated 2 or more times. Air has a refractive indice.
Inclusions
Glass Formula
Dirt particles on surface
Blemishes
Scratches
…
What kind of rays, and what kind of reflection? You talking the white light direct reflection that is so highly prized in the gem industry???That was a joke.
I’m just playing around. But if you ever wanted to get down on light rays, everything I mentioned is childs play in comparison to really getting down on your light rays and glass!
But these programs could be of use to you. Gemray and BOG Optimization.
Also, check out every book you can and buy every book you can regarding topics such as
Advanced Approximation Mathamatics…
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Well that’s all fine and dandy, but I use Rhino, and I’m looking for this functionality in this software. According to Pascal, it is very possible. I’m glad you have so much knowledge into making gemstones though.
Because of the curvature and thickness of the lens - curved lenses are going to have a focal length, whereas straight windows will not. One of the things I do is work with optical lenses for lighting purposes btw.
-d
Yup, I was just referring to the vast amounts of areas of study for how light shows through glass. Not being a smart you know what, just being me an listing some of the factors. And since I don’t know of rhino’s capabilities, I figured id point out some areas that would help you determine the angle of the dangle.
But even with any of the software mentioned, approximations are used. I was at a book store and skimmed a book on various ways of approximating using so much stuff I could never understand. But I knew that something like that book contains information needed to program a program such as the BOG which does a pretty good job of optimizing exactly how you want your shine, and what happens when you turn 1 of roughly 10-50 facets by 1 degree.
I’m sure you have a lot of knowledge in the field, and I do not mean to insult anyone but listing my areas of current study. I am curious as to your answer as well.
In optical lenses, whooo boy, there’s a lot. As a glass jeweler who simply tries to create cool looking lighting effects in conjunction with the best shapes, colors, varying sparkle materials, varying densities of glass color/opacity/saturation, varying amounts of gas ratios, physics, laws of heat/convection/radiant, hand skill, patterns, etching, sandblasting, faceting, I would say I got it pretty easy. But calculating, and combining known flameworking methods with experimental methods, combined with faceting and light ray knowledge and the fact that no one has ever written a semi-serious book on glass jewelry(bead books do not count!), a single pdf document on light interaction with glass art, or would ever reveal their jewelry secrets I do have to use a little creativity!
Optical lenses is a a very serious science though. The categories that go into them, scia, and all kinds of science beyond a glass artists is pretty incredible. The worst thing a glass artist has to worry about is someone getting cut, the worst thing a optical glass manufacturer has to worry about is taking the # 1 life gift of sight. Needless to say, optical glass manufacturers should be a little more educated. Wearing dollar store sunglasses is very risky!
Also, you noted glass having different refractive properties. This is a thought and concern of mine as well. Glass flameworking for art involves using combinations of 1 of 20 or so formulas of clear borosilicate and 1 of 400 different colors. So if you combine say, 10 formulas of color or clear in your art, accurate light tracing is quite difficult.
Next is opacity and its correlation with gas ratios, length of time heated at a given temperature, location in the flame, actual mass(larger 1 inch marble will appear a darker translucent red than when that red is thinned into a 2mm rod) and of course the interior shapes. Next is inclusions in the glass, bubbles, pitting, checking. Next is getting the interior things that light bounces off of a consistant shape that can be predictated or setting parameters to repeat a light bounce.
On, and on…Plus I might wanna retain a couple ideas in my head.
So, I too wonder. But it does seem that you would be able to calculate the light ray bounce, with the refractive indice of the glass formula you are designing a little more predictable than me. Using precision machinery, and only having 1 boundary to plug into snell’s law makes it more simple than the calculations mentioned above.
The light will pass through, it will bend according to refractive indice, and few other factors go into the calculation.
As I know, and as stated in the faceting books. You can really only rely on computers so much. If you know the science behind the computer’s calculation, along with the computers calculation, you will be able to spot mistakes made by the computer. Or the user. Lets say one of your boxes was checked wrong, and you wasted 200 bucks on a prototype and wasted time not knowing the computer made a mistake.
So, combine the sciences with the computer, double check, and be aware of all the computer options and you’ll be better off.
I might be pm’ing ya for a few questions relating to the subject of light and glass though and I am not aware of how scientifically involved you are. Anywho, hope you find what you are looking for. I’ve determined for me, a good start is learning trig, brushing up on algebra and geometry which will definitely help in 3d modeling, gemology, engineering, machining, tool-making, goldsmithing, and glassworking. In fact everything you know adds creativity to everything else you know by applying similar concepts.
The next thing that baffles me a bit, is what exactly is the ray? In rhino, a ray will come from the light position. The angle will depend on where the light is, and where your model is, and how the model is rotated.
Is the result you are looking for, a single ray? Or are you looking at making 1 ray path for each light position.
Say, 100 different light positions, 100 ray paths? Or are you planning on the light being perpendicular to the absolute top center of your optical lens?
So, what are your plans with the angle of the light source, and where you will view the light path from? There are different ways of representing light paths and reflections. Say for instance, a particular angle that will blind you.
Also, what are your plans with how you would like to view it, and what is the use of the light path study?
This would all affect how you would like your light path displayed.
I also now realize you are referring to rhino objects in general. Not a overhead projector lens with a dome like I am envisioning! You might wanna see how it will bounce through a tube with angled walls and reflectors or something?
Or like a entire microscope with a darkfield half dome reflector or something.
I will also say this. This area of study is of particular interest to me because I have at least pieces of glass jewelry which have created effects that are very very desirable in terms of a gem. I am learning to reproduce these effects. So, any knowdlege I can aquire would be of use.
When I am able to reproduce these gems made via magic, I will be very very happy. Until then they shown to a select few. I can either let magic happen, and put a price tag on it that says $500,000 only gem in the world or learn to reproduce and be the only supplier of such effects until my secrets are revealed. In a sense, I am seeking tolkowsky like knowledge and one day my process could be that reproduced by someone else. Afterall, a gem faceter would only need a physical model to take human measurements in order to reproduce them. The brilliant cut, is now a norm. What I can produce is would hold that special value until imitators duplicate. Anywho, I’m sure your light optical lens feels the same way to you. This same would go for anyone working on their bankers boxes of million dollar inventions, ideas, sketches and designs. As for that million dollars…a couple books need to be read here and there!
Also, in a sense even having all these terms in one thread could dispose my secrets and my competitors could benefit from these ideas. You could even be a glass jeweler in disguise, seeking my knowledge and secrets. But, I contribute to my competitors anyways, always have. Afterall, they are just ideas and it takes a lot of work to even steal someone’s idea and beat them too it. Not many people have the drive, and life aint all about money anyways. To me its about specialness, and spreading the feeling of specialness. If I have to aquire rough, make a custom tool, a custom jig for the custom tool use, a custom tool holder to use when I am fabricating it, design the best gem cut I can, with the best design I can, model in 3d, cnc, cast, fabricate, and set a gem to make someone feel as special as I do, then so be it. Whatever I gotta do to not be some art fair hippie who glues stones to Chinese findings and somhow sleeps at night. Commercial made products just don’t meet special standards, and are not special in any fashion. (Insert that’s why he didn’t go to ja–d joke here)(I got plenty, and there’s a lot of cheap dates out there!)
But, back to light ray tracing in rhino. The above is relevant to a degree. Your goals, purposes of creating 3d models, your application, and how you aquire knowledge to use in rhino 3d is relevant. If the threads were only 3d, with no application they wouldn’t be quite as interesting. What I have stated about my goals, my plans of using pen and printed design, paper, trig, calculators, and charts to knowledge not contained in rhino threads aquire my light predictions is relevant as well. Forgot the protractor. After all, we all just want a pretty 3d model exactly how we like it, and that’s why we ask questions and discuss methods of achieving goals right?
If tolkowsky can optimize the round brilliant cut with all considerastions accounted for, and change the gem cutting industry, you could probably figure out how to predict a single light path using oldschool methods as well. So, there has to be way, and knowledge is what you seek. I was very excited when I got those two books above as they contain angle gold, gold, it tells you how to grow more gold, and eventually your day is so golden, you have to come up with more ways to spend it. So, I’m spreading some of the gold around. Gold books, check em out and apply to your particular application. The light information is universal.
OK, it sounds like an interesting thing to fool around with, I’ll see if I can make anything useful, I don’t know what’s possible yet, so don’t hold your breath.
My first thought is that objects with no IOR assigned would be ignored, the ray would just pass through them, but I can also see how it might make sense to have these objects stop the ray or even reflect it… ?
-Pascal
Hi Pascal, that’s definitely interesting and fun. Long time ago I made a simple 2D Optics plug-in for a client and also later-on something in 3D for my own design. For practical reasons I found it better to work with surfaces instead of solids cause often materials with different IOR are being combined. But you’ll have to find a way to keep track of the material the ray is inside. Maybe that’s a bit too advanced for a simple plugin?
If you’re having real fun then you can take care about the “total internal reflection”. Have a look at the last picture on this page: http://rhino3.de/_develop/__v3_plugins/optics/commands/Refraction.shtml
Yeah, I was wondering about that. I have an idea or two about how to go about this, but so far ideas only… =)
-Pascal
Thanks Pascal. Just a further note - I really like how the plugin Jess referred to also works on 2D curves. Makes it much easier to set up simple test simulations before committing to building surfaces using those profiles. This functionality would be very useful.
I would think that objects with no IOR would just stop the ray, unless they have some kind of reflection value assigned.
thanks!
Wow, great thread. Thanks for bringing it up, and thanks the information thusfar peeps. Keep up the good work! The plugin pictures and functions are helping me understand and are a great reference in itself, thank you. In my art glass though, 3d modeling each color streak within a lens (blob containing clear glass of any kind, usually dome-like shaped in flamweworker terms) and reproducing would be quite the challenge. With estimation, and engenuity I can increase the odds though. Luckily the shapes can have slight proportional variance and still produce nearly the same light patterns.
In the case of asterism in gems, the proportions of the inclusions must be completely parallel in symmetrical patterns that only humans with tools, and a natural crystal habit can produce.(too look like a perfect star).
Its amazing how nature works in ordinance with mathamatics to produce anything physical in the universe, and how life has came to be in this system…
So it seems to me, that how you project the plugin for v3 working or think it would work for 2d profile curves is that you are
-assuming the light after the first bounce is coming from a direction on the same side of the incident rays. Here I am not sure what shape your intended test shapes will look like where the 2nd bounce is to take place. I only have reference to culet thus far in my text, which is the bottom shape coming to a point in gems.
In my texts, another area or factor that would come into play in your calculations is the capture cone. The capture cone being where light enters or can enter with relation to the incident rays. With the capture cone referring to any of the top facets as light entry points from a given incidence angle to contribute to the total amount of light. It seems that the capture cone directly affects how much total light is possible to enter the profile or 3d shape. In the gem texts I have, this would include the top table, and any facets able to be penetrated by the incident ray.
I am not sure, but trying to understand and make sure I understand the reference to a capture cone though. So, if your profile were a dome, would its capture cone would begin at the incident ray and extend to the other side of the dome or mirrored(rhino terms) across the x,z axis(world coordinates)? (or in 2d side view of profile, the x, y axis)
In which the angle of incidence could be a number from… angle of incidence
through
to a maximum of 90 degrees would determine the capture cone size.
So, is there a mximum to the indent ray angles? Am I correct in thinking the maximum incidence angle is 89.9999 degrees?
IE, angle of incidence =45 degrees
Subject: A perfectly spherical top on a dome, or (a marble split in half)
Would the capture cone be 45 degrees?
It seems, that we have different goals here though. You (dwalden) may want to study light passing through, whereas I would want to calculate light trapped.
Would capture cone apply in your calculations at all dwalden?
I am also curious. Would your designs only include smooth rounded single surface domelike designs, or like eyeglasses with curved plate like shape?
So in your light calculations, measuring total light would be a consideration??? Thus surface area as well and mathamatics beyond light path projections going into design considerations? Or is one of your only considerations in profile of a design how the light reacts with the shape? Aesthetics?
@thinslicevolta the angle of incidence is relative to the normal vector at the point where a ray hits the surface. Hope the attached picture helps: 