What is Ray tracing: Definition and 46 Discussions

In 3D computer graphics, ray tracing is a rendering technique for generating an image by tracing the path of light as pixels in an image plane and simulating the effects of its encounters with virtual objects.
The technique is capable of producing a high degree of visual realism, more so than typical scanline rendering methods, but at a greater computational cost. This makes ray tracing best suited for applications where taking a relatively long time to render can be tolerated, such as in still computer-generated images, and film and television visual effects (VFX), but generally more poorly suited to real-time applications such as video games, where speed is critical in rendering each frame.In recent years, however, hardware acceleration for real-time ray tracing has become standard on new commercial graphics cards, and graphics APIs have followed suit, allowing developers to add real-time ray tracing techniques to games and other real-time rendered media with a lesser, albeit still substantial hit to frame render times.
Ray tracing is capable of simulating a variety of optical effects, such as reflection and refraction, scattering, and dispersion phenomena (such as chromatic aberration). It can also be used to trace the path of sound waves in a similar fashion to light waves, making it a viable option for more immersive sound design in video games by rendering realistic reverberation and echoes. In fact, any physical wave or particle phenomenon with approximately linear motion can be simulated with these techniques.Path tracing is a form of ray tracing that can produce soft shadows, depth of field, motion blur, caustics, ambient occlusion, and indirect lighting. Path tracing is an unbiased rendering method, but a large number of rays must be traced to obtain high quality reference images without noisy artifacts.
Hybrid ray-tracing is a combination of ray-tracing and rasterization.

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  1. D

    Looking for trigonometric ray tracing software for optics

    Is there an existing ray trace program that can trace planar light rays through this monocentric, model lens? Parameter values are given above. Input ray angles are all zero. Does some program give the output ray angle values at the second surface? How about for any arbitrary ray incoming to...
  2. P

    Find pupil locations w/ paraxial ray tracing (thick lens, Geary CH 5)

    Per the description given in the book, one can trace rays FROM the physical aperture stop into object space to find the size and location of the entrance pupil (EP). Also, one can trace rays FROM the physical aperture stop into image space to find the size and location of the exit pupil (XP). In...
  3. P

    I Paraxial ray tracing: fixing image/height w/o knowing stop location

    In recent coursework, I was taught that one locates the image and identifies the image height using the marginal and chief rays. These descriptions are: Marginal ray: that ray traced from [top or bottom] of the object, through the outermost edge of the stop. The place where that ray crosses the...
  4. K

    A Ray Tracing Simulator: Simulating Gaussian Beam in Bow Tie Cavity

    Hello! Is there any good free ray tracing simulator? I just want to simulate the behavior of a Gaussian beam in a simple bow tie cavity. Thank you!
  5. E

    I Ray tracing in the movie Interstellar

    https://arxiv.org/abs/1502.03808 They are using Boyer-Lindquist coordinates for the Kerr metric. As far as I understand they also introduced a camera-fixed basis defining spherical coordinates ##\theta_{cs}## and ##\phi_{cs}## to keep track of the directions of the light rays relative to the...
  6. P

    Ratio of the Earth's core radius to total radius via seismic turning point

    I've attached a figure I've made; I know I'm to assume the Earth is a perfect sphere in this case. Assuming the 103 degrees is measured as latitude, I've calculated the distance in kilometers (Xp in the second equation above) to be 1.1453e4 km. I know I need u = p at the turning point, but not...
  7. Tone L

    Optical Measurements of the Sun's radiance and ray tracing

    Summary: This is a hobbyist project I am working on. I am building an instrument to measure radiance from the sun at 500 nm, using optically filtered photodetector with bandwidth ± 10 nm. This type of science can be called Sun Photometry, so let's get to it! Geometry for Optics: The sun has an...
  8. V

    Second reflection angle of incidences in 3D

    Given Theta1(angle of incidence) and alpha1(azimuth angle). how do we obtain the second reflection angle theta3 and alpha3? Assuming the surface to be a mirror reflection(theta1 = theta2). Need an equation when varied the incident angles we would obtain the second reflection angles or a method...
  9. P

    Finding the height of a focus point via ray tracing @ Snell's Law

    So far all I can work out is that the angle of incidence of the outer two and inner two rays is zero degrees, however, I can't work out how to get started on the problem. I feel like I need to use vertical slowness rather than the normal snell's law since I'm working with a dZ rather than a dX...
  10. M

    Numerical aperture of a Keplerian telescope

    Homework Statement [/B] Design an afocal Keplerian telescope to imagine an object of ##L = 5\, mm## with a resolution of ##R = 2\, \mu m## and a magnification of ##M=-2##; assume that the wavelength is ##\lambda = 500\, nm##. Don't use lenses faster than ##F/1##. Using the optical invariant...
  11. A

    Is there a limit to how steep the refractive index gradient can be

    Is there a limit to how steep a refractive index gradient can be before ray optics are no longer able to predict the path of the light? How is it related to wavelength? Under what conditions the light will be able to travel perpendicular to the gradient In a straight line? (having diffrent index...
  12. ytht100

    Infinitesimal, Snell's law, and ray tracing

    With FIXED SOURCE AND RECEIVER, I have a light incident from fluid 1 with velocity v1 into fluid 2 with velocity v2. Obviously, according to Snell's law, v1/v2=sin(alpha1)/sin(alpha2), where alpha1 and alpha2 are the angles with regard to the vertical line. My question is: how to calculate...
  13. mester1025

    Ray tracing with transfer matrix method

    Hi, I'm new in physics and optics so I need a little help. I've a simple optical system from 2 thin lenses. The first thin lens has a focal distance of 50 [mm] , and the second one has 25 [mm]. The 2 lenses are separated by 40 [mm] and the object is placed 75 [mm] before the first lens. I've to...
  14. S

    Convex Lens and Magnification

    Homework Statement You wish to obtain a magnification of -2 from a convex lens of focal length f. The only possible solution is to: A) place a virtual object at a distance 2f/3 from the lens. B) place a virtual object at a distance 5f/3 from the lens. C) place a real object at a distance...
  15. J

    Ray Tracing - Optics - Bend light with circular lenses

    Hey guys first time poster. I have written a 2D ray tracer in Mathematica. It's very basic, all it does is use Snell's law to trace ray refraction and very basic absorption. The set up is a central absorbing circle surrounded by circular lenses. The central circle is a perfect absorber, so if a...
  16. C

    Index of Refraction Through a Cylindrical Tube

    Hello All, I would like to start learning how to ray trace but the tracing through a tube with a thickness of t has got me stumped. If I have an n1 (outside tube), n2 (Tube), and n3 (inside tube). n1≠n2≠n3. Knowing Θ1 (the angle of incidence in relation to the normal), I can calculate Θ2 from...
  17. O

    Hand drawn ray tracing through an optical system

    Hi, I am familiar with drawing rays through a lens. But when a few lenses are put together, things become confusing to me. For example, if a first positive thin lens at 0 forms a real image 10cm away, what would happen when we put a second positive thin lens, say at 5cm along the optical...
  18. T

    Ray tracing concave mirror

    Homework Statement B) Using the mirror equation, find the image distance. Homework Equations 1/do + 1/di = 1/f The Attempt at a Solution [/B] B) do = 2cm f = 4cm 1/do + 1/di = 1/f 1/di = 1/f - 1/do 1/di = do/f(do) - f/f(do) 1/di = (do-f)/(f*do) di = (f*do)/(do-f) = (4cm * 2cm)/(2cm - 4cm)...
  19. T

    Ray tracing for convex lens

    Homework Statement [/B] B) Is the image real or virtual? Explain. C) Using the lens equation, find the image distance. 2. Homework Equations 1/di + 1/do = 1/f The Attempt at a Solution A) B) The image is real because it is on the opposite side of the lens as the source of light. C) do =...
  20. A

    Ray Tracing and Combination of Lenses

    I was looking at this problem. Does the problem assume that the focal point of the divergent lens is right next to it? The answer is c, saying that the focus point will be further away: but that assumes that the focal point is not RIGHT NEXT to the divergent lens. If it were RIGHT NEXT (VERY...
  21. jlefevre76

    Ray tracing vs. experimental data

    So, here's the deal: I'm trying to complete the publishing of a paper dealing with my thesis from almost two years ago, and I finally wrote a program that I believe will tell me how different geometries will influence the outcome. Here's the setup, I am modeling the radiation that goes through...
  22. K

    Ray tracing- Is luminance being traced?

    My understanding of ray tracing is that it maps out luminance for a scene. Now with ray tracing (backwards ray tracing that starts from the camera outwards) does each ray have a luminance value associated with it? In the case of a perfectly diffuse surface, can one simply take the mean of all of...
  23. tom.stoer

    Black hole collapse - ray tracing

    I know several raytraycing results for static Schwarzschild black holes, but I have never seen something similar for collapse models like Oppenheimer-Snyder or Vaidya. Are there reliable raytraycing results showing the effect on light rays from far distant light emitters observed by (far...
  24. A

    Ray tracing, regarding Turner Whitted's original paper

    As many of you may know, ray tracing was first introduced by Turner Whitted in 1979 in a paper titled "An improved illumination model for shaded display" (can be found on ACM digital library). On the 2nd page, in part 2 (Improved Model) there are a number of fairly simple vector calculations...
  25. S

    Looking for ray tracing and surface optimization suggestions

    I am a physicist who is interested in acoustic guitar design (additionally I make custom made guitars and violins). The problem I have is in acoustic guitar design, for simplicity imagine a box 20"X15"X3" (length, width, depth). On one of the 20X15 surfaces (the top) cut a 3" hold 1/3 from...
  26. I

    Ray Tracing in Plasma: Wave Propagation in Ionosphere

    I'm studying wave propagation in the ionosphere, which can be modeled as a dielectric that has a magnetic field present. My understanding of it is that the Poynting vector that is associated with the wave in the medium is not generally in the same direction as the k vector (what I understand to...
  27. T

    Ray tracing through optical system of thick lenses

    Can you advise me a free software that allow to draw rays passed throught system of thick lenses (preferable in 3D)?
  28. C

    Ray tracing - how to numerically integrate the equation of the ray

    In a continuous isotropic medium having refractive index n, (not constant) the ray path can be described by the following equation d/ds(n dr/ds)) = grad (n) with an obvious meaning of the symbols (for they who can help me!). I wrote a code to calculate the ray path. I found result...
  29. phosgene

    Ray tracing diagram for white light moving through glass

    Homework Statement White light is incident on a sheet of glass as shown below. Complete the ray tracing diagram. Homework Equations n1(sinx)=n2(siny), where n = the refractive index of the medium. The Attempt at a Solution The ray on the bottom is hitting the glass at 90 degree angles...
  30. M

    What is the formula for the angle of deviation in a thin prism?

    I finally found something about thin prisms on the web I don't understand whether the angle of deviation depends on a the angle of incidence in a thin prism or not? Is the thin prism always in the position of minimum deviation?
  31. A

    Ray Tracing and Lens Formula for Image Location

    Homework Statement An object is locted 15cm infront of a convae lends with a focal length of 10cm. use ray tracing to determine the location of the image. try to draw to scale i)is the image upright or inverted? ii)is the image real or virtual? iii)use your ray-tracing diagram to...
  32. S

    Ray Tracing with Diverging and Converging Lenses: A Quick Guide

    If I have an object and in front of it there's a diverging lens, and in front of that (furthest from the object) there's a converging lens can I just ignore the diverging lens when ray tracing for the image formed by the converging lens? I figure if I were able to draw an infinite number of...
  33. R

    Ray diagrams for mirror ray tracing

    Just a check here... I'm doing some ray diagram practice for optics and I've hit a road block. Hyperphysics is stating that for a concave mirror o is usually negative due to it measured against the direction of light propagation when applied to the mirror equation (below)...
  34. N

    Intersection test for ray tracing

    I know that intersection tests can typically (for hit detection in games) be computed in log n time with reasonable accuracy, but there is a problem that I see with using hierarchical bounding volumes in ray tracing. For example, a ray may intersect a bounding volume however due to the shape...
  35. K

    Ray Tracing Rules: Concave & Convex Lenses & Mirrors

    Can anyone brief of on the different rules for doing ray tracing for both concave and convex lenses, as well as both concave and convex mirrors?? I understand the concepts but i can't seem to keep ray tracing in my head from the way our textbook explains it...
  36. C

    Concave Lens Ray Tracing

    Homework Statement I have a concave lens where f < do < R. I have to provide a ray tracing diagram. The Attempt at a Solution I drew the focal ray through the focus and parallel to the principal axis. I drew the principal ray parallel to the principal axis then through the focus. I...
  37. B

    Ray Tracing and Image Formation with a Concave Lens

    Homework Statement If the focal length of the concave lens is -7.50 cm, at what distance d_o from the lens should an object be placed so that its image is formed 3.70 cm from the lens? What is the magnification m produced by the concave lens described in above? Where should the object be...
  38. J

    Use ray tracing to determine the location of the image

    Homework Statement An object is 6.0 cm in front of a converging lens with a focal length of 10 cm. Use ray tracing to determine the location of the image. Is the image upright or inverted? Is it real or virtual? The Attempt at a Solution According to my ray tracing...there is no...
  39. W

    [Ray Tracing] Wavefronts & Reception Sphere

    Hi all, I'm confused about the concept of wavefronts in ray tracing .. each ray is considered a wavefront? or what exactly is a wavefront in ray tracing? In the reception sphere, it is mentioned that only one ray should be received from an actual path. I don't get it .. does this mean that...
  40. W

    [Ray tracing] Resultant of electric field components

    Hi All, I am a beginner at Electromagnetics I'm implementing ray tracing SBR to predict propagation of waves. Each ray contribution will be in the form of: Ei = (some factors) e ^ (- j k r) u(theta, phi) where k = 2 pi / wavelength, r is the total unfolded path I'm not sure about...
  41. E

    Optical Ray Tracing - "Y N U" Method & Aperture Stops

    Is anyone familiar with the "y n u" ray trace method for optical systems, using paraxial rays where Snell's law is approximated using: n1sinx1 ≈ n1tanx1 ≈ n1u1 = n2u2 If anyone is familiar with this, I'd be interested to discuss the finer points of "a-ray" and "b-ray" tracing, as well...
  42. B

    Multi-Lens System Ray Tracing -Please help

    Multi-Lens System Ray Tracing --Please help Homework Statement It isn't possible to form an image of a real object on a screen with only diverging lens. However, if we use a converging lens, it is possible to create what is called a virtual object. The diverging lens has a virtual object...
  43. B

    Solve Ray Tracing Problem: Image Location for 6.3 cm from Convex Mirror

    Ray Tracing...HELP! Homework Statement An object is 6.3 cm from a convex mirror with a focal length of 10 cm. Use ray tracing to determine the location of its image. Homework Equations The Attempt at a Solution 1/f = 1/s + 1/s' 1/f - 1/s = 1/s' 1/10 - 1/6.3 = -0.0587 cm ^ -1 =...
  44. H

    Ray Tracing Box Intersection: (3,8) to (6,-1), (-2,3), and i-5j

    Ok, so this is probably a really basic question, and I've got a feeling that my brain is just too 'fuzzy' just now and that all my problem is is simple arithmetic, but here it goes... 1. Determine whether or not the box with vertices at (2,1), (5,1), (5,5), and (2,5) is intersected by the...
  45. frankR

    Ray tracing with matrices

    Here is the problem: A glass sphere with a diameter of 5cm has a scratch on its surface. When the scratch is viewed through the glass from a position directly opposite, where is the virtual image of the scratch, and its magnification? The glass has an index of refraction n=1.50. Explain the...
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