What is tracing: Definition and 85 Discussions

In 3D computer graphics, ray tracing is a technique for modeling light transport for use in a wide variety of rendering algorithms for generating digital images.
On a spectrum of computational cost and visual fidelity, ray tracing-based rendering techniques, such as ray casting, recursive ray tracing, distribution ray tracing, photon mapping and path tracing, are generally slower and higher fidelity than scanline rendering methods. Thus, ray tracing was first deployed in applications where taking a relatively long time to render could be tolerated, such as still computer-generated images, and film and television visual effects (VFX), but was less suited to real-time applications such as video games, where speed is critical in rendering each frame.Since 2019, 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 use hybrid ray tracing and rasterization-based rendering in games and other real-time applications with a lesser hit to frame render times.
Ray tracing is capable of simulating a variety of optical effects, such as reflection, refraction, soft shadows, scattering, depth of field, motion blur, caustics, ambient occlusion 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 ray tracing.
Ray tracing-based rendering techniques that involve sampling light over a domain generate image noise artifacts that can be addressed by tracing a very large number of rays or using denoising techniques.

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  1. I

    Help with proper grounding with oscilloscope tracings

    I am having some issues when viewing tracings of my induction heater tank. It has to do with the grounding. First, I will explain the situation; then, I will ask the question. The images show the inverter voltage in yellow which results in a current in light blue. The dark blue is the 90 deg...
  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. H

    A Does partial tracing make us see things that do not occur?

    Hi Pfs Partial tracing maps what occurs in a big Hilbert space toward a smaller one. We have to use it when degrees of freedom are physically unobservable or when we have only a coarse grained view of the environment. it is like in Flatland , where the two dimensional inhabitants has no access...
  6. A

    Tracing correct words from Jumbled words using machine learning

    Can we trace all correct words from Jumbled words using machine learning prediction, search algorithms? https://builtin.com/machine-learning/nlp-machine-learning Input Dataset : Jumbled words. Jumbled word example: oolp Output : pool, loop, polo.
  7. bhobba

    COVID Will a High Vaccination Rate Affect Contact Tracing?

    I heard an immunologist say the other day that once a high vaccination rate is achieved, contact tracing will likely not be effective. I can sort of understand why. Does anyone from places with a high vaccination rate know if contact tracing is still an effective measure? It is very widely...
  8. 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...
  9. Ryan_m_b

    Is Contact Tracing Without Personal Data Collection Possible?

    Thought the members here might like this explanation on how contact tracing apps can be made that collect no personal data. The design is quite clever at preventing situations where centralised databases collect information like who you are, where you’ve been, who you’ve met etc.
  10. suezxc6

    Comp Sci How Does This Fortran Code Generate and Output Its Array Values?

    integer n, ar(12) ar(1) = 1 ar(2) = 2 do n=1, 10 ar(n+2) = ar(n+1) + ar(n) end do do n=0,3 print*, ar(12-3*n) end do print*, ar(ar(ar(4))-1) end
  11. 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...
  12. 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...
  13. S

    MHB Discrete maths problem - tracing an algorithm

    Hello, I'm working on a discrete mathematics for computing paper and am stuck on what a symbol is trying to convey. Sorry if this seems like a stupid question (I feel stupid for not being able to work it out myself), I've just started this subject and am still getting used to it. My question...
  14. Brilli

    Efficient Path Tracing: Solving for Time and Motion with Inclined Planes

    Homework Statement A small disk A is placed on an inclined plane forming an angle (alpha) with horizontal and is imparted an initial velocity v. Given coefficient of friction =k and ant initial moment angle of velocity =90 degrees. Find out how long it takes to come ro rest and give the...
  15. 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...
  16. Spinnor

    Tracing a ray of light through a spiral phase plate

    Draw a single light ray through a spiral phase plate, anywhere but the middle of the plate, with the incoming ray being parallel to the axis of the spiral phase plate. On passing through the plate the ray is no longer parallel to the axis of the phase plate? Does the change in direction account...
  17. N

    Java Recursive Tracing Java: Learn How to Trace a Method

    It would be much appreciated if you could show me how to do recursive tracing for this method.
  18. S

    Tracing object trajectory through a photocamera

    Hi all, I need to trace the trajectory of a moving object. The object are yellow and opaque while the background is grey. Since I'm interested in the shape rather than the exact coordinate, I'm wondering if I could use the light painting principle to impress on a photo the trajectory. How could...
  19. Marcin H

    Nested Conditional Constructs (TRACING) Confusion

    Homework Statement Manually[/B] trace the following code segments assuming that x equals 12. Show exactly what would be displayed on the terminal. if (x > 0) { printf("x>0\n"); if (x < 10) { printf("x<10\n"); if (x == 12) { printf("x==12\n"); } }...
  20. F

    Box structure tracing experment

    I want to do an experiment where I follow the particle in all trajectory until it hits the wall of the box, then I want to draw out this box's structure based on the particle collision. One thing would be that the particle does not need to go in all trajectory, but I would like to know how to...
  21. A

    Tracing back an electromagnetic wave to its source

    Suppose you have a solution to the Maxwell's equations in vacuum, and now you want to find what kind of charge/current system create the wave in the first place, can this be done?
  22. 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...
  23. Illicithunter

    School project for tracing radio transmission

    I need to trace a simple radio transmission for school. It's a signal that is broadcasting some talk radio. If I could locate the signal within a couple hundred feet I get an A. Extra credit is for jamming, re-directing or scrambling the signal. Any ideas for any of the said process. It's...
  24. Borek

    History Uncle Mietek: Tracing Family History in a Military Cemetery

    When I was a kid my Dad told me stories about uncle Mietek – brother of his mom (and my grandmom). Not that he remembered him – uncle Mietek joined Polish Army somewhere in nineteen thirties, went to Military Academy, and was killed in early September, just a few days after the WWII started. Dad...
  25. 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...
  26. 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...
  27. T

    What is the image distance for a concave mirror using the mirror equation?

    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)...
  28. T

    Ray Tracing for Convex Lens: How to Determine Image Distance and Realness

    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 =...
  29. T

    The Power of Weakness: Tracing Human Evolution

    Is physical weakness the catalyst that started Human evolution?
  30. S

    Question about reverse tracing the Einstein field equations

    From what I know, to get the reverse trace form of the Einstein field equations, you must multiply both sides by gab (I didn't have a lot of time to make this thread so I did not spend time finding the Greek letters in the latex). This turns: Rab- \frac{1}{2}gabR= kTab (where k=...
  31. 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...
  32. 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...
  33. M

    Tracing a laser pointer with IR camera

    Hi! a very basic question that probably has a simple answer: would it be possible to trace a laser moving over a generic surface such as a wooden floor with an IR camera? The idea would be to calculate relative movement based on that... If I'm not clear enough feel free to follow up with a...
  34. F

    Help comsol particle tracing

    Hello, I would like to simulate a beam of light that is incident on a sphere with a refractive index and you get the total internal reflection, I would like to use ray tracing in COMSOL 4.3a. you have any advice on this? thanks
  35. Saitama

    Mass hanging by spring tracing a eight shaped curve

    Homework Statement A mass ##m## on the end of a light spring of force constant ##k## stretches the spring to a length ##l## when at rest. The mass is now set into motion so it executes up and down vibrations while swinging back and forth as a pendulum. The mass moves in a figure-eight pattern...
  36. Evo

    I've started tracing my ancestors

    My mother's side of the family was professionally done years ago by one of her sisters. But no one knew about my dad's family, or my ex-husband, (my girl's father). I'm using ancestry.com, even though they are expensive, it's easy. I figure I'll find all I can in a couple of weeks, actually...
  37. 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...
  38. S

    Automotive Tracing the Path followed by a car

    I would like to know the calculations regarding tracing of the path followed by a car during turning process. i have the following details , kindly do tell what other information is required and how the equations are formed. front wheel track - 1559 mm rear wheel track - 1605 mm...
  39. 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...
  40. 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...
  41. 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...
  42. 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...
  43. F

    Tracing seismic rays - possible intersection

    This problem is about seismic wave propagation in a non-homogeneous layer over a halfspace. I'm not asking you to solve anything, I've already solved the problem both algebraically and in Matlab. However, the graph that I've gotten mildy surprises me. According to the graph, the seismic rays...
  44. 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)?
  45. Evo

    DNA - Tracing your ancestors out of Africa

    I was watching the National Geographic Genographic Project where they are collecting DNA from people worldwide and tracing their ancestor's migrations around the world. You can be a part of the project by purchasing the Geno 2.0 Genographic Project Participation Kit. I think this would be...
  46. 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...
  47. S

    What Software Is Best for Simulating Particle Trajectories in 3D?

    Hi, I use a numerical method to trace trajectories of particles. I want to program a sort of 'video' type graph. A graph or 3d video or perhaps just 3 graphs (xy, xz, and yz) that would show the position of the ion as the software is run. So my question is this... What software would...
  48. 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...
  49. 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?