What is 3d: Definition and 1000 Discussions

In 3D computer graphics, 3D modeling is the process of developing a mathematical coordinate-based representation of any surface of an object (inanimate or living) in three dimensions via specialized software.Three-dimensional (3D) models represent a physical body using a collection of points in 3D space, connected by various geometric entities such as triangles, lines, curved surfaces, etc. Being a collection of data (points and other information), 3D models can be created manually, algorithmically (procedural modeling), or by scanning. Their surfaces may be further defined with texture mapping.

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  1. N

    Reconstruction of a 3D image from layered 2D images

    I am currently looking at constructing a model of a 3D printed item based on a sequence of images of each layer of the print. At the moment the sequence of images are transformed to black / white and run through a Moore Neighborhood algorithm and then a voxel representation of the printed...
  2. fluidistic

    3D Visualization of Temperature Distribution Function

    I just downloaded scilab because Wolfram Alpha wouldn't want to plot the function I'd like. In a physics problem I've found the temperature distribution of a 2 dimensional system. I'd like to visualize this function in 3d. The function I want to plot is u(x,y)=\frac{1}{\pi} \arctan \left (...
  3. P

    Complex 3d vector intersection formula

    ok here goes... In a three dimensional environment. i am standing at point (0,0,0) and there is someone else standing at (10,0,0) I start moving with a velocity of (1,2,3)/s and the other guy wants to meet me. I know that he is approaching the point of intersection at 4m/s (that is...
  4. lonewolf219

    How Do Lines and Planes Differ in 3D Geometry?

    Not quite understanding what creates a plane, and what creates a line in 3D. Are vectors points in the plane with a line drawn from the origin to the point? Are position vectors vectors drawn between two vectors? If a plane is a vector and a point, how is that different from the description...
  5. ElijahRockers

    3D Geometry: Calculate the position of the north star

    Homework Statement Ok I'm able to track one star in the sky, over a period of one hour. We use three measurements to find the angle of the arc traced by the star. The three measurements also constitute two vectors. We can take the cross product of those vectors and it will give us a vector...
  6. S

    Quantum Mechanics 3D harmonic oscillator

    What is the normalized ground-state energy eigenfunction for the three-dimensional harmonic oscillator V(r) = 1/2 m* ω^2 * r^2 Use separation of varaibles strategy. Express the wave function in spherical coordinates. What is the orbital angualar momentum of the ground state? Explain? I...
  7. L

    How to measure power in Ansoft Maxwell 3D ?

    Hi, I would like to measure the power give from a source to a transformer and measure the power consume by a RL component. I see only voltmeter and amperemeter in circuit editor, it's not possible de put wattmeter ? Or maybe there's another solution for find the power ? Thanks in advance ;)
  8. H

    Finding Cosine of an Angle in 3D space

    Homework Statement a) Find the cosine of the angles that the line r = [-3,2,5] + t [2,2,√2 ] makes with the coordinate axes. b) If a,b and c are the angles that the line makes with the x,y and z axis respectively, find the value of cos^2a + cos^2b + cos^2c. c) What is the magnitude of the...
  9. S

    How can I plot a 3D vertical plane in Mathematica?

    I'm trying to plot something like x+y=2 in 3D. The image should look like this: Been trying to do it in Mathematica using Plot3D, but the it treats the input as a function of z. Another example: Plot3D[x=4,{x,0,10},{y,0,10},AxesLabel{x,y,z}] plots z=4, not x=4. A similar thread, with no...
  10. N

    Which software is the best for 3D drawing?

    Anyone can recommend me which software is the best for 3D drawing for piping?
  11. ElijahRockers

    Discover the Length of a Sidereal Day with Just a Star and Time Measurements

    Homework Statement a. Suppose you do not know your location (on Earth) or the direction of north. Now suppose you track one particular star in the sky. You measure its exact position in the sky and record the exact time of the measurement. How many such measurements are necessary to deduce...
  12. A

    C/C++ Making a 3D game in C++ without a game engine?

    I don't want to use any game engine. I want to use only C++ to make a 3D Game. How can I do so? I have made many 2D games, like chess, connect 4, mario, snake, etc. But how do i do 3D and make things like DOOM? I use the OLD Turbo C++ Compiler, not Dev C++
  13. J

    Why 8 probabilities in 3D random walk?

    Why are there 8 possible moves in 3D random walk? With R being the distance from the origin, how is its relationship with the number of steps and dimensionality? Thx!
  14. S

    Calculating 3D Vector Resultant - Suneyna

    Hello All, Please guide me to calculate the resultant of the following two 3D vectors. vec1 =(-0.3960i,4.6660j,15.2610k) vec2 =(-4.1230i,-13.2200j,17.9170k) Thanks Suneyna
  15. C

    How is it possible that 3d orbitals are more contracted than 4f?

    just thinking... the energy of an orbital depends on: a)quantum number n b)quantum number l. an orbital will be of less energy when it's more contracted. So technically, 3d should have a lower energy than 4f and hence be contracted. BUT IT'S THE OTHER WAY AROUND! help? thank you!
  16. B

    3D Printer :Researching 3D Printers for Purchase

    3D Printer! :Researching 3D Printers for Purchase! Hey All! So I have been recently assigned to do some research towards purchasing a 3D printer. I find the idea of 3D printers very fascinating. I'm hoping that I can get some feedback from everyone on this forum to make the best decision...
  17. M

    Calculating stiffness of 3d objects

    I have a problem in the understanding of stiffness. For a simple cylinder with force acting axially, the definition of stiffness works ie Force per unit displacement. but what happens if the cylinder is bent, or even better a plate clamped on the edges with a UDL? In this case displacement would...
  18. O

    Projecting 3D point to 2D / view-point

    Recently I was assigned to implement a procedure involving "3D projections" to "2D space". Supposing that 3D data is stored in a n x 3 matrix X, the final step involves Y=XP, where P is a 3x2 matrix. However, I would need to be sure about the actual meaning of the word "projection" to 2D. In my...
  19. H

    3D cloaking changing gravitational lensing ?

    Do the new optical and time shifting versions of 3D cloaking present a challenge to gravitational lensing as a valid proof of gravity ? Am curious if the time shifting constituent of the theories can mimic the redshifting observed in arcs and lenses also. Seems that with the findings of...
  20. V

    Motion of celestial objects in Spacetime looks circular in 3D how?

    I am confused, how the motion of the planets we observing is circular? The motion of the every object in Spacetime is straight, but as we are watching it in 3D, it seems to be circular. What is the reason behind it? In simple words, how the straight motion of the objects in 4D(spacetime)...
  21. R

    3D stress -strain relationship

    εHi, Based on that hoary schematic cube representation in 3D for stress-strain relationship. Stress tensor {σxx, σyy, σzz, σxy, σyz, σzx} and strain tensors {εxx, εyy, εzz, εxy, εyz, εzx} can be written interchangably. Let's suppose that σzz=σzx=σzy=0 then the reamining terms are written...
  22. H

    Discover the Power of 3D Motion Tracking with Tri Axial Accelerometers

    tri axial accelerometer Hi, I'm doing a project to do with measuring velocity of an athlete. I'm looking into using a wireless tri axial accelerometer. I can't seem to find enough detailed information into how it works. Could you please help!
  23. L

    Proof of stationary points of 3D function

    Homework Statement Show that f(x,y)=g(x,y)h(x,y) is stationary if and only if: g=0 and h=0 OR df/dx=0 and (dg/dx)(dh/dy)=(dg/dy)(dh/dx) (All the d's in the line above should be curly d's for partial derivatives.) Homework Equations The Attempt at a Solution I tried...
  24. N

    Extrema in 3D Problem: Finding Highest and Lowest Points on a Defined Surface

    Homework Statement Consider the surface defined by F(x,y,z)=1/2(x+y)^2+(y+z)^2+(x+z)^2=9 (a) Evaluate grad(F) My Solution: grad(F)=(3x+y+2z, x+3y+2z, 2x+2y+4z) (b) Find the highest and lowest points on the surface (i.e. the points where z attains a maximum or minimum). Problem: So I...
  25. C

    Kinetic energy of Rotating Body (in 3D)

    Ok here is what I did: T=\int \vec{\tau} \cdot d\vec{\theta } = \int\frac{\mathrm{d} \vec{L}}{\mathrm{d} t}\cdot d\vec{\theta } = \int \vec{L}\cdot d\vec{\omega} = \int I_{ij}\vec{\omega}\cdot d\vec{\omega} Where I is the inertia matrix. when I carry that out, I get: T=...
  26. R

    Parametric equation for 3D circle that's off-axis

    Hi. I want to know the equation to draw a circle that's a bit tilted. Imagine a 3D circle that's parallel with the Y axis. Now I want to take that circle and have its center cross through the origin still, but I want it to be θ degrees titled from the Y Axis. I'm using the following...
  27. G

    Circumnavigating the Universe and 3D 'Branes

    I read (or heard or saw) somewhere long ago that if you traveled as far as you could go in the Universe you'd return to the exact same point at which you started. If our U is indeed a 'brane, and the previous statement is true, doesn't that whole circuit of travel ending up back at "point A"...
  28. D

    3D Schrodinger Equation of a Wire for Energy Levels - Quantum Physics

    Homework Statement Given a wire with length a and square base b x b (where a >> b), show that the first 1700 (approximately) levels of the electron in the wire are identical for the one dimensional box, when a = 1m and b = 1mm. Homework Equations I know that the allowed energies of...
  29. R

    How to convert 3d co ords to 2d orthographic?

    I'm still looking into this prior to my older thread and someone has told me of a method that I have quoted below; " All measurements are assuming that the pixel width/height is one) Let fov = the field of view, you can decide how much field of view your user will have from the target...
  30. C

    4d object heavier then 3d object?

    Hello I was sitting and thinking one evening and got this question. In our 3 dimensional universe we have our sun, we know all the parts that makes the sun and how it interact with objects and space around it. If we say that we have a 4 dimensional universe and have the same sun there...
  31. M

    Maxwell 3D eddy current simulation for a cylindrical wire

    Hi, I am trying to do a simulation for the current distribution in a cylindrical conductor wire using MAXWELL 3D. I used eddy current solver and assigned excitation of current 1A at both ends of the round wire. (I set length L=2mm, radius R=1mm) The field plot seems ok, having highest current...
  32. C

    Finding the Mass of a Solid in 3d

    Homework Statement Find the mass of the solid bounded by the cylinder x^2+y^2=2x and the cone z^2=x^2+y^2 if the density is \delta = \sqrt{x^2+y^2} [b2. The attempt at a solution[/b] I had some trouble looking at how to set up the limits on this integral. What I came up with was: 2...
  33. D

    Minimum distance between a point and a bounded line in 3D

    I have a point in 3D specified by its coordinates (x0, y0, z0) I have a line in 3D specified and bounded by its end points (x1, y1, z1) and (x2, y2, z2) How do I calculate the minimum distance between the point and the line, keeping in mind that it may not be the perpendicular distance...
  34. S

    2D Perspective xform using CSS 3D matrix?

    Hi, I have used Mathematica to determine a 3x3 perspective transformation from one 2D image to another. Let's say that Mathematica gave me the following 3x3 matrix: a b c d e f g h 1 Now, moving outside of Mathematica, I'm trying to use that perspective xform it gave me in...
  35. R

    MATLAB Merge 3 FFT Spectrum Graphs in MATLAB - Step-by-Step Guide

    How can we merge 3 FFT spectrum graphs in one as shown in the picture? AND THANK YOU I have written the codes for the 3 spectrums but need to join them as shown.
  36. R

    3D Distance Formula Calculator Program

    Hello. I have the distance formula programmed into my calculator and I searched for a distance formula that includes the z-axis but I couldn't find any. Does anyone know how to make such a program for the TI-84? Thank you.
  37. T

    MATLAB Matlab 3D plot using arrays in if/else

    Dear fellows, I am trying to plot a 3D graph, determining the x and y values using an array and the z values using if/else. This is the code I am playing with but I can't get it to work: xmin=-1000; xmax=1000; division=1.0; num=((xmax-xmin)/division)+1; for i=1:(num/2)...
  38. C

    Angular velocity of a 3D rigid body with Eulerian Angles

    Say I have an odd shaped rigid body in pure rotation. I fix an orthogonal x-y-z coordinate system to the body, and coincide the origin of this coordinate system to the origin of my global coordinate system X-Y-Z. I have 3 Eulerian angles (as functions of time) which I can use to describe the...
  39. King Tony

    PDE Separating Variables for 3d spherical wave equation

    Homework Statement Just need someone else to double check more work. I just want to know if I'm separating these variables correctly. Homework Equations \frac{\partial^2u}{\partial t^2} = c^2\nabla^2u The Attempt at a Solution Allow u(\rho, \theta, \phi, t) = T(t)\omega(\rho...
  40. C

    Gravity waves propagation in 3D Space

    Im a visual person, and I have a strong interest in Physics for some reason too. Im trying to picture how Gravitational waves would look not in Spacetime but in normal space. Are they like concentric rings surrounding the source? And how do they differ in shape when there are 2, 3 or more...
  41. M

    3D Mohr's circle conceptual question

    This is more of a general conceptual question than a specific homework problem. I know how to do these problems, but I'm not understanding part of them. So, with a given stress element, I first look at one specific face, and plot a two-dimensional Mohr's circle. Then, I find the center...
  42. C

    3D Plotting for Mac: Find the Best Option

    Can anyone help me to find a good 3D plotter for Mac?? I am searching it because I want to plot data that I got from a simulation that I did.
  43. N

    Ordering Line Segments to form a 2D Polygon after slicing a 3D Tri Map

    I have a 3D shape described by a triangulation map i.e. a map between the vertices to the faces of the shape which are all triangles. I then sliced the shape by a plane and computed the intersections of the plane and the triangle faces. Each triangle face that intersects the plane, will have...
  44. P

    Mean, simplified from 3D to 1D

    Hi, There are three variables ax, ay and az, my question is: How to simplify the mean value <(ax^2+ay^2+az^2)^(1/2)> to <|ax|> ? What assumptions are required during the simplification? The statistical property of ax, ay and az is <ax^2>=<ay^2>=<az^2>. The assumption of the propability...
  45. Q

    3D Rectangular Scattering Potential

    Homework Statement There is a constant potential, V0, in the region -a<x<a, -a<y<a, -b<z<b, and V=0 otherwise. Particles of mass m are incident on the scatterer with wave vector k in the x direction with a flux at the origin of one particle per second per cm^2. There is a detector with...
  46. L

    How Do You Solve a 3D Truss Problem in Statics?

    Homework Statement I am trying to analyse a 3D truss problem (attached). The idea is that when you pull with a force F in the direction of the arrows, the pin in the middle will be pressed downwards, decreasing the length of p2. In general the overall structure will be consistent of a series...
  47. A

    What is the best 3d CAD software?

    Currently I'm teaching myself Autodesk Inventor and it seems to be going pretty well. I was wondering though, in the job market what program is most used? Also what program is the most powerful in the design process? I guess what I'm really looking for is the program that would most benefit me...
  48. A

    Calculating Inertia on Viviani's Curve

    I need to calculate inertia for a mass moving on viviani's curve. Anyone here care do guide me on how to do this ?
  49. M

    MATLAB MATLAB 3D Plot assistance needed

    Hi guys! Kinda stuck here.. I'm trying to plot the temporal temperature distribution across a metal rod of length 1 meter. The rod is heated at one end and the temperature is measured every 5 cm along the meter rod every 10 minutes for an hour. Basically I have 6 text files, each...
  50. khurram usman

    How to Calculate the Energy of an Electron in the 3d Orbital of an Oxygen Atom?

    if i am to calculate the energy of an electron in the 3d orbital of oxygen atom...how i am supposed to consider the electronic configuration? i mean i can easily do so for 2p or 2s using slaters rule...because the electrons are present in those orbitals but for the 3d case where should i...
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