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. L

    MHB Rate of Change of Airplanes in 3D

    One plane is flying due east straight and level at 30000 feet and at 420 mi/h. A second plane flies due north at 40560 feet and at 480 mi/h. The second plane crosses above the flight path of the first plane 2 minutes after the first plane passes that point. How fast were they approaching each...
  2. P

    How to simulate a coil in Ansoft Maxwell 3d?

    Hello, I want to simulate a coil of a transformer in Maxwell (3D), but my problem is: the coil design is not a closed path. Imagine that you draw a ring and then you cut part of it. You get something like a "letter C". In these two terminals I`m going to put an excitation (100A, for...
  3. U

    3D Harmonic Oscillator Circular Orbit

    Homework Statement I found this in Binney's text, pg 154 where he described the radial probability density ##P_{(r)} \propto r^2 u_L## Homework Equations The Attempt at a Solution Isn't the radial probability density simply the square of the normalized wavefunction...
  4. 6

    Is the fabric of space time 2d or 3d

    Well when I watch movies I see space time as 2d. But how do we see the space time from Earth to a region lower than earth.
  5. J

    Finding moments of a 3D model.

    Homework Statement (See pic attachment)Homework Equations Moment/Torque = Force * d (Force arm)The Attempt at a Solution I have so far Mx = Fz * ya My = Fx * za Mz = -Fx * ya How I got these answers is by looking at the cube from the component's axis and whether or not it produces a torque...
  6. F

    3D Moment with force and couple

    Homework Statement The special-purpoise milling cutter is subjected to the force of 1040 N and a couple of 211 N·m as shown. Determine the moment of this system about point O. (Let's laugh at the text's typo)Homework Equations Mo = R x F + (Couple)The Attempt at a Solution I'm having a little...
  7. A

    Can I get Bandgap of 3D material with 1D Hamiltonian

    Hi All, Greetings! I have a 3d material and I use result from first principal for getting the potential (U(x,y,z)). I then find average U(x) from U(x,y,z). Now if I write one dimensional Hamiltonian in X direction and use this value of U(x), can I get bandgap of the original 3d material (I...
  8. T

    What are the possible values for the coordinate angles in 3-D space?

    [b]1. Homework Statement [/ In 3-D coordinate space, any two of the coordinate angles must … Select one: a. sum to less than 1 b. be greater than 90° but less than 180° c. each be greater than 45° d. sum to greater than 90° (if they are both less than 90°). e. have cosines less than...
  9. T

    Are 3D coordinate angles restricted to certain values?

    Homework Statement In 3d coordinate space any two of the coordinate angles must A. Sum to less than one B. Be greater than ninety but less than one eighty. C. Each be greater than forty five degrees D. Sum to greater than 90 ( if they are both less than 90) E. Have cosines less than...
  10. T

    Representing Vectors in 3D Space

    Homework Statement In 3D space a full vector can be represented I. All the following except A. In Cartesian vector form B.As a magnitude times a unit vector C. As a Cartesian vector times a unit vector D. As magnitude with coordinate angles Homework Equations The Attempt at a...
  11. J

    ANSYS Workbench - 3D rope on a pulley with friction

    Hello everyone, First of all, I want to excuse for my not perfect English since it isn't my mother tongue. However, now to my problem, which I'm facing at the moment. As part of my master thesis I have to simulate the application of a fastening device, which I develope during my master...
  12. V

    Boundary conditions for inhomogeneous non-sepearable 3D PDE

    Hello, I am looking to solve the 3D equation in spherical coordinates \nabla \cdot \vec{J} = 0 using the Ohm's law \vec{J} = \sigma \cdot (\vec{E} + \vec{U} \times \vec{B}) where \sigma is a given 3x3 nonsymmetric conductivity matrix and U,B are given vector fields. I desire the...
  13. P

    Anthropomorphic Dummy Movements in 3D Space

    Hi Guys, I have been assigned a task to automate the movement of a Human Body (We are using a Human Dummy) using Python Scripting. The Input for this tasks are the Joint Angles (Perhaps similar to a Robotic Joint). We use the terminology of R,S and T to represent Rotation around the Three...
  14. E

    MATLAB MATLAB 3D Plotting: Tutorial & Help

    Hi Friends, The code below is for 2D ploting in Matlab, I want to change it in 3D, please if anyone know how to do this.let me know thanks in advancefigure(1); popcosts=[pop.Cost]; repcosts=[rep.Cost]; plot(popcosts(1,:),popcosts(2,:),'b.'); hold on; plot(repcosts(1,:),repcosts(2,:),'r*'); hold...
  15. S

    MATLAB How to plot 3d graphs from multiple .dat files in matlab?

    In my project I basically need to plot 3D color coded surface graphs using MATLAB taking input from multiple .dat files (i have 1000 .dat files). In each file I have parameters x and y, and when I take multiple files, each having a different value of z, I can finally plot a graph. so does anyone...
  16. D

    Is it possible to specify a 3d surface in 4d space with just one vector?

    I hope this is the right forum... In 3d space, a 2d plane can be specified by it's normal vector. In 4d space, is there a 3d plane, and will these planes be specifiable by a single vector?
  17. cactusblanket

    Acceleration of a Charged Particle in 3D Vector Notation

    Homework Statement Hi there! Here is a problem from our 1st year course. We have covered the basics on charges and Coulomb's Law. However our prof said he designed the following question to be "deliberately obscure"! Two charges of 4.00μC are fixed in space, Q1 at (0,0,0) and Q2 at...
  18. M

    C# 3D N-Body Problem (Solar System) C#

    Hey there, first time posting, I have casually browsed this forum for a while. Anyway on to the question, I am trying to solve in the best way possible the N-Body problem, I am at a complete loss, I have no idea what I can do, I have tried figuring out my self different integrators such as...
  19. S

    Vector field flow over surface in 3D

    Homework Statement Calculate the flow of ##\vec{F}=(y^2,x^2,x^2y^2)## over surface ##S## defined as ##x^2+y^2+z^2=R^2## for ##z \geq 0## with normal pointed away from the origin.Homework Equations The Attempt at a Solution The easiest was is probably with Gaussian law. I would be really happy...
  20. C

    Minimum distance between a disk in 3d space and a point above the disk

    Hi all, How can I calculate the minimum distance between the perimeter of a disk in 3d space and a point above the disk? (the point can be inside or outside the area above the disk) I've been trying to work this out for a while, but I'm getting no where. For example, a point at (1,1,1)...
  21. applestrudle

    Length of a 3D parametric function

    Homework Statement find the length of a circular helix expressed in parametric form x= cos(t), y=sin(t) and z = t from t = 0 to t =2pi Homework Equations L = integrate ds (ds)^2 = (dx)^2+(dy)^2+(dz)^2 The Attempt at a Solution I got to ds = (1 + (dt)^2)^0.5 but I can't...
  22. B

    MHB How to calculate center coordinates of two reverse arcs in 3D space

    Hi, Given 3D points P1(200,60,140), P2(300,120,110), P3(3,0,-1), P4(-100,0,-1) and the radius of arc C1MP3 is equal to radius of arc C2MP1. How do I calculate coordinates x, y, z of points C1 and C2? Points C1 and C2 are centers of two reverse arcs which are tangent to each other at point...
  23. B

    How to calculate center coordinates of two reverse arcs in 3D space

    Hi, Given 3D points P1(200,60,140), P2(300,120,110), P3(3,0,-1), P4(-100,0,-1) and the radius of arc C1MP3 is equal to radius of arc C2MP1. How do I calculate coordinates x, y, z of points C1 and C2? See this image. Points C1 and C2 are centers of two reverse arcs which are tangent to...
  24. E

    MATLAB Graphing 3D Z-Transform in MATLAB

    Does anyone know how I might go about graphing the Z-Transform in 3D? It want it to look something like the picture below.
  25. T

    Calculating a theta using dot product in 3D coordinate

    I'm so confused about finding an angle, theta in this illustration. With having three coordinate information, how can I calculate the theta using dot product? I would easily find the angle by using trigonometric formula if I ignore the z-axis. But I want to solve this problem with...
  26. Raerin

    MHB Solve 3D Vector Equation: x-int=3, z-int=-1; (x,y,z)=(p1,p2,p3)+t(d1,d2,d3)

    Question: Write a vector equation which has an x-intercept of 3 and a z-intercept of -1 I want it in the form of (x,y,z) = (p1, p2, p3) + t(d1, d2, d3) I don't have a clear idea on how to solve it.
  27. T

    Maximizing Energy Conservation in Particle Motion on a Helix Wire

    Homework Statement A particle P is free to slide on a smooth wire which has the form of a helix, with a position vector given by: r((t)) = a cosθ(t)i + a sinθ(t)j + bθ(t)k The particle is released from rest at the point (a, 0, 2∏b). Using energy conservation for conservative...
  28. D

    Degenerate Perturbation Theory (Particle in 3D box)

    Homework Statement Consider a particle confined in a cubical box with the sides of length L each. Obtain the general solution to the eigenvalues and the corresponding eigenfunctions. Compute the degeneracy of the first excited state. A perturbation is applied having the form H' = V from 0...
  29. T

    4th Vertex in a 3D Parallelogram

    Homework Statement Let P, Q, and R be the vertices of a parallelogram with adjacent sides PQ and PR. Find the other vector S. P (2, 0 ,-1), Q (-2, 4, 1), R (3, -1, 0) Homework Equations PR = QS PQ = RS The Attempt at a Solution I took the two equations and solved both of them...
  30. Vanrichten

    MHB Multiple Integral and Optimization in 3D

    In this problem I have drawn out the region specified and noticed two sets of parallel lines indicating to me that a change of variable(u and v) are able to be used to solve this integral. I decided that u=y-x and v = -2x-y then solving for x and y I obtain x= (u-v)/3 and y = (4u-v)/3 From...
  31. A

    Question about finding quantom numbers N_(n) for Schrodinger Eqn in 3D

    I'm using the Modern Physics by Tipler (6th edition) book. In sec 7.1 it talks about the first excited state being either E_(112 ) E_(121 ) E_(112). My question is what is the process of finding the n_(1),n_(2),n_(3) quantum numbers ? How i understand you pick random values and from their find...
  32. M

    Engineering Statics 3D equilibrium (sleeves and ball joints)

    Homework Statement Ends A and B of the 5-kg rigid bar are attached by lightweight collars that may slide over the smooth fixed rods shown in the figure. The center of mass of the bar is at its midpoint. The length of the bar is 1.5 m. Determine the horizontal force F applied to...
  33. D

    Why this solution to the 3D periodic Navier-Stokes?

    Who can provide a physical understanding to this solution to the 3D periodic Navier-Stokes equation: http://purvanced.wordpress.com?
  34. S

    3D Vectors and resultant force

    Homework Statement The vertices of a quadrilateral are A(1,2,-1) B(-3,2,-3) C(4,1,-4) and D(2,-1,3). At A forces of magnitude 4, 5 and 4 are Newtons act along AB, AC, and AD respectively. Find the resultant force. Looking for more of a hint than an answer. Any help would be...
  35. A

    Difference between 1D, 2D and 3D Flow

    Hey guys, I'm new to this forum and was hoping to get a clear answer regarding the difference between 1D, 2D and 3D flows in hydraulics (ex. 2D Numerical Model...) ? Thanks a bunch! -A.
  36. E

    Recommended software for converting 2D images to 3D CAD model.

    Hello, Does anybody know/had experience with software that can turn 2D images to 3D models in CAD program, preferably in an offline environment (not on cloud)? The resulting model has to be accurate enough for aerospace engineering purposes. from looking online, I really didn't find...
  37. R

    3d printing with Polylactic acid, adhesion to print bed

    I recently built a 3d printer that extrudes PLA or Polylactic acid for the material. When printing on a glass bed the pla drags behind the extruder because it won't stick to the glass. On the other hand printing on a sheet of acrylic the PLA sticks so well that it is difficult to remove after...
  38. A

    Simple question about parametric equations of a plane in 3D

    I'm quite rusty in Linear Algebra. If you have a plane in 3D with the equation ##z=2##, what does ##x## and ##y## equal? Does ##x=t## and ##y=t##? Because if I graph that in Wolfram Alpha, I don't get a horizontal plane in 3D at ##z=2##...
  39. R

    3d printing with Polylactic acid, adhesion to print bed

    Polylactic acid (PLA) is a very popular raw material used for plastic extrusion 3d printers. Myself and many others in the 3d printing community have have experienced difficulty getting the the first layer to stick to the bed. I have tried a couple things so far 1) Heated smooth glass bed...
  40. 0

    Center (in y direction) of Mass of 3D pyramid

    Homework Statement A monument is made from stone blocks of density 3800kg/m^3. The monument is 15.7m high, 64.8m wide at the base, and 3.6m thick from front th back. How much work was required to build the monument? (Hint: find ycm). Homework Equations ycm = (1/M) * ∫ydm, M = mass total...
  41. B

    3D Printing Technology/Additive Manufacturing

    Hello Everyone, I am currently in my last year of studies, working towards a BSc in Mechanical Engineering. Anyway, I recently came across a very interesting article about the recent advancements in industrial 3D printing. The article discusses 'AMAZE', a project launched by the European...
  42. X

    Seriously stuck 3D Quantum Harmonic Oscillator

    Homework Statement The question is from Sakurai 2nd edition, problem 3.21. (See attachments) ******* EDIT: Oops! Forgot to attach file! It should be there now.. *******The Attempt at a Solution Part a, I feel like I can do without too much of a problem, just re-write L as L=xp and then...
  43. S

    3D Rotations using complex numbers

    I was thinking that if you could use quaternions to rotate an object using quaternion algebra that there might be a way to rotate an object using complex numbers in some fashion. I was looking at quaternion rotation of a vector and the amount of operations seemed to be a lot. Of course it levels...
  44. T

    3D Scanner using static electric fields

    Greetings PFers, Can someone help explain to me the difficulties of designing a device which utilizes static electric fields to map an objects’ internals and externals? My understanding is that as a electric field propagates through matter, it encounters absorption. I envision a device...
  45. A

    How Do You Calculate the Memory Address of Temp[40,30,20] in a 3D Array?

    Homework Statement The problem is finding the memory location of a three-dimentional array Temp. Each index of temp goes from 1 to 100 and each element stores 4 bytes. The array is setup such that the last index varies fastest, aka: Temp[1,1,1], Temp[1,1,2], ... Temp[1,1,100]...
  46. S

    Ansys maxwell 3d material library

    hi everybody. i just wonder. can we add new material library in ansys maxwell 3d(v.16) manually. especially magnets?
  47. U

    Finding Reaction Forces in 3D Equilibrium: Solving a Tricky Bent Rod Problem

    Homework Statement in the attached picture are all the information needed to solve the problem. The bent rod of a negligible weight is supported by a ball and a socket joint at A and a single journal bearing at B. End of D of the rod rests against a friction-less vertical surface. find...
  48. carllacan

    Finding normal modes of a 3D object

    Hi. I'd like to find the normal modes / harmonics, displayed in a dB - Hz graph, of a given 3D object, namely a wind instrument shaped like a hyperbolic con with holes. I'm trying to perform simulations on Comsol Multyphysics, but I don't know how to do it. Is Comsol the best suited software...
  49. H

    Why Do 4s Orbitals Fill Before 3d as Atomic Number Increases?

    Homework Statement Explain why, as the atomic number increases, the 4s electronic states fill before the 3d states. The fact that they fill first means they are lower energy. You must explain why they are lower energy. Homework Equations The Attempt at a Solution First, I'm aware...
  50. S

    Solve 3D Statics Problem: Find Direction Angles of Vector Force

    Hi again. Can somebody guide me in find the direction angles of the vector force given below?
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