3d Definition and 1000 Threads

  1. E

    Here is a 3D model of 13th century French cathedral that I made

    It's the Saint-Etienne cathedral in Auxerre France. Created using Blender 2.92, rendered in cycles render.
  2. S

    I Why is this 3D operator with degeneracies only giving me 2 eigenstates

    The matrix representation of a certain operator in a certain basis is $$\begin{bmatrix} 1 & 0 & 0 \\0 & 0 & -i \\ 0 & i & 0 \end{bmatrix} .$$ The eigenvalue problem leads to this equation $$0=det\begin{bmatrix} 1-\lambda & 0 & 0 \\0 & -\lambda & -i \\ 0 & i & -\lambda \end{bmatrix}...
  3. R

    Weakly interacting Bosons in a 3D harmonic oscillator

    1. Since N is large, ignore the kinetic energy term. ##[-\mu + V(r) + U|\Psi (r)|^2]\Psi (r) = 0## 2. Solve for the density ##|\Psi (r)|^2## ##|\Psi (r)|^2 = \frac{\mu - V(r)}{U}## 3. Integrate density times volume to get number of bosons ##\int|\Psi (r)|^2 d\tau = \int \frac{\mu -...
  4. koustav

    Find Ground State Energy of 3D Harmonic Oscillator

    Summary:: I am trying to find the exact ground state energy of the hamiltonian.kindly help me with this
  5. A

    3D object parallel projection, filtering of facets

    I'm sorry if the wording is a bit clunky, but this is not a common topic for me. Say you have some 3D object consisting of vertices and facets. There are many tools that can visualize this and they only show its projection on 2D, i.e. on your screen. I presume that you would filter the faces...
  6. NatanijelVasic

    3D Cinema Glasses: An Unsolved Personal Experience

    Many years ago I went to the cinema to watch Avatar in 3D, and was provided with polarising 3D glasses at the venue. I can't remember if it was my first 3D film that involved polarising projection technology, but it was certainly one of my first. In any case, the 3D effect worked and I got...
  7. E

    3D model I made of the Fukushima Daiichi control room

    I spent the past week and a half making this 3D model using a program called Blender 3D, or the Fukushima Daiichi nuclear power plant control room.
  8. kolleamm

    3d printing materials with different melting points?

    A 3d printer that could print metal and other materials would revolutionize everything. The only problem is that metals have a really high melting point, so if you try to get a metal hot enough to bind to the other metals in its vicinity it would probably destroy the bonds of the neighboring...
  9. D

    Tetrahedron Simplex Shape Functions in FEA

    Hi, 2 part question trying to get tetrahedron Finite Element shape functions working: 1) How do I properly setup the shape coefficient matrix and 2) How do I build the coefficient quantities in the shape functions properly? ANY tips or corrections may unblock me and would be of much value...
  10. E

    This is a 3D model I made of the Edmund Fitzgerald great lakes ship

    These are images of a 3D model I made of the legendary Edmund Fitzgerald, a great lakes bulk carrier ship, which famously sank in lake superior in 1975.
  11. E

    Have you seen this stunning 3D model of a VVER reactor made with Blender 3D?

    Made using Blender 3D, version 2.9, rendered in eevee. https://www.artstation.com/artwork/oAmVDw
  12. F

    Why are new dimensions added to the left in numpy arrays?

    Hello, I am clear on 1D and 2D Numpy arrays, how to create them and address them). 1D array: single list 2D array: list containing multiple lists as elements 3D array: list containing lists which contain lists as elements Array elements can be address using indices as a[], a[][], a[][][]...
  13. Citronnier

    Film Advance system research for DIY Camera

    Dear All, I'm a french professional photographer working on Still Life and Architecture. As a long time and personnal project I'm working on a 3D printed/Laser cut analog camera that will shoot 6x4.5 frames. In the end it will be some kind of rangefinder with integrated electronic light...
  14. T

    What machines are used to manufacture extruder screws for 3D printers?

    Currently I am working on an assignment about making an extruder screw for screw based 3D printer. I am confused that actually what kind of machines those manufactures out there using to manufacture this kind of extruder screws ?
  15. jk22

    Can holographic displays be adapted for use in a 3D display with lasers?

    Is the following realizable : We suppose two non visible lasers whose direction and phase could be changed very quickly. The energy of just one laser would correspond to no possible transition in the atomic spectra of the molecules present in the atmosphere of the room. However if both...
  16. SamRoss

    B Do any 3D Venn diagrams exist that have no 2D analogues?

    If we were to use three-dimensional spheres to represent sets, could a 3D Venn diagram be constructed that could not be drawn as a normal 2D Venn diagram without changing the relationships between the sets?
  17. I

    A What is the packet speed in the discrete case?

    I've been struggling with the problem below for some time. It is not a homework. A simple bubble S is a spherical surface that expands with constant speed c. A vector bubble V also expands with the same constant speed c. There is a 3d vector associated with a V. If two S bubbles touch, they...
  18. Janus

    The difference a new computer makes for 3D rendering

    Just recently, I finally upgraded my 7+ year old computer. I was able to find a good deal on a HP Omen, with a Geforce RTX 2060 graphics card. So, not only was I able to upload the latest build of Blender, but I was able to go back and tweak some renders I had done with the old computer. For...
  19. S

    3D Volumetric Strain and Volume Change

    Summary:: Can anyone help me with this 3d Volumetric Strain and Volume Change. The is question is attached as a document below with the question and my attempt at the answer All questions and attempted answers are in the attached file below
  20. E

    3D Printer Stepper Motor Torque Requirements Using Gear Reduction

    I hope to explore mechanical engineering one day so I can answer these kinds of questions on my own, but until then, I appeal to anyone that knows how to do this to help me. I am building a core xy 3D Printer and I want to use a belt driven Z axis. I will have 3 or 4 stepper motors to drive...
  21. B

    Solving 1D First Order Equations for 3D Mass Positions and Velocities

    Okay so I need to find 12 one dimensional first order equations that describe the position and velocity of both masses in 3 dimensions. The equations for the second body will be easy once I figure out how to do the first body, so I'll ignore that for now. For the first equation, I can rearrange...
  22. E

    Here is a 3D model I made of the Mir space station

    This is a 3D model I made of the Mir space station.
  23. Martian2020

    B Visualize 2D Intrinsic Curvature of Spacetime (1s+1t) in 3D

    Via web search found https://www.physicsforums.com/threads/what-dimension-does-space-time-curve-in.852103/ Read it and watched two videos mentioned: I understand we cannot perceive 5D ;-), so extrinsic visualization of maximum of 2D intrinsic curvature is possible. So time+1d space is all we...
  24. A

    I Electrodynamics of Dielectrics: 4D to 3D

    Hi, so the four-dimensional generalization of $$\vec{B}=\mu\vec{H}$$ is $$F_{\lambda \mu}u_{\nu} + F_{\mu \nu}u_{\lambda} + F_{\nu \lambda}u_{\mu} = \mu (H_{\lambda \mu}u_{\nu} + H_{\mu \nu}u_{\lambda} + H_{\nu \lambda}u_{\mu})$$ From these four-tensors and four-vector I should be able to...
  25. dasil12a

    3D Solid State Simulation Software

    How did you find PF?: Google I am studying the mechanical/electrical nature that govern certain nano-fabricated crystalline structures. Can someone with experience please recommend a 3d Solid State Simulation software that will allow me perform the following: Allows individual 3D placement...
  26. I

    I Quantum Mechanics Wave Function in 3D

    I was wondering if it's possible to plot a wave function that is a function of 3 coordinates, such as (x, y, z). The text my class uses calls this Quantum Mechanics in 3 dimensions, but wouldn't this technically by four dimensions?
  27. F

    A How Are 2D and 3D Cross-Correlations Implemented in Large-Scale Surveys?

    In the context of forecast for large survey, I have to make cross-correlations between 2D (with angular coordinates of Lagrange transformation for GC photometric and Weak Lensing) and 3D (Fourier transform with radial coordinates for GC spectroscopic). For the moment, only cross-correlation...
  28. L

    I Intersection of a 4D line and a 3D polyhedron in 4D

    Is the intersection of a 4D line segment and a 3D polyhedron in 4D a point in 4D, if they at all intersect? Intuitively, it looks like so. But I am not sure about it and how to prove it.
  29. K

    I How can I rotate a vector in 3D to match another vector's rotation?

    Suppose I have a three dimensional unit Vector A and two other unit vectors B and C. If B is rotated a certain amount in three dimensions to get vector C, how do I find what the new Vector D would be if I rotated Vector A the same direction by same amount?
  30. B

    2D vs 3D Method of Characteristics for Rocket Nozzle Design

    Hi all, I'm working on programming a simple 2D method of characteristics program to design the nozzle wall contour for a supersonic rocket nozzle. I'm wondering roughly what sort of difference I should expect from a 2D vs 3D method of characteristics program and where I could find a good...
  31. L

    I Exploring the Impossibility of Higher Dimensions: 3D vs. Beyond

    Assuming there are higher spatial dimensions are there things that exist in 3D that actually cannot exist in higher dimensions? Maybe even dimensions?
  32. F

    A Cross correlations with 2 probes: Approximation of a 2D + 3D synthesis

    I am interested, in the context of my work, in the cross correlations between a spectroscopic probe (which gives a 3D distribution of galaxies with redshifts, which is also called spectroscopic Galaxy clustering, GCsp) and a photometric probe (which gives an angular distribution, that is to say...
  33. mcrooster

    How to find Tb and Moments 3D equilibrium of rigid bodies

    The boom is supported by a ball-and-socket joint at AA and a guy wire at BB Hey guys, I am stuck with this question in find the Tension in B and the moments around A. I have done plenty of 2d Tension questions but not a 3D one.
  34. F

    3D printing and G-code files....

    Hello, I am aware that the workflow of 3D printing involves the following steps: 1) Design the part using CAD and saving it as a .stl file. 2) Import the stl file into a slicing software to be converted to a G-code file 3) Load and run the G-code file on the 3D printer It is simple and safe to...
  35. F

    3D Printing and "Watertight" Digital Models

    Hello, I understand that CAD models (stl files) suitable for 3D printing must be "watertight" and not leaky in the polygon mesh. By analogy, if we filled the model with water, the water would not leak...This concept of watertightness means that there are no unintentional holes between the...
  36. John321

    A Relationship between the angular and 3D power spectra

    I have the following equation, $$ C_\ell(z,z') = \int_0^\infty dkk^2 j_\ell(kz)j_\ell(kz')P(k),$$ where $$j_\ell$$ are the spherical Bessel functions. I would like to invert this relation and write P(k) as a function of C_l. I don't know if this is a well known result, but I couldn't find...
  37. kolleamm

    Is it possible to polarize a complex 3d shape?

    I have this idea for LED eyes. Basically its an LED screen behind a half spherical shape. I want the user only to see what's on the display if they are looking directly at it. So for that I would need to polarize the half sphere. The half sphere can be made out of anything, the problem is how do...
  38. S

    B Understanding 3D Temperature Direction Change with 8 Corner Points

    So I have a cube in 3d space and this cube is made out of 8 coordinate points at each corner. Now I have a temperature reading at each point of these corner points. Inside the box I have another point, I want to be able to use the information from the 8 points surrounding the the one middle...
  39. M

    MATLAB Plotting a 3D image from a matrix for a complex domain

    Hi PF! Each element of an ##n\times m## matrix is complex valued. In the following code, I call this "domain". There is also an ##n\times m## matrix that is real valued, below I call this "f". I'd like to plot a 3D image where the ##x-y## plane is the complex plain given by the coordinates...
  40. H

    Troubleshooting 3D Vector Work: Solving Angle and Displacement Confusion

    I'm having trouble finding the angle and displacement
  41. Ishika_96_sparkles

    Mathematica How to Enhance 3D Parametric Plots in Mathematica?

    This is the code line that i used to generate the following graphs ParametricPlot3D[{{1 + Cos[t], Sin[t], 2*Sin[t/2]}, {2 *Cos[t]*Sin[\[Phi]], 2*Sin[t]*Sin[\[Phi]], 2*Cos[\[Phi]]}}, {t, 0, 2 \[Pi]}, {\[Phi], 0, \[Pi]/2}, PlotStyle -> {Directive[Green, Thickness[0.025]], Yellow}...
  42. Islam Hassan

    I Mass & Radiation 3D Distribution in the Universe

    What percentage of the universe’s A) total mass —including dark matter— and B) radiation energy is estimated to reside in: Inter-galactic space covering i) inter-galactic medium and ii) distinct inter-galactic astronomical objects; and Galaxies covering iii) inter-stellar gas clouds, iv) stars...
  43. E

    3D model of an RBMK reactor refueling machine

    I made this 3D model of the RBMK-1000 nuclear reactor central hall about 3 years ago. But I did not model the fuel handling machine. Recently I decided to complete it by modeling the fuel handling machine.
  44. P

    Confirming Green's function for homogeneous Helmholtz equation (3D)

    Plugging in the supposed ##G## into the delta function equation ##\nabla^2 G = -\frac{1}{4 \pi} \frac{1}{r^2} \frac{\partial}{\partial r} \left(\frac{r^2 \left(ikr e^{ikr} - e^{ikr} \right)}{r^2} \right)## ##= -\frac{1}{4 \pi} \frac{1}{r^2} \left[ike^{ikr} - rk^2 e^{ikr} - ike^{ikr} \right]##...
  45. S

    I Help with a 3D Line Integral Problem (segmented line)

    Hi all, I'm finding it difficult to start this line integral problem. I have watched a lot of videos regarding line integrals but none have 3 line segments in 3D. If someone can please point me in the right direction, it would help a lot. I've put down the following in my workings: C1...
  46. BoltE

    How do you invert a 3D matrix? (Tensor inversion)

    I would like to solve a system of systems of equations Ax=b where A is an n x m x p tensor (3D) matrix, x is a vector (n x 1), and b is a matrix (n x p). I haven't been able to find a clear walk-through of inverting a tensor like how one would invert a regular matrix to solve a system of linear...
  47. Boltzman Oscillation

    Help designing a self guided automatic 3D printer

    All in the summary, can't copy paste on phone :(
  48. 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...
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