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. B

    MHB Finding exact 3d coordinates in a falling pipe system with corners

    Hi All. I'm new here so I hope you will bear with me and please tell me if this is out of context or in the wrong part of the forum. I am trying to programm a falling pipe system with corners in ArchiCAD (GDL). I have been programming in different languages for a while now, but new to 3D vector...
  2. E

    I Linear Algebra and Identity Operator Generalized to 3D

    I'm just getting into 3D quantum mechanics in my class, as in the hydrogen atom, particle in a box etc. But we have already been thoroughly acquainted with 1D systems, spin-1/2, dirac notation, etc. I am trying to understand some of the subtleties of moving to 3D. In particular, for any...
  3. Robin04

    Solving 3D Vector Equation for ##\vec{y}##

    Homework Statement Solve the following vector equation for ##\vec{y}##. ##\vec{a}##, and ##\vec{b}## are linearly independent vectors of the three dimensional space. ##\vec{a} \times (8\vec{y}+\vec{b}) = \vec{b}\times(-5\vec{y}+\vec{a})## Homework EquationsThe Attempt at a Solution First I...
  4. Avatrin

    3D file manipulation resources

    Hi I am trying to learn how to manipulate 3D files like obj or stl using programming (I primarily use Python, but also know Javascript). Which resources can I use to learn this?
  5. A

    3D backprojection (potential project)

    I just thought about whether it is possible, or already exists, a method to construct a 3D optical scene using the method of backprojection. First, I will capture the scene (say a castle) from different views using HD camera. Then using one of the app to stitch the 2D images into a cloud of...
  6. L

    Potential due to Uniform Charge Distribution (3d)

    Homework Statement Homework Equations dV= integral(kdQ/dR) The Attempt at a Solution So, I'm familiar with these type of problems but in 2D (like a line of uniform charge). When the y,z component is added, I'm kinda lost. i know dQ = p*dV= p*dx*dy*dz. (atleast i think it is). also the dR =...
  7. A

    A Could the 3D percolation model explain Regge-Trajectories?

    Regge-theory succesfully explains the latest LHC ##pp## elastic scattering experimental results and total cross-sections: https://arxiv.org/pdf/1711.03288 https://arxiv.org/abs/1808.08580 Three different Regge-trajectories are needed: one Reggeon, one (soft) Pomeron and one Odderon. The...
  8. Bayu

    Simple lever for a 3d printed gate

    Homework Statement Hi I am new here!,i want to thanks for all great information, Today i try to make a lever works with my hot wheels start gate,it should be work like gate,when i push the lever down,the gate will going down but i can't make the gate open at the same time between the first...
  9. YoungPhysicist

    Which function drawer is this one?

    Have anybody seen a 3D function drawer like this one?(4:12) Since I don’t know what these 3D drawers are really called,I can’t find any.
  10. kenneththo85431

    Describing Electronic orbit in 3D space using A matrix.

    I've plotted out the trajectory of an imaginary electron in 3D; next I represent it's points with the matrix A(x1 y1 z1) "throughout it's orbit": ( -1/2 -1 1 ( -2 -1.5 2 (-1/2 2 3...
  11. R

    B Is the Universe a 3D Cut of a 4D object?

    I have just simple Knowledge, but recently a question came To my mind. An Entity Living in 2d Space cannot Directly Observe a sphere, but rather a Circle Changing its Size when a sphere is traversing trough the observable 2d plane. Similar, a 4d sphere would Appear To us as 3d sphere Changing...
  12. R

    I 3D coordinates vector calculation

    How do I calculate the resultant of three component vectors set mutually at 60 degrees to each other (not in the same plane)?
  13. M

    Mathematica 3D parametric vector plot question

    Hi PF! Given a vector field ##\vec f## in spherical coordinates as a function of a single parameter ##s##, shown here as $$\vec f(s) = f_r(s) \hat r + f_\theta(s) \hat \theta + f_\phi(s) \hat\phi$$ where here subscripts do not denote partial derivatives, but instead are used to define...
  14. M

    I Understanding Divergence of Vector Function F in 3D Space

    For the vector valud function F in the image, the three components of the output vector at a point are functions of (x,y,z)the three coordinates of the point.But while calculating divergence, why is the rate of change of x component of the output along x direction alone is accounted(similarly...
  15. Z

    B Is our 3D universe a shadow of a 4D Universe?

    Is it possible that our 3D universe is just a shadow in 3D space of 4D or higher dimensional reality? And we are limited in our perception of it by our 3-dimensionality. In other words like Flatlanders would just see s square of a cube sitting on the plane or passing through the plane...
  16. bob012345

    I How to measure the surface area of an arbitrary 3D object

    I'm looking for an easy way to get the surface area of an arbitrary shaped 3D object. Getting the volume is easy by water displacement. What about area? Any neat tricks? We know different shapes can have the same volume and thus different surface areas so it's not a trivial problem. The purpose...
  17. A

    Fortran Rotation of the coordinates of a 3D function

    Hello, I come across a problem in programming and I do not find a lot of help on the internet, so I hope I can find an answer here. I have a 3D array representing a function, say f(i,j,k) and a basis function u(i,j,k). I would like to perform a general rotation of the basis function u so that I...
  18. G

    Fortran Best 3D Animation Software for Numerical Simulation Data

    hello everyone, I`m trying to make 3d animation from numerical simulation data. Can someone recommend good software for me Thanks in advance
  19. NatFex

    I Rotation of a point in R3 about the y-axis

    Hello, I'm having a visualisation problem. I have a point in R3 that I want to rotate about the ##y##-axis anticlockwise (assuming a right-handed cartesian coordinate system.) I know that the change to the point's ##x## and ##z## coordinates can be described as follows: $$z =...
  20. corpsinhere

    I F(x, y) describing a distorted 3D Gaussian bell

    I am new to these forums - if I have posted in the wrong place please let me know. Standard 3D Gaussian bell: z = e^-(x^2) * e^-(y^2) From along the z-axis this looks "round". I would like a generalized f(x, y) which would look egg-shaped from above - possibly quite distorted.. I thought at...
  21. R

    Understanding Grids and Units in Computer Graphics and Physics Simulations

    Hello, I am having trouble comprehending how grids are made and defined in computers. What is the unit that they use and how is it defined ? I know that softwares use standardized units of measure (measurement) such as centimetre. Basically, how is a 3-Dimensional Space created in computers...
  22. Telemachus

    Correct numerical modeling of the 3D Dirac Delta function

    Hi. I was trying to test a code for the diffusion equation, using the analytical solution for infinite media, with a Dirac delta source term: ##q(\mathbf{r},t)=\delta (\mathbf{r}) \delta (t)##. The code is not giving the analytical solution, and there might be several reasons why this is so...
  23. S

    Stress intensity factor using Ansys APDL for a 3D plate

    I am trying to evaluate SIF for 3D plate using ansys APDL. Please share tutorial/notes if available.
  24. E

    A Surface states of 3D topological insulators

    I have a question (more like a curiosity) related to three-dimensional topological insulators, which support Dirac-like states at their surfaces. From the theory, it is well known that these states are immune to scattering from non-magnetic impurities, i.e. impurities that do not break...
  25. C

    Measure the max angle of a 3D pendulum

    Hi, I need a simple way to measure the maximum angle/vertical displacement of a 3D pendulum (weight hanging from a rope) undergoing random impacts. What will work?
  26. Raghavendar Balaji

    Centre of gravity of a 3D irregular object

    Homework Statement A complex or irregular body with some mass, m. How to determine the 3 co-ordinates of centre of gravity? Homework Equations Moment method with ∑M = 0. The Attempt at a Solution Say I have a gearbox and I need to find the COG. I can mount the gearbox at two longitudinal...
  27. Z

    I Calculating the Ricci tensor on the surface of a 3D sphere

    Hello, I'm trying to calculate Christoffel symbols on 2D surface of 3D sphere, the metric tensor is gij = diag {1/(1 − k*r2), r2}, where k is the curvature. I derived it using the formula for symbols of second kind, but I think I've made mistake somewhere. Then I would like to know which of the...
  28. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    So I printed this antenna with some conductive filament , however the microwaves seems to be going between the layers of the plastic. I surrounded it with Aluminum and still leaking, what can I do to fix it? Can conductive silver paint work?
  29. Telemachus

    Surface plot for a 3D function

    Hi there. I wanted to plot a surface, given implicitly by a function ##f(x,y,z)=c##, with ##c## a constant. My ##f(x,y,z)## is obtained numerically, so I don't know the expression explicitly, I have the values of ##f(x_i,y_j,z_k)## for given integer numbers ##(i,j,k)##, ##i=1,2,3...## same for...
  30. Georges

    Light Reflection: A 3D Designer's Guide

    Light is Reflected from the surface of the object or pass through it(interior) and then the light is reflected ? Sorry for my "noob" question i am a 3D designer just looking for some more knowledge Thanks in advance
  31. BillTre

    Where to Find Affordable Multicolor 3D Printers?

    Several interesting moonscape files can be downloaded from here for 3D printing.
  32. A

    How to make thick line in 3D graphics (webGL)?

    Hi guys, I have a webGL application and my understanding is there is no option or at least the option to make thick lines is not working so I thought I would try to write my own routine. I suppose I could just make a double plot of the data just off-set a bit but I'm not exactly sure how to do...
  33. BillTre

    Nicolas Cage is going to Produce 3D Printers

    They will be of the filament type. Short story here.
  34. S

    3D subsurface laser engraving for translucent minerals?

    3D Subsurface Laser Engraving works for clear glasses like Schott BK7 and B9 Borosilicate Glass. How does one do the same for relatively translucent minerals? I have read research papers on using lasers for tattoo removal and cancer radiation therapy. However, I want to know how the laser's...
  35. lc99

    Understanding 3D Diagrams for Solving Angle Problems

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] I am having trouble visualizing the 30 degree angle? How would i know that it is in between 2 planes and not just 1 plane. I thought it would be in the x/y plane. In cases like this where they should you the angle (arrow) to...
  36. lc99

    Question About a 3D Equilibrium Problem

    Homework Statement Homework EquationsThe Attempt at a Solution rxF I'm trying to find the moment of the 50lb about the x,y,z axes. So, i did the vector from the origin to the top of the larger wheel crossproduct with the force vector of 50. Thus, Vector Origin to Wheel x F vector = (0.2i...
  37. lc99

    Is there a trick to finding these 3D vectors in Cartesian coordinates?

    Homework Statement Homework EquationsThe Attempt at a Solution I am having a bit of trouble visualizing the vectors for these type of problems. The angles they give are very ambiguous and so I am not sure why they are there. For the 45 degree angle, how do i know that this is used for finding...
  38. BillTre

    3D Printing Small Optical Structures

    Specialized 3D printers can now produce small optical elements: Described here. There is also a company that makes light shaping diffusers (for lamps) that control the light by controlling the interference patterns of the light due to microscopic structures on the surface of the diffuser film...
  39. ajbroadbent

    Curved Mesh on Symmetry Boundary in ANSYS Maxwell 3D

    I figured this would be the best place to ask as there doesn't seem to be a FEM/Simulation specific sub-forum here, but I am looking for some help regarding mesh generation in ANSYS Maxwell. I have an array of "micro-needles" that I am applying a voltage to in order to determine the electric...
  40. T

    I Doubling a Cube: Can 3D Geometry Help?

    In plane geometry it is impossible to construct a line equal to the (cube root of 2) times the length of a side of a cube, making it impossible to double a cube with a compass and straight edge. Maybe plane geometry needs one more dimension. What happens if we extend the geometry to 3D(solid...
  41. CivilSigma

    Determining the Centroid of a 3D Section

    Homework Statement [/B] I am having a problem understanding a calculation performed as part of a bigger solution in the design of Slabs. That is, how to determine the centroid of the critical shear section, which consist of 3 planes intersecting to form a 3D model (please see attached...
  42. vibhuav

    B Curvature: Intrinsic vs. Extrinsic - What's the Difference?

    In trying to explain the concept of curved space, many books use the example of the surface of a sphere, which can be considered as a curved 2D space embedded in a higher dimensional, 3D space. I could derive, starting from ##a^2=x^2+y^2+z^2##, that the metric, or the line element, on the...
  43. S

    A Can a 3d holographic universe exist in 3d?

    In a holographic universe model, could our 3D universe be encoded in 3D and still be a holographic universe, instead of 3D information encoded in 2D space? Or is the standard model (non-holographic) of the universe already 3d information encoded into 3d space...
  44. E

    Another work-in-progress 3D model of mine

    Here is another work-in-progress 3D model that I made using blender. It's the lower half of Metal Gear REX from the 1998 video game Metal Gear Solid. https://imgur.com/a/I9zUg I can't wait to post screenshots of the finished version of it!
  45. Janus

    Exploring 3D Reproductions of M.C. Escher Artworks

    I've been a fan of M.C. Escher's art for a long time, and ever since I got into doing 3D rendering, I have done various attempts at doing reproductions of some of his pieces to varying degrees of success. One of the problems I had was doing realistic looking human figures. I recently came...
  46. jan2re

    Principal stresses 3D, solving for direction cosines n1,m1,n1

    Homework Statement -4.882L1+M1+2N1=0 L1-2.882M1=0 2L1-0.882N1=0 L1^2+M1^2+N1^2=1 How to solve for L1 ,M1 and N1 ? 0<L1,M1,N1<1Homework EquationsThe Attempt at a Solution
  47. E

    How Did My First 3D Model Turn Out After Hours of Blender Tutorials?

    This is the very first thing that I made using the 3D modeling program Blender after watching a handful of hours worth of video tutorials on youtube. https://imgur.com/gallery/b8BwM
  48. J

    How to calculate the moment of inertia for complex 3D shapes

    <<<moved from another sub forum, no template>>Hi, I need to calculate the moment of inertia for the component in the attached image so that i can calculate the angular momentum. Is it possible? Overall i am trying to calculate the forces on this lug as it passes around a 3" radius at 2M a...
  49. M

    Automotive How do I solve a 3D problem involving a trailer and wheel sizing using statics?

    Hi all, I have a problem with a 3 wheel trailer and sizing the wheels. Using statics, how would I solve this 3D problem by breaking it down? The trailer is sitting on rectangular section and a plate on top carries an even load of 3500kg (roughly 35kN) If I take a cross section A-A and try and...
  50. D

    I Describing 3d Manifold Objects as a Hypersurface

    Hello, an engineer here that is trying to understand more in topology for some mechanics ideas. It seems to me that any closed (regular) manifold in 3d Euclidean space should be able to be describe uniquely by the combination of the following 1) volume [1 real], 2) centroid [3 reals], and 3)...
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