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. M

    Exploring the Complexity of 3D Space

    hi, why do we need to have additional complexity to 3D space? we know that space holds information. but I'm not aware of any information in the universe which is held by "time dimension".. isn't there only changing space and our brain does the "time job" with memorizing and sorting...
  2. P

    Calculate coordinate in 3D triangle.

    Hi, I'm looking for an efficient way of achieving the following, but having trouble thinking it through: Let's say I have a triangle in three dimensions with vertices A, B and C. Let's say I also have a three dimensional coordinate D. I know the x and z component values for D and I am...
  3. P

    How Do You Calculate Tension in Multiple Supporting Wires?

    Homework Statement A uniform steel plate 18 in. square weighing 87.8 lb is suspended in the horizontal plane by the three vertical wires as shown. Calculate the tension in each wire ((a)TA , (b)TB, and (c)TC). Homework Equations \SigmaM=0 The Attempt at a Solution both A and B are...
  4. L

    Missing Components and 3D Vector Resolution by System of Equations

    1. Hi I am writing a program to calculate 3D vectors for visualization and I am testing textbook problems such as: "If vector c forms an obtuse angle with the 0Y-axis and is orthogonal to both vectors a = 3i + 2j + 2k and b = 18i - 22j - 5k Find the components of c if its norm...
  5. W

    Calculate Resultant Couple from 3 Couples in 3D

    Homework Statement Replace the three couples with a single resultant couple. Specify its magnitude and direction of its axis using angles to the positive x, y, and z axes. Homework Equations M = r x F (r cross F) The Attempt at a Solution I'm pretty sure I want to resolve the...
  6. P

    3D Velocity Of A Moving Object To A Stationary Object

    There are 2 objects. Object 1 is stationary and Object 2 is in motion. Object 1's position in the 3D world is (x=0,y=0,z=0). I have Object 2's velocity (also in x,y,z directions). I need to calculate the speed at which Object 2 is moving towards (or away from) Object 1. Keep in mind that this...
  7. J

    Difficult multivariable problem to find equation for 3d surface

    Homework Statement A given surface contains all points G such that the distance from G to the plane z=4 is double the distance from point G to the pt. (2, -3, 1). Find eqn for the surface. Homework Equations I thought the distance formula for a point to a plane would help, but I can tell...
  8. J

    Effortlessly Convert 3D Models to XYZ Coordinates | Affordable Software Options

    Hi guys, I'm looking for the following functionality out of a free, or cheap software. I'm very close using google sketchup but I appear to have hit a snag that nobody on their forums can figure out, so I come here. I want to be able to make a simple 3D model (so far I've just been using the...
  9. K

    3D 'perception' of the world we live in

    Hello I am not an expert in physics and only have minimal exposure. However, I have been struck by something recently that I wanted t bring up with experts in the field. I was discussing with a colleague the other day, the ability to imagine 3 dimensions. My colleague stated that most...
  10. S

    Calculate Tensions in a 3D Force System with Given Dimensions and Weights

    1. Homework Statement A system of cables suspends a crate weighing W = 420 lb. The dimensions in the figure are as follows: h = 20.9 ft, l = 5.70 ft, x = 7.05 ft, theta = 36.0 , and phi = 20.0. Determine TA, TD, and TE, the tensions in cable segments CA, CD, and CE, respectively. 2...
  11. S

    Mechanical Engineering 3D force system

    Homework Statement A system of cables suspends a crate weighing W = 420 lb. The dimensions in the figure are as follows: h = 20.9 ft, l = 5.70 ft, x = 7.05 ft, \theta = 36.0\circ, and \phi = 20.0\circ. Determine TA, TD, and TE, the tensions in cable segments CA, CD, and CE, respectively...
  12. D

    What would a 3D ball look like (in 3D) if it were partially in 4D space?

    What would a 3D ball look like if it were partially in 4D space when none of the 4th dimension is visible to the 3D observer? The equivalent question in flatland is: What would a 2D filled circle look like in flatland if it was partially in 3D? I think that there the answer would be a...
  13. S

    Solve 3D Force Systems Homework | F_A, F_B & F_C

    Homework Statement A system of cables supports a bucket. The dimensions in the figure are as follows: x_1 = 4.80 ft, x_2 = 1.70 ft, y_1 = 1.10 ft, y_2 = 3.30 ft, z_1 = 2.55 ft, and z_2 = 3.10 ft. If the bucket and its contents have a combined weight of W_1 = 17.5 lb, determine F_A, F_B, and...
  14. Y

    Points, Lines, and Planes in 3D Space Given 3 points find a plane

    Homework Statement A flashlight located at the origin, (0, 0, 0), shines a beam of light towards a flat mirror. The beam reflects off of the mirror at (8, 4, 1) and then passes through (10, 8, 5). What is the equation of the plane that contains the mirror? Express answer in linear form...
  15. T

    Mathematica Mathematica- Rotating a 2D plot into a 3D plot

    I have a plot of radius and temperature. I want to plot it in 3D by rotating it about the origin to produce a 3D plot. I can not figure out how to do this in Mathematica without doing it by hand and then plugging it into the Plot3D function. Any advice would be greatly appreciated. The...
  16. A

    3d parabola (projectile motion) to hit a target on an arbitrary plane

    Hi everyone, I'm a software engineer (sorry in advance if I made/will make some math mistake) and I'm trying to calculate the projectile motion from one point to hit a specific target in a 3d space so that the parabola will lie on an arbitrary plane. Is several days that I'm trying to...
  17. R

    MATLAB 3D vectors in matlab questions

    I am calculating the velocity of the air in front of a wing. I would like to plot the 3D vectors of the velocity on the same plot as the geometry of the wing. I have the two plots separately but I was wondering if there was anyway I could superimpose one on the other? Currently the geometry is...
  18. Char. Limit

    Questioning 3D Limits: What To Try Next?

    So, there was a big long post here with examples and such, but then my internet crashed. So screw the examples, I'll just get straight to my question. When seeing if a limit exists in 3d (with the limit being (0,0)), I noticed that we often try the lines x=0 and y=0 first. Are these always...
  19. C

    Intersection of 2 vectors in 3D, knowing the angle between them

    ** I accidentally posted this in the pre-calc math section first, but I think it's more applicable here...sorry** Homework Statement I need to find the intersection point of two vectors. For vector A, I have it's start point (0,0,0) and it's magnitude in components (-.41, .28, -.08)...
  20. C

    Intersection of 2 vectors in 3D knowing the angle between the two

    Homework Statement I need to find the intersection point of two vectors. For vector A, I have it's start point (0,0,0) and it's magnitude in components (-.41, .28, -.08). For vector B, I only know it's start point (-2.70, -.45, -.21) I also know that the angle between the two...
  21. W

    Basic Quantum Physics - Particle(s) in a (3D) Box

    Homework Statement A system of 20 neutrons are confined in the region 0<x<3L 0<y<L 0<z<2L With L=10^{-15}m If each eigenstate can accept 2 neutrons (corresponding to the 2 possible spin states) what is the total kinetic energy of the system? Homework Equations I found the...
  22. A

    Calculate Area of Triangle in 3D with Given Vertices | Homework Solution

    Homework Statement The vertices of triangle are (2,0,0) ; (0,3,0) ; (0,0,6) . Find the area of triangle. Homework Equations The Attempt at a Solution is it right that i put in determinant like Area of triangle = 0.5 | 2 0 0 | | 0 3 0 | | 0 0 6 | = 0.5 (2* 3 * 6)...
  23. A

    Calculating Curvature of 3D Hyperboloid - Parameters & Extrinsic Curvature

    How can I calculate the curvature of a 3D hyperboloid? I mean, what parameters do I need to calculate the intrinsic curvature? I guess to calculate the extrinsic curvature as seen from a 4D space I would just need a curvature radius, right? Thanks
  24. S

    3D surface of the land and ocean floor

    Can someone point me to 3D model of surface of the land and ocean floor of the Earth, or a grayscale elevation map so I could make my own 3D model from it. I was curious - I wanted to play a bit with such "flat" (rectangular i.e. not spherical) 3D model of Earth's relief by placing a flat...
  25. M

    How Do You Calculate Resulting Velocity Vectors in 3D Collisions?

    Hey, I've done quite a bit of Mechanics work in the past... But I really don't even know where to start here. For some work I'm doing, I need to calculate the resulting velocity vectors when 2 objects collide. These 2 objects can be any shape, any mass and going at any velocity independently...
  26. R

    Are the given lines in R^3 concurrent or parallel?

    Homework Statement Ok I have a bunch of questions, please bare with me and i'd appreciate it VERY much if you could help me with these! 1. Assume that you are given the equations of three planes. Without solving the system, describe a "test" with rationale, that you could use to determine...
  27. 6

    Need to find the volume of a 3d object

    I'm here again bothering you, I have this problem, but have no idea about how to start the problem solving: Homework Statement The USPS will accept packages only if the length plus girth is no more than 108 inches. Assuming that the front face is square, what is the largest volume package...
  28. B

    Understanding 3D Glasses: How Polarization Works and the Role of Mirrors

    I just got back from the cinema an hour ago and brought my 3d glasses home,i know these glasses work by only allowing light that oscillates in certain dirrections through the lenses,and each lense lies perpendicular to the other,allowing only one set of light through each lense,making you to see...
  29. W

    Mathematica Mathematica 3D plotting question

    I'd like to make a single 3D graph that contains a scatter plot and a plane. Ideally I'd like to import the data for the point from an excel file, but if I have to punch it in, I can find a few hours to kill. Anyway, can anyone help me with the code for this? I can get a 3D scatter plot where...
  30. S

    Plot some 2d graphs in a 3d fashion

    Hi, How can I plot some 2d graphs in a 3d fashion like the following picture using excel or matlab? Any idea is appreciated.
  31. A

    How to find the resultant of 3d vector?

    i have a vector ai+bj+ck is the resultant equal to sqrt(a^2+b^2+c^2). if so how do i explain it mathematically? i know the resultant of a 2d vector is equal to sqrt(a^2+b^2) and it can be proved from pythagoras theorem? any ideas??
  32. J

    Trouble Plotting 3D Graph with Two Variables and Matrix Data

    I have 2 variables and data points corresponding to them and so would like to plot this (I think using the plot3 function for a 3D graph) but I'm having trouble writing my code. Each variable ranges from 0 to 1 (in 0.1 intervals) and so this would be the x and z axis, and I have data points...
  33. P

    Finding 3D Models: A Resource Guide

    hi there, i am looking for the site about sharing 3D models, (like 3dcadbrowser) if you know, can you help me?
  34. J

    How Can 2D Plane Coordinates Be Transformed into 3D Coordinates?

    hi, so this is actually for a program I'm writing, but it's definitely more of a math question than a programming question. basically, i have an object that gets detected by a webcam attached to a computer. the object is just a piece of paper with a pattern on it, so it is, for the purpose of...
  35. J

    Filmmakers lost in the world of 3D animation and special effects

    When James Cameron made Titanic in 1997 it touched the hearts of people all around the world. I was a kid at that time knowing not much about love, pain, loss of loved ones, injustice around us, it still stands as one of my favorites; and it is always a new experience each time I see it. Rarely...
  36. H

    How to define a parabola in 3d coordinate system.

    Currently I am using a graphying application called "Autograph" and modeling a building with a dome shaped roof on top. I need to define parabolic shapes in 3d system. But i can't do it ( my math knowledge is pretty elementary) What would be the basic parabolic function in 3d that i can base...
  37. R

    Visualizing Temperature Distribution in 3D using MATLAB

    I have a temperature distribution T = T(x,y,z). I want to visualise it in MATLAB ( such that the colour(s) used by MATLAB in plotting should give me an idea of depth of temperature i.e whether its high or low compared to its neighbouring points). Please help
  38. J

    Align 3d object to vector by rotation

    i have the normal vector of a polygon face, and an object i wish to align to it by rotating it on XYZ. my up vector is (0,1,0). been trying to figure it out by using CrossProduct but i never get the right results. I already have CrossProduct and Normalize functions so I don't need the math for...
  39. M

    Linux 3D Plotter/Visualization

    Hey guys, quick question, I am in a little bit of a bind. I need a 3D plotter to post-proc some CFD runs at home. I have typically used plot3d in the past, but am having trouble getting it to compile on my machine (Ubuntu 10.04). I did a search and there's another program which can handle...
  40. Q

    MATLAB Creating 3D Animations in MATLAB for ODEs/PDEs

    I was tasked with making some animations of simple ODEs and PDEs in MATLAB for use in an undergraduate class. (Vibrating string, Heat Equation, Navier-Stokes)... I wrote some code and plotted some graphs, but I'm not seeing an option to animate along an axis in 2010a. Maybe I'm blind and...
  41. J

    How Do You Calculate Arc Points for Collision Detection in 3D Space?

    i'm having trouble creating a arc for check for collision similar to a grenade launcher type weapon and am not very good at math :/ i have the player position and the target position, now i just need to check every so often (let's say .1 units) along the outside of my ellipse to see if my...
  42. P

    3D elastic collisions of spheres: angular momentum

    Hi, I'm helping my friend with a space combat game he is programming. What I'm trying to figure out is how to model the collisions between spheres in 3D. So far I've figured out how to calculate final velocities of 2 colliding spheres using conservation of linear momentum. I found a...
  43. B

    MATLAB Exporting 3D Plots in MATLAB: How Can I Save and View Them in a Webpage?

    Hello, I was just wondering if anyone knows if there's a way to save a 3D plot in Matlab (eg a "surf(x,y,z)" plot) so that it is viewable outside of Matlab and so that you can still rotate the view etc? And in particular, so it can be viewed in a webpage? Something like LiveGraphics3D? I don't...
  44. 1

    Problem with 3d impulse and collisions

    Ok so I'm writing a 3D game that uses impulse to determine how things behave when they collide. In this game I have two cubes. Now the shape of each cube is defined by 9 spheres, sort of like this: http://mark.reid.name/images/figures/high-dim-3d.png Though in my game the middle sphere is...
  45. C

    3D Glasses: Diffraction or Not?

    Do 3d glasses use diffraction to work , because the ones i read about did not say anything about diffraction , but i shed a laser through my 3d glasses and it diffracted it perfectly on the wall , it had a center bright spot and then equally spaced dots from the center out .
  46. K

    Local min/max/saddle points of 3d graphs

    Hello, just got done taking a test and one problem kinda confused me. Homework Statement f(x,y) = e^x cos y find local min/max and saddle points Homework Equations fx = e^x cos y fy = -e^x sin y The Attempt at a Solution I answered that there were no critical points for...
  47. H

    Proving: Closed Curve Integral in 3D Space

    Homework Statement Giving 2 closed curves in 3-dimension space C1 and C2, prove that:\oint _{C1} \oint _{C2}\frac{(\vec{dl_2}.\hat{r_{12}})\vec{dl_1}}{r^2_{12}}=0 Where: _ \vec{dl_1} and \vec{dl_2} are the vector elements of the curves C1 and C2 respectively. _ r_{12} is the distance between...
  48. 1

    How do i find the direction of impulse in 3d?

    I'm writing a game that involves collisions with spheres. Anyway each sphere has both angular and linear velocity. These two spheres collide. I need to find the direction of the impulse between them (if that's the right wording). I tried just subtracting their linear velocity components like...
  49. S

    How to plot 3D data in 2D using Mathematica?

    Hello. I was asked to import a number of data to mathematica from an output file for wien2k (based in fortran). The thing is, I have to draw a graph that considers a matrix full of data in three dimensions, but the graph itself should only have two parameters. To sum up: how to represent 3D data...
  50. C

    What is the relationship between angles in a 3D trigonometry problem?

    Homework Statement [PLAIN]http://img708.imageshack.us/img708/1344/trig.jpg The angle c is separated from a 2d plane by angle b (perpendicular to the 2d plane). Angle a is angle c projected onto the 2d plane. What is a in terms of b and c? Homework Equations The Attempt at a...
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