The (3d) tag is for things related to 3-dimensions. For geometry of 3-dimensional solids, please use instead (solid-geometry). For geometry that is not on a plane, but otherwise agnostic of dimensions, perhaps (euclidean-geometry) or (analytic-geometry) should also be considered.

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0answers
29 views

What should happen to an impossible cube at a vertex?

I have automated the process of impossible-cube renders in Blender3D as an exercise. However, while the automator works fine as long as the intersection of the 'impossible' edge and the nearer edge is ...
0
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1answer
59 views

4 floats to determine a plane?

I am taking up a programming and asked to create a function for a certain problem. I was given this struct for a plane. However I can't make sense of this struct. How can 4 floats determine a plane in ...
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0answers
53 views

3D Animation of object flying straight towards a surface

Lets say we have the following the orthogonal(?) 4x4 matrix, which represents a world space transformation in a right-handed coordinate system. ...
1
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2answers
88 views

Finding the equation and plotting a plane using 3 points

restart; with(plots): with(VectorCalculus): I have 3 points in a plane defined in Maple as: ...
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1answer
289 views

Given 4 corner points of a rectangle in 3d space, how to find its “plane” equation?

Context: A BoundingPolytope defines a polyhedral bounding region using the intersection of four or more half spaces. The region defined by a BoundingPolytope is always convex and must be closed. ...
0
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1answer
70 views

How can I increase the resolution of a 3d plot in Sage to see all the details of the noodle? [closed]

I want to plot my noodle with a high resolution to see all the details. How can I achieve this with Sage? Here is my parametric, piecewise function: ...
0
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1answer
81 views

Basic 3D geometry problem

Here's 1 lb of butter What is the area of the wrapper around it? My answer : 4(11,5 * 6,3) = 289,80cm^2 2(6,3 * 6,3) = 79,38cm^2 289,80 + 79,38 = 369,18cm^2 A = 369,18cm^2 Teacher's answer : A ...
0
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1answer
24 views

Determining whether a 3-dimensional equations creates a horizontal or non-horizontal plane?

I am learning about graphing 3-dimensional shapes on x,y,z coordinates axis and am understanding everything for the most part. However, the thing that is continuously tripping me up is distinguishing ...
0
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1answer
82 views

How to calculate the points of the triangles making up an Octahedron?

Ok guys, I'm not a great mathematician but will try to work this as accurately as I can. I hope someone can help me. I am drawing some 3D objects and I am having trouble drawing an Octahedron. I ...
0
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0answers
70 views

Estimating the geometric shape of a point cloud without using the vertex information

Consider a point cloud format that describes 3D point clouds by vertices, triangle labels and normal vectors. If we miss the vertex information, is it possible to retrieve the lost data by triangle ...
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0answers
135 views

3D Game: Pitch Yaw Roll of a point

I have a flat elliptical plane and I'm trying to figure out how to represent it based on its direction. So I basically need to calculate its pitch, yaw, and roll. I have a camera at $C$, and a point ...
0
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0answers
66 views

Calculating center line of curved pipe

I want to have have a disk move vertically through a curved pipe. The pipe shape and size will be constant, the overall position and rotation in a 3d space will be random. Is it possible to calculate ...
0
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0answers
39 views

Normalization of Euler angle data

I have head motion data for several speakers. Because not every speaker sat in the exact same position during recording I have to normalize the data. One option to do this, I think, would be to ...
0
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0answers
95 views

$3$D transformation matrix to $2$D matrix

I have a $3$D affine transformation $4\times 4$ matrix. I need to convert it (project) to a $2$D affine transformation $3\times 3$ matrix, which looks like this: $3$D rotations are irrelevant and ...
0
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1answer
100 views

Ellipse Tangents in 3D

I know that we can find the tangent of the ellipse in 2D by taking the derivative of the equation defining the ellipse. But I'm little bit confused about finding the ellipse tangent in 3D. Where the ...
0
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1answer
46 views

Can I solve for the fractional volume of a hyperboloid?

This looks like a homework problem because it is. I'm stuck at the portion where I solve for fractional volumes. Suppose you are a part of a team designing a water tank in the shape of a hyperboloid. ...
1
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1answer
44 views

Find intersection of 2 parameterized planes

I have two parameterized planes, for example, {u, 0, v} and {u-1, v-1, 1}. And I have to find the parametric equation of the line that intersects both planes. By setting both planes equal to each ...
0
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0answers
44 views

Something about Manifold above 3

There two important facts about 4-manifold. Fact 1 There exists a 4-manifold which can not be triangulated. Fact 2 The homeomorphism problem for triangulated 4-manifold is unsolvable. Can ...
0
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2answers
40 views

3-space viewer?

Is there a software package that would allow visulaizing/rendering some example structures in 3-space? Specifically, I'm thinking of something that would provide a 3-D rendering of, say, 3-vectors ...
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0answers
19 views

How to find the values of transformstion and its center/axis? [duplicate]

I have system of two planes. Each plane is defined by three points, so I have their equations. One of these plane is stable, I can't perform any transformation. The second one is modifiable - rotation ...
1
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1answer
51 views

Find the intersection of two planes.

Find the intersection of the planes $x+(y-1)+z=0$ and $-x+(y+1)-z=0$. These two planes are 3-dimensional and I am confused on how to solve it.
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0answers
48 views

3d transformation in html5

I am trying to understand 3d-transformation in html5 and when it's rotation, scaling and moving - it is simple. But adding perspective confuses me. For example we have a rectangle: [400, 200], origin ...
0
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1answer
207 views

Equation of plane through intersection of planes and parallel to line

Find the equation of the plane through the intersection of the planes of $x-2y+z=1$ and $2x+y+z=8$ and parallel to the line: $\frac{x-3}{1} = \frac{y-1}{2} = \frac{z-2}{1} $ I'm facing difficulties ...
0
votes
1answer
31 views

Equation of a plane containing a point and a line

Find the equation of the plane containing the point (0, 7, -7) and the line $\frac{x+1}{-3} = \frac{y-3}{2} = \frac{z+2}{1}$ I'm not sure how to tackle this question, since the equation of the line ...
0
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2answers
56 views

How to create a nice sky route

I'm trying to find a nice algorithm to trace a sky route between 2 points of a planet. Here is where I am : https://dl.dropboxusercontent.com/u/17657227/migrationGlobe/index.html (or here ...
0
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1answer
515 views

Understanding the Equation of a Möbius Strip

I am in HL Math and trying to finish my IA. My topic is the Möbius band. The only problem is, I do not understand the formula that defines it and everywhere I have looked has just given me a ...
0
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1answer
36 views

Compare 2 coordinate systems in 3D space

How would i demonstrate that 2 coordinate systems are identical (that only a translation differentiate them) in 3D space? Let's say i have a coordinate system X Y Z and a coordinate system x y z.
8
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3answers
224 views

Eating a cake from the inside.

Imagine that you are in the centre of a cube of cake with a known size. In order to move you must eat the surrounding cake but you can only move within the restraints of the six obvious directions ...
3
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2answers
3k views

Formula to project a vector onto a plane

I have a reference plane formed by 3 points in R3 – A, B & C. I have a 4th point, D. I would like to project the vector →BD onto the reference plane as well as project vector →BD onto the plane ...
0
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1answer
48 views

How to compute the *vertical* distance between a point and a triangle in 3D?

The point is either above or under the triangle i.e. if you project the point and the triangle on the ground, the point lies in the triangle. I want the distance DD' (in dark red) on the Z axis of ...
0
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1answer
90 views

vectors in 3D space and Right-Hand Rule

Suppose we have three vectors in 3D space. My questions are: How we check if these vectors are satisfy the right-hand rule or not. I know that it's possible to make the three vectors satisfy the ...
0
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1answer
42 views

find a point in 3D space

Suppose we have $3$ fixed points $P_1, P_2, P_3$ in $3$-D space, their coordinates are $(x_i, y_i, z_i)$ for $i=1,2,3$. The problem is to find a point $P$ so that the distances from $P$ to ...
2
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0answers
93 views

What is the Area formed when a line is traced between two 3D curves?

This question is quite related to intersection of cylinders, Hyperbolic paraboloid and modelling. I am welding a trunnion to a pipe (both are hollow cylinders in different geometry). They intersect ...
1
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1answer
169 views

Can I define a plane given 2 points in xyz coordinates as well as roll angle about that vector?

I am working on a complex motion analysis, trying to calculate wrist angles in 3 dimensions. I have sensors placed as this diagram depicts and need both flexion/extension angles as well as ...
0
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1answer
162 views

Unit Vector Based on Angle with XY-YZ-XZ Planes

this may be a simple one but lets assume I have 3 angles (a,b,c) and I want to know what unit vector makes such angles with the XY-YZ-XZ planes. Another question is that I wanna know if a,b and c are ...
1
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1answer
684 views

Finding Rotation Axis and Angle to Align Two “Oriented Vectors”

In general, one can align a 3D vector $\vec A$ to another 3D vector $\vec B$ by rotating $\vec A$ around the axis $\| \vec A \times \vec B \|$ by the angle $\arccos{(\| \vec A \| \cdot \| \vec B ...
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0answers
89 views

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

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? ...
2
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0answers
21 views

The exact type of my 3d model

I have reconstructed vertical features (hole like objects lie on a vertical face) lie on two connected faces. To understand the situation, I say I have 2 walls with many windows and doors on ...
0
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1answer
78 views

Perspective projection onto y/z plane?

On wikipedia there is an article on 3d perspective projection onto the x/y plane. http://en.wikipedia.org/wiki/3D_projection#Perspective_projection How do I project onto the y/z plane? If i have a ...
2
votes
2answers
75 views

Height at 2D coordinate on a 3D rectangular surface

The Problem: How can I obtain every 3D coordinate on a rectangular surface given x and z? For those who are visual, picture looking down on the surface, and finding the height at where the x and z ...
1
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1answer
44 views

Most appropriate statistics for position error in 3D space.

I have some data on location in 3D space, and am analyzing a couple of models that are supposed to predict the said location. The data I have is a collection of distances as a function of time ...
0
votes
1answer
375 views

Find Equation of a Perpendicular Line Going Through a Point

I have the following parametric equation for line g: $$ x=3t\land y=-7+5t\land z=2+2t $$ I have to find the equation of a line perpendicular to $g$ and going through point $Q(3,-2,4)$ which lies on ...
0
votes
1answer
25 views

Normal to a 3 Dimensional line

So I have a 3D line: (0,0,0)+t(3,4,7) and I'm trying to find the normal of this. I know the gradient of the normal would normally be -1/gradient but I'm not sure how you would find the gradient with ...
0
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0answers
47 views

Euler rotation and manipulation of one angle

I've got an acceleration in a certain orientation (which I call local orientation). I known the Euler angles with respect to the global orientation (stored in orientation matrix). Calculating the ...
2
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3answers
45 views

rotations in 3d space

When looking at rotations in 3d space, does specifying two points (say point A is rotated to point B) determine the whole rotation, or is there a degree of freedom left?
0
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1answer
172 views

Calculating normals for a polygon mesh (3D computer graphics)

I want to write a program to generate arches, a common architectural form, and export them to a wavefront object format for sharing with various three dimensional graphics editors. To do this, I need ...
0
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1answer
58 views

Which of these rotation matrices represents a positive rotation in three-space about the y-axis?

This is what Wikipedia says: \begin{bmatrix} \cos \theta & 0 & \sin \theta \\ 0 & 1 & 0 \\ -\sin \theta & 0 & \cos \theta \\ \end{bmatrix} This is what I think it should ...
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2answers
59 views

Formal definition of plane

The formal definition of plane says that: A plane is a set of points such that if any two points are taken on it, all the points lying on the line joining these two points also lie on the plane. The ...
-1
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2answers
128 views

Identifiying the next point on the surface of a cube ( or 3D object )

I have a cube of unit length. Each face of the cube is divided into 10 x 10 equal segments. Consider an object of size equal to that of a segment moving through the surface of the cube ( or any 3D ...
2
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0answers
48 views

Finding point of contact of a sphere in an image

I have an image, in which there is a table, and on this table, a sphere. I would like to find the point of contact between the sphere and the table. This point can be the center of the sphere, for ...