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Questions tagged [3d]

For things related to 3 dimensions. For geometry of 3-dimensional solids, please use instead (solid-geometry). For non-planar geometry, but otherwise agnostic of dimensions, perhaps (euclidean-geometry) or (analytic-geometry) should also be considered.

This tag is for things related to 3-dimensions. For geometry of 3-dimensional solids, please use instead . For non-planar geometry, but otherwise agnostic of dimensions, perhaps or should also be considered.

Learn more about 3-dimensional space here.

3724 questions
42
votes
4 answers

Calculate distance in 3D space

Imagine I want to determine the distance between points 0,0,0 and 1,2,3. How is this calculated?
Simon Verbeke
  • 627
12
votes
2 answers

Mathematical description of a corncob

I'm trying to figure out how I can make a paper model of the corncob water tower in Rochester, Minnesota for my N-scale train layout. The best I can find is this: http://www.korthalsaltes.com/model.php?name_en=hebdomicontadissaedron Is there an…
Paul Reiners
  • 817
7
votes
4 answers

Find out whether two rectangles are intersecting in 3D space

I've got two rectangles in 3D space, each given by the coordinates of their 4 corners. They are not axis aligned, meaning their edges are not necessarily parallel/perpendicular to the world axes. Each rectangle can have any orientation. Is there an…
spl0uf
  • 71
5
votes
2 answers

Determining complexity of a 3D shape

This is my first foray outside of stack-overflow, so I hope this is an acceptable forum for this question. I want to calculate a 'complexity' index based of 3D models. Currently I'm calculating the surface area and dividing it by the volume - but…
Galaxy
  • 103
4
votes
3 answers

Convert direction vector to euler angles

How do I convert a direction vector to euler angles? I need to change the position of a character's head in a Java program that I'm writing. The pose of the head uses euler angles. I know the direction vector that it needs to face to.
Elite_Dragon1337
  • 153
3
votes
3 answers

Can you find a ellipse so that its image is a circle?

This is a "fun" question and I have already a solution. I asked this question so that I may see a different approach or an elegant solution. Let $P$ be a plane with equation $x+y+z=1$. Find an ellipse on $x,y$ plane so that its "shadow" on $P$ is a…
mesel
  • 14,862
3
votes
2 answers

A 3d line intersecting 2 other 3d lines

The equation of the line parallel to $\frac{x}{2} = \frac{y}{3} = \frac{z}{4}$ and intersecting the lines $9x + y + z + 4 = 0 = 5x + y + 3z$ & $x + 2y - 3z - 3 = 0 = 2x - 5y + 3z + 3$ My solution is as follow $\frac{{x - a}}{2} = \frac{{y - b}}{3}…
Samar Imam Zaidi
  • 8,800
3
votes
1 answer

3D rotation about z axis

I am struggling to understand the 3D rotation. The initial object position is A(x1,y1,z1). We need rotate it into A′(x2,y2,z2) about z-axis by angle θ.And we take P be the any point in z-axis. It makes ∠APS=ϕ. Now we find cosϕ=PS/OP=x1/r⇒x1=rcosϕ.…
S. M.
  • 1
3
votes
1 answer

Equation in 3d-Space

Consider we have 3 fixed points A,B and C also,We have this Equation : $MA^2+MB^2+MC^2=30$. What does this Equation represent in 3d-Space,( where M is such a Non-fixed point in that space)? Suppose…
Yaser Tarek
  • 81
3
votes
1 answer

Calculate weighted mean point from array of 3D point.

I have a set of points whose positions are represented by 3D vectors. Each point has the associated weight in range from 0 to 1. The sum of all weights doesn't equal to 1. How should the weighted mean point be calculated from the whole set of…
BartoNaz
  • 133
3
votes
2 answers

find coodinates of orthocentre in 3d plane

The plane $$2x+y+2z=9$$ intersects te coordinate axes in $A$, $B$, $C$ now we have to find the coordinates of the orthocenter of the triangle $ABC$. I tried and get to know that the coordinates of triangle above…
a25bedc5-3d09-41b8-82fb-ea6c353d75ae
  • 1,769
2
votes
2 answers

How to check if point is within a rectangle on a plane in 3d space

Please refer to this image for this question-> I have a 3d bounded box (in green). I also have a 3d line (in red) I know the points a, b, c, d, e. They are points in space with x, y, z, coordinates. I also know that a, b, c, d, and e, lie on the…
DaManJ
  • 121
2
votes
4 answers

Height of the tetrahedron through Euclidean geometry

The edge lengths of a tetrahedron ABCD are: AD=BD=CD=1; AB=2sin(a/2), BC=2sin(b/2), CA= 2sin(c/2) where a,b and c are angles ADB,BDC and CDA respectively. What will be the height of tetrahedron from vertex A? I know this can be done easily for any…
Aniket Harit
  • 93
2
votes
2 answers

Calculate Points on normale plane alinged to vector

I am writing a Program and I would like to calculate the $3\text{D}$ coordinates of $2\text{D}$ Points on a normal plane aligned to a vector, in order to rotate the $2\text{D}$ circle in $3\text{D}$ Space. Therefore I would need to calculate a…
Kipotuzer TT
  • 23
2
votes
0 answers

Finding a simple template within a 3D point cloud

I want to find a template - defined by 5 coplanar, non-collinear points - within a point cloud of say 100 3D points, in the most efficient way possible. I know there is the ICP (Iterative Closest Point) algorithm for these types of problems but I am…
jellybean
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