Here’s a simple computational geometry problem. I am trying to figure out the value at an point of two line segments based off of the values at both of one of the segment’s endpoints.
The problem is that I don’t exactly know the
best way of going about finding the value at one of those points.
Here is a reference figure.
Given values
(X_C, YC) = F_C
(X_D, YD) = F_D
How can I calculate the value of F_E, where F_E = (X_E, Y_E), where E is the point on the segment CD, where CD intersects with the line AB?
(Extraneous details inside)
[more inside]
posted by oceanjesse
on Dec 5, 2012 -
10 answers
Help me remember this old video series that used early computer/video animation to illustrate geometry/calculus concepts.
[more inside]
posted by Wild_Eep
on Aug 6, 2012 -
4 answers
Calling geographers: has anyone applied the idea of topological prominence to population density?
[more inside]
posted by miyabo
on Apr 27, 2012 -
7 answers
What is this geometric figure?
Is there a name for the figure inscribed in the circle
here?
posted by vash
on Apr 8, 2012 -
4 answers
Looking for tips on implementing drag and drop that snaps to the nearest point on a polygon.
[more inside]
posted by syzygy
on Mar 29, 2012 -
13 answers
I'm looking for an awesome video/discussion topic that relates to street maps - something appropriate for a HS geometry course.
[more inside]
posted by ch3cooh
on Jan 3, 2012 -
7 answers
Several years ago, I saw a website with a fun little flash or javascript applet thingy where you could build little tensegrity structure creatures, then have oscillating movements applied to the pieces, so that the structures would seem to "walk". I don't remember what it was called! From memory, one of the simpler structures looked sort of like
this. What was it? Is it still online?
[more inside]
posted by rivenwanderer
on Jan 3, 2012 -
4 answers
Consider two rings that are intertwined. (These lie in 3-dimensional space, but when you draw it on paper it looks like a venn diagram.) In 3-dimensional space they cannot be unlinked. The questions is, if you had one more dimension, can you unlink them?
posted by gzimmer
on Jul 15, 2011 -
14 answers
Geometry question -> Determine X and Y from distance along a straight line, or, how do I find the lengths of A and B if I know the length of C and the ratio of A to B in a right triangle?
[more inside]
posted by syzygy
on Jul 4, 2011 -
9 answers
I'd like to be able to watch the Macy's fireworks from my dad's roof on the Upper West Side. How can I figure out if I'll be able to see them? I have some variables, heights, distances, and video...
[more inside]
posted by thebazilist
on Jul 1, 2011 -
7 answers
How does walking around on a hyperbolic plane differ from a euclidean one?
[more inside]
posted by Hactar
on May 20, 2011 -
9 answers
Could someone help me with this geometry problem? Cylinder with a plane bisecting it at a 45° angle...
[more inside]
posted by Tchad
on May 2, 2011 -
19 answers
I'm writing a graphics app where I'm generating a simple gear transmission system with a variable number of gears each with variable number of teeth and placed at random orbits around each other. I generate gears in succession, placing and rotating each with respect to its parent/driver gear before moving on to the next. The problem I'm having is how to determine the initial orientation of each subsequent gear such that its teeth are properly meshed with that of its driver.
[more inside]
posted by Epsilon-minus semi moron
on Oct 25, 2010 -
6 answers
Given a set of points on a plane (or in a bounded region), how do I find the radii of circles centered at each point that provide the best covering?
[more inside]
posted by Eamon
on Oct 19, 2010 -
28 answers
How should I colour each isocoles tetrahedron in a chain of 24 using three colours, so that when I fold up the chain into a rhombic dodecahedron each rhombic face is a single colour and is different to its neighbours?
[more inside]
posted by Brentusfirmus
on Sep 16, 2010 -
10 answers
MathFilter: Is there a relationship between the number of dimensions in a Euclidean space and the number of regular tessellations of that space?
[more inside]
posted by jedicus
on May 2, 2010 -
10 answers
Where can I find free geometry text diagram creating software? Even not so free software seems to not do what I want. I want to be able to draw simple plane geometry figures (e.g. right triangles) with markings (e.g. to indicate lines are perpendicular or angles are equal) and labels (e.g. of a line's length or the name of an angle) and such.
[more inside]
posted by Obscure Reference
on Apr 23, 2010 -
13 answers
What is the graph or plot called which:
- is an equilateral triangle
- has three axes
- each axes is perpendicular to a side of the triangle?
[more inside]
posted by Peter Petridish
on Oct 28, 2009 -
10 answers
Photoshop Question: is there a way to get a count of pixels contained within any (irregularly shaped) selection/layer?
[more inside]
posted by unmake
on Sep 10, 2009 -
2 answers
What software can I use to make a photo collage using non-rectangular photos?
[more inside]
posted by soelo
on Jun 9, 2009 -
3 answers
Is there an equation that defines the change in apparent size as a function of distance from the viewer? Basically, if I'm looking at a set of railroad tracks head on, if one plank is like 10 ft away, it appears to be one size. The same plank 20 ft away appears smaller. What is the relative size difference? Put another way, how big does a 1ft line appear to be at 10 ft, at 20 ft, etc.?
[more inside]
posted by miasma
on May 16, 2009 -
15 answers
Hi I'm trying to find a piece of art - a series of lights attached to wooden arms whose tips trace some sort of toroidal geometry. At high speeds the armature disappears and the lights form volumes as luminous wireframes, like synchronised mechanical sparklers.
[more inside]
posted by doobiedoo
on Mar 5, 2009 -
5 answers
3-D folks, Mathematicians, and Artists: Trying to create my own
Trompe-l'œil / forced perspective illusionary image to hang on my wall
(e.g. the awesome parking garage signage everyone's already seen... more examples here, and here). I'm having trouble faking it with 2-D programs, and the math is puzzling me.
[more inside]
posted by jjjjjjjijjjjjjj
on Jan 9, 2009 -
34 answers
Math filter: How many equally sized rectangles will fit into a circle, and how should I arrange them in order to make the best-looking approximation?
[more inside]
posted by brandnew
on Aug 17, 2008 -
9 answers
How can I tile a sphere using the minimum number of differently shaped units? I have a 3 meter diameter sphere and I need to tile it using units that are each about 400 square cm (ie like a 20 x 20cm square). The units must be flat (ie, not spherical triangles).
[more inside]
posted by silence
on Jun 2, 2008 -
14 answers
How far would I need to travel from a tower 100 feet high before the sight of it would become obscured by the horizon?
[more inside]
posted by grrlaction
on May 4, 2008 -
20 answers
I read a book sometime in elementary school (early/mid 90's) that I've been trying to find. It had to do with geometry and math and platonic solids and origami (I believe there were several nods to Flatland). The plot had something about evil army men toys and a boy having a fever dream. I think the cover had a picture of the boy riding a manta ray.
[more inside]
posted by rivenwanderer
on Mar 31, 2008 -
3 answers
My geometry teacher in high school in 1984 showed us
this puzzle. I was only half paying attention, but I believe the goal was to draw a line that intersected each segment only once.
[more inside]
posted by mecran01
on Jan 6, 2008 -
15 answers
Does anyone teach a course in Synergetic Geometry in Los Angeles??? In the U.S.????
[more inside]
posted by goalyeehah
on Aug 27, 2007 -
1 answer
3D Trig question: I have a 2D square in 3D space (a Face). I know the positions of the four corner vertices in form x,y,z. How do I calculate the rotation in degrees (Euler angles) as relative from the center of the face?
I want to end up with degrees of rotations around x-axis,y-axis,z-axis. Bonus if you can write it in pseudocode.
posted by pooya
on May 9, 2007 -
7 answers
Vector Geometry Filter: I'm working in matlab and need to transform a surface to match an arbitrary angle. I have the unit vector of the new normal (and the original normal is in the Z axis (0 0 1))...however i'm not sure how to rotate one normal to another (i know, i know, it sounds very simple really...)
[more inside]
posted by NGnerd
on Oct 23, 2006 -
5 answers
Does anybody remember those circular templates that makes infinite radial patterns with colored ball pens? They had concentric holes for which to anchor a ballpoint against an outer axle, and then you change colors corresponding with the holes? What do you call those? Is it called anything at all?
posted by azul
on Sep 18, 2006 -
21 answers
