What's that word on the tip of my tongue?

conorh91

…where two parallel lines intersect and take up one another's parallel positions?



This word has been on the tip of my tongue for the past 10 minutes and is driving me bananas. I'm pretty sure it begins with the letter c. Does it contain the word 'legged'? It may or may not be a military manoeuvre.

Sorry if this is the wrong place to ask, but there's nobody else around and I'm in the middle of writing something and have now completely lost my train of thought.

the_syco

Intersection? Crossing? Transversal?

conorh91

Negative lockstep!

I walked away from my computer, and it came to me while I was in the shower. Forgot about this thread until now.

braddun

coplanar

braddun

coplanar

Homogeneous coordinates, introduced by August Ferdinand Möbius, make calculations of graphics and geometry possible in projective space. Homogeneous coordinates are a way of representing N-dimensional coordinates with N+1 numbers.

To make 2D Homogeneous coordinates, we simply add an additional variable, w, into existing coordinates. Therefore, a point in Cartesian coordinates, (X, Y) becomes (x, y, w) in Homogeneous coordinates. And X and Y in Cartesian are re-expressed with x, y and w in Homogeneous as;
X = x/w
Y = y/w

For instance, a point in Cartesian (1, 2) becomes (1, 2, 1) in Homogeneous. If a point, (1, 2), moves toward infinity, it becomes (∞,∞) in Cartesian coordinates. And it becomes (1, 2, 0) in Homogeneous coordinates, because of (1/0, 2/0) = (∞,∞). Notice that we can express the point at infinity without using "∞".

tac foley

I was just going to say that, myself.

tac

MathsManiac

Just in case anyone is labouring under any delusions on the matter, I would like to confirm, as a person who fully understands things like coplanarity, homogeneous co-ordinates, and so on, that braddun's post is completely irrelevant claptrap.

tac foley

MathsManiac wrote: »

Just in case anyone is labouring under any delusions on the matter, I would like to confirm, as a person who fully understands things like coplanarity, homogeneous co-ordinates, and so on, that braddun's post is completely irrelevant claptrap.

'That would be an ecumenical matter'.

tac