Author |
Topic: Point of view (Read 543 times) |
|
Noke Lieu
Uberpuzzler
pen... paper... let's go! (and bit of plastic)
Gender: 
Posts: 1884
|
 |
Point of view
« on: Feb 8th, 2010, 8:57pm » |
 Quote  Modify
|
I'm stumped.
I'm thining of one point perspective drawings.
The axioms are, as far as I know:
All parallel lines converge in this projection.
The points at which they converge (Vanishing Points) lie on the Horizon Line.
and that's about it (for one point perspective, in a handwavy way).
I'm perfectly comfortable with parallel lines running horizontally across the page converging at a vanishing point that's infinitely far along the horizon line. In fact, thinking about it makes me happy.
My question is "Where do parallels that run vertically on the page converge?"
|
|
 IP Logged |
a shade of wit and the art of farce.
|
|
|
towr
wu::riddles Moderator
Uberpuzzler
Some people are average, some are just mean.
Gender:
Posts: 13730
|
|
Re: Point of view
« Reply #1 on: Feb 9th, 2010, 3:23am » |
Quote Modify
|
I'm not sure what you're asking. Lines that are parallel on the page aren't parallel in the scene you're drawing. (Except when they're also parallel to the horizon.)
|
|
IP Logged |
Wikipedia, Google, Mathworld, Integer sequence DB
|
|
|
Immanuel_Bonfils
Junior Member
Posts: 114
|
|
Re: Point of view
« Reply #2 on: Feb 9th, 2010, 5:30am » |
Quote Modify
|
Couldn't find the beginning of thuis riddle...
|
|
IP Logged |
|
|
|
Grimbal
wu::riddles Moderator
Uberpuzzler
Gender:
Posts: 7527
|
|
Re: Point of view
« Reply #3 on: Feb 9th, 2010, 6:23am » |
Quote Modify
|
This is about a projection of 3d space on a 2D plane.
The line of sight is the axis going from your eye through the plane, perpendicularly.
If that line aims at the horizon, then it is horizontal, the projection plane is vertical and all vertical lines remain parallel on the projection.
If that line of sight is going upwards, then there is a vanishing point over the horizon. That is the point where a line going up vertically from your eye meets the projection plane. All verticals converge to that point. Imagine looking at a skyscraper from the street.
If the line of sight is going down, you have a vanishing point below the horizon. Imaging looking down an elevator shaft.
|
| « Last Edit: Feb 9th, 2010, 6:25am by Grimbal » |
IP Logged |
|
|
|
Immanuel_Bonfils
Junior Member
Posts: 114
|
|
Re: Point of view
« Reply #4 on: Feb 9th, 2010, 6:44am » |
Quote Modify
|
Thanks, but I knew this stuff about prespective or/and projective. I thought it was a continuation of som riddle (it's looks like) but seems its the starting of...
Doesn't vertical lines in the scene be represented by verical lines in the page?
I mean, with the line of view being horizontal, the vertical lines are parallel...
|
| « Last Edit: Feb 9th, 2010, 6:55am by Immanuel_Bonfils » |
IP Logged |
|
|
|
Grimbal
wu::riddles Moderator
Uberpuzzler
Gender:
Posts: 7527
|
|
Re: Point of view
« Reply #5 on: Feb 9th, 2010, 4:56pm » |
Quote Modify
|
yes, when the line of sight aims at the horizon, it is horizontal and the verticals are parallel.
|
| « Last Edit: Feb 9th, 2010, 4:58pm by Grimbal » |
IP Logged |
|
|
|
Noke Lieu
Uberpuzzler
pen... paper... let's go! (and bit of plastic)
Gender:
Posts: 1884
|
It is the continuation of some sort of riddle, one that I've been playing with. I'm writing teacher support notes on perspective.
And as I'm working on it on my own, I thought I'd consult better brains than mine.
I'm going to use fairly layman language to describe what I'm struggling with...
Imagine a square grid on the floor, stretching off into the distance.
There are parallel lines running perpendicular to the image plane. Ther converge at the "Vanishing Point".
There are other parallel lines, for example those of the diagonals of the squares.
They also converge, but at a diagonal vanishing point.
There are an *ahem* rather large number of diagonal vanishing points. The closer to being parallel to the plane lines are, the further from the vanishing point the DVP is.
The parallel lines running parallel to the image plane therefore converge at a spot infinitely far along the horizon line.
(and now I can't remember what my point was...  )
It was struggling with the distinction between 1 and 2 point perspective., and representation of dimensions, how they didn't match...
|
|
IP Logged |
a shade of wit and the art of farce.
|
|
|
rmsgrey
Uberpuzzler
    
Gender:
Posts: 2873
|
|
Re: Point of view
« Reply #7 on: Feb 10th, 2010, 8:27am » |
Quote Modify
|
With a horizontal line of sight, horizontal parallel lines meet on the horizon, vertical parallels never meet, and parallel lines which are neither horizontal, nor perpendicular to the line of sight, meet at some random point on the viewing plane.
The difference between 1-point and 2-point perspective lies in how many sets of parallel lines not perpendicular to the line of sight are allowed to exist in the picture - in one point perspective, parallel lines are either perpendicular to the line of sight, or parallel to each other (and often to the line of sight); in 2-point perspective, there are two sets of mutually parallel lines not perpendicular to the line of sight.
In general, you can have arbitrarily many vanishing points, each representing a set of parallel lines with a different direction in object-space.
|
|
IP Logged |
|
|
|
|
RIDDLES SITE
WRITE MATH!
Home 
Help 
Search 
Members 
Login 
Register
Reply
Notify of replies
Send Topic
Print