Reconciliation of real life and drawing terms

# Thread: Reconciliation of real life and drawing terms

1. ## Reconciliation of real life and drawing terms

Horizon line of a drawing, is representing the eye level in the real world.

But, say in 2 point perspective, what are the 2 points, representing in the real world?

2. The Two Giant Dots on the Horizon line.

(On day I will travel and visit each one of them. . .)

--Right after I see the Pot Of Gold at the End Of the Rainbow.

3. Books on perspective, like if you type in perspective for artists in amazon or even google, will give you a great deal of info on the subject.

Last edited by OmenSpirits; August 21st, 2012 at 02:37 AM.

4. Still the eye level. They are just different vanishing points on the same horizon. Every object has its own multiple vanishing points. The vanishing points for an object change based on the location of the viewing eye. Basically the vanishing points are determined by the shape of the object. Usually they are defined by where the object's angles intersect on the horizon line.

5. Originally Posted by Kamber Parrk
The Two Giant Dots on the Horizon line.

(On day I will travel and visit each one of them. . .)

--Right after I see the Pot Of Gold at the End Of the Rainbow.

I know that it is two dots on the horizon line. My question is what does it represent?

6. They represent the intersection of the 90 degree cone of vision with the horizon line as projected from the station point. (With a 60 degree cone, of course, being the maximum theoretical limit of undistorted vision).

7. ## The Following 2 Users Say Thank You to Kamber Parrk For This Useful Post:

8. Originally Posted by iamcreasy
I know that it is two dots on the horizon line. My question is what does it represent?
It doesn't represent anything. It's a quirk of the fact that your field of vision is a cone. The proportion of the cross section of the cone that each object takes up gets smaller the furter back you go, so parallel edges look like they converge. Each set of parallel lines appears to converge on some imaginary point, but the points are all different between sets. There's really no such thing as 2-point perspective at all, it's a simplified model people give to art students so they can draw something that looks right-ish without worrying about what's happening in the field of vision.

9. Originally Posted by vineris
It doesn't represent anything. It's a quirk of the fact that your field of vision is a cone. The proportion of the cross section of the cone that each object takes up gets smaller the furter back you go, so parallel edges look like they converge. Each set of parallel lines appears to converge on some imaginary point, but the points are all different between sets. There's really no such thing as 2-point perspective at all, it's a simplified model people give to art students so they can draw something that looks right-ish without worrying about what's happening in the field of vision.
Yes. But, it didn't answer my question. I get the fact that 2 point perspective doesn't exists. But, why exactly they are on the horizon line?

10. iamcreasy,

vineris and I have explained the same thing to you in slightly different ways.

The points are simply the intersection of a cone that represents the region of the eyeball's vision with a line that represents the eye level.

This is all brutal, stone cold geometry that's been worked out since the 1400s.

11. Originally Posted by Kamber Parrk
They represent the intersection of the 90 degree cone of vision with the horizon line as projected from the station point. (With a 60 degree cone, of course, being the maximum theoretical limit of undistorted vision).
But the intersection only occurs when the eye level and cone of vision happens to be on the drawing area.

Originally Posted by Kamber Parrk
The points are simply the intersection of a cone that represents the region of the eyeball's vision with a line that represents the eye level.
Say you are drawing only the top potion of a high rise building standing on the front street. In this picture your eye level is way below the view able area. So, no intersection.

This is my confusion.

12. Originally Posted by iamcreasy
Say you are drawing only the top potion of a high rise building standing on the front street. In this picture your eye level is way below the view able area. So, no intersection.

This is my confusion.
You're complicating your initial scenario-- 2 point perspective-- where the central visual ray is parallel to the ground, with a scenario where the central visual ray is elevated and the picture plane is no longer perpendicular to the ground.

13. Originally Posted by iamcreasy
Yes. But, it didn't answer my question. I get the fact that 2 point perspective doesn't exists. But, why exactly they are on the horizon line?
Since all perspective is really 3-point perspective (or I guess possibly 4-point...), there are vanishing points which are not on the horizon line.

14. In 2 point perspective where the eye level isn't on the drawing area, how the vanishing points are created? Here cone cross section can't intersect with eye level.

I am not worrying about 3 point or something more complicate right now.

15. You're getting confused with a 3-point perspective photo. That photo still deals with the same principles that were explained in the thread, just the horizon line has been moved down and a third vanishing point has been added in the sky somewhere.

16. Wow Keeptime. Your digital handwriting is almost worse than mine.

17. It's abstract handwriting.

I was using the mouse in MS Paint.

18. ## The Following User Says Thank You to keeptime For This Useful Post:

19. Nothing more than two points in an ideal situation where parallel lines seem to converge on the horizon. The horizon is really a continuous series of infinite points. Most modern-ish, man-made structures have parallel faces and edges so it works. Try applying perspective to a Frank Gehry building.

Edit: VPs are not always on the horizon...it depends on where the parallels point. And yeah, that example is 3 point perspective.

20. ## The Following 2 Users Say Thank You to JeffX99 For This Useful Post:

21. iamcreasy, you still place the left and right vp's as though you were looking at the hl. Then, for point 3, consider yourself to be looking up (or down).

22. Originally Posted by vineris
Since all perspective is really 3-point perspective (or I guess possibly 4-point...), there are vanishing points which are not on the horizon line.
The horizon line still governs-- you get 3-point when either an object or the picture plane is inclined.

23. Jester Level 8 Gladiator: Thracian
Join Date
Jun 2007
Location
Toronto, Ontario
Posts
1,143
Thanks
9
Thanked 397 Times in 272 Posts
Follows
0
Following
0
Originally Posted by JeffX99
The horizon is really a continuous series of infinite points.
Whoa! Infinite points! This runs me totally hot: care to elaborate on this?

24. Infinite points means... that although the lines appear to converge at the horizon, they in fact never get any closer to each other. The distance makes them appear to intersect, but the scale goes down in proportion to the distance. So there is nothing to stop the vanishing point from being infinitely far away except that optically they have the illusion of convergence. Anywhere on the line is a point, thus infinite points.

Edit: Also a object can have infinite vanishing points based on the complexity of its geometric shape. Each surface or sets of parallel angles on the object has their own vp... which having re-read Jeff's post seem to be more what he's implying.

Last edited by Shorinji_Knight; August 22nd, 2012 at 01:32 AM.

25. ## The Following 2 Users Say Thank You to Shorinji_Knight For This Useful Post:

26. Yep.

Linear perspective isn't that tough. It is simply a construction approach that helps us translate what we see onto a two-dimensional surface. The key is to remember that parallel edges appear to converge in the distance. That's it. If the parallel eges are also parallel to the ground they converge at a VP somewhere on the horizon. If they are not parallel to the ground, as in a sloping roof edge or some other tilted plane like a ramp, they converge to their own VP.

Again, all you have to remember is parallels converge in the distance.

From Loomis' "Successful Drawing" - an excellent section on perspective:

27. ## The Following 3 Users Say Thank You to JeffX99 For This Useful Post:

28. Originally Posted by JeffX99
Yep.

Linear perspective isn't that tough. It is simply a construction approach that helps us translate what we see onto a two-dimensional surface. The key is to remember that parallel edges appear to converge in the distance. That's it. If the parallel eges are also parallel to the ground they converge at a VP somewhere on the horizon. If they are not parallel to the ground, as in a sloping roof edge or some other tilted plane like a ramp, they converge to their own VP.

Again, all you have to remember is parallels converge in the distance.

From Loomis' "Successful Drawing" - an excellent section on perspective:
My problem usually is the rate of convergence of the parallel lines isn't in harmony. Their difference in the rate makes the image look not-the-way-I-want-it-to.

That's why I was asking this question from the opposite direction. What if I start drawing the picture solely based on the horizon line and gradually sort out the vp's based of feelings.

29. Yet another person who asks general, vague questions for what turn out to be specific, personal reasons, but won't show their work so they could actually get some real help with what their problem really is rather than what they think it is.

30. ## The Following 4 Users Say Thank You to Elwell For This Useful Post:

31. I'd be hesitant to draw as well if I thought it was this complicated.

32. ## The Following 2 Users Say Thank You to Star Eater For This Useful Post:

33. Originally Posted by iamcreasy
What if I start drawing the picture solely based on the horizon line and gradually sort out the vp's based of feelings.
How about you start drawing, post it and ask. If not...let's not waste people's time.

34. ## The Following User Says Thank You to Arshes Nei For This Useful Post:

35. Jester Level 8 Gladiator: Thracian
Join Date
Jun 2007
Location
Toronto, Ontario
Posts
1,143
Thanks
9
Thanked 397 Times in 272 Posts
Follows
0
Following
0
Originally Posted by Shorinji_Knight
Infinite points means... that although the lines appear to converge at the horizon, they in fact never get any closer to each other. The distance makes them appear to intersect, but the scale goes down in proportion to the distance. So there is nothing to stop the vanishing point from being infinitely far away except that optically they have the illusion of convergence. Anywhere on the line is a point, thus infinite points.
Vanishing points do not exist in space: they only exist in the picture plane. In a previous life, I taught Mathemetics; I hanged students for less

36. ## The Following 2 Users Say Thank You to eezacque@xs4all.nl For This Useful Post:

37. As I said vanishing points are an optical illusion. I refer you to the Loomis diagram that Jeff posted above. The men working on the roof have vanishing points in space because the lines never actually converge. They only seem to.

38. Originally Posted by eezacque@xs4all.nl
Vanishing points do not exist in space: they only exist in the picture plane. In a previous life, I taught Mathemetics; I hanged students for less
Hmmm....semantic BS I say. They certainly appear to exist in space as in railroad tracks, roads, etc. due to the phenomenon of...perspective. And of course they only exist in the picture plane just as the drawing only exists in the picture plane. If I understand your point correctly?

39. Jester Level 8 Gladiator: Thracian
Join Date
Jun 2007
Location
Toronto, Ontario
Posts
1,143
Thanks
9
Thanked 397 Times in 272 Posts
Follows
0
Following
0
Originally Posted by JeffX99
Hmmm....semantic BS I say. They certainly appear to exist in space as in railroad tracks, roads, etc. due to the phenomenon of...perspective. And of course they only exist in the picture plane just as the drawing only exists in the picture plane. If I understand your point correctly?
You understand my point. Although vanishing point appear to exist in space, they don't exist in space. That is not semantic BS, that is mathematics.

There is an old joke about two idiots who get a job with the railroad. Their manager really wants to get rid of them, so he takes them to the railroad tracks and shows them how in the distance the tracks come closer and closer until they finally meet. The two idiots agree that is a dangerous situation, and are told to go and fix it.

So, they follow the tracks with a measuring tape, to find the point where things start to go wrong. After hours of walking, one of them looks over his shoulder and says to the other: "How is this possible, we have completely missed the point where the tracks touch? We have walked way too far!"

40. ## The Following User Says Thank You to eezacque@xs4all.nl For This Useful Post:

Page 1 of 2 1 2 Last