perspective vp.s

[wizard509]

I thought this might be of use to someone here.


https://www.youtube.com/watch?v=xbITwqiuyUg

[Boy]

Well, thanks Larry, now I'm even more confused! :-)

Especially her use of the term vanishing point This is how I always understood it: the point at which receding parallel lines viewed in perspective appear to converge. She seems to have a different interpretation or I fail to understand how it matches this definition.

[handrawn]

interesting Larry

there is nothing in the video that contradicts the definition of vanishing points

the lady is pointing out that all vanishing points exist on the horizon line, and she is giving a basic run down on how to find a horizon line in a picture where there is no visible horizon, using eye level as the reference instead

nature is complicated and visually exists in a multitude of z-planes, so you cannot just pick any old set of 'straight lines' you need that reference line

[wizard509]

I thought this is an interesting explanation and hoped some might find it useful, VP's can be very complicated and not all are on the horizon for instance on a building with a pitched roof drawn in perspective the line of the nearest slope is not simply parallel to the slope angle of the furtherest slope angle but do converge at a point somewhere usually that point is not on the horizon but found on a line extended from but above the right VP.

@Boy she is simply showing how a VP may be found on a photograph.

[wizard509]

Not always easy to find VP'S on a photo it's more of a judgement call in my opinion, but she does have some good points that's why I posted this video.

[Egg Bramhill]

I thought this is an interesting explanation and hoped some might find it useful, VP's can be very complicated and not all are on the horizon for instance on a building with a pitched roof drawn in perspective the line of the nearest slope is not simply parallel to the slope angle of the furtherest slope angle but do converge at a point somewhere usually that point is not on the horizon but found on a line extended from but above the right VP.

Not following that Larry.

[handrawn]

not really clear to me either... but I think the point [pun intentional] may be that you can find points of convergence all over the place... which is what I was getting at with z-planes, excuse the animation jargon; but they are not vanishing points if they are not convergent on the horision, if they can be extended and still be within the field of view [though maybe hiding behind a bush ]

[wizard509]

I worked real hard on this reply both yesterday and today but try as I might I could not manage to create an example graphic of fanning.

[handrawn]

thanks Larry I understand the roof perspective - that is a point of convergence way up in the sky... that means you can still see beyond it, though you may need a telescope

I grant terminology varies, but to me that is not a 'true' vanishing point as you could have something constructed and visible beyond it after the lines cross - in this case that would not be practical in real life, but in a dawing you could do it - and if the point of convergence was ony feet above the ground you could it in real life, in sculpture for example... however that is only important if you are drawing to a horizon and not just contained within a z-plane [segment of the distance between you and the horizon]

as far as fanning goes are you thinking of something like this :

[wizard509]

thanks Larry I understand the roof perspective - that is a point of convergence way up in the sky... that means you can still see beyond it, though you may need a telescope

I grant terminology varies, but to me that is not a 'true' vanishing point as you could have something constructed and visible beyond it after the lines cross - in this case that would not be practical in real life, but in a dawing you could do it - and if the point of convergence was ony feet above the ground you could it in real life, in sculpture for example... however that is only important if you are drawing to a horizon and not just contained within a z-plane [segment of the distance between you and the horizon]

as far as fanning goes are you thinking of something like this :

Not quite but what you did works