"the picture plane"

[jctgf]

hi,
what would you understand from a chapter title like this, please? the context is a drawing book.
thanks.

[jlinger]

A flat surface (plane) on which to draw?

[abaka]

hi,
what would you understand from a chapter title like this, please? the context is a drawing book.
thanks.

That's a technical term, not strictly an English idiom.

A picture (painting, photograph, projected movie image or image in the back of one eye) is a two-dimensional projection of a three-dimensional real scene.

If the picture is flat, it is mathematically a plane. Look at a scene directly; put a flat screen perpendicular to your line of sight in front of what you're looking at; and put each object in the scene on the screen exactly where the line between the object and your eye intersects the screen. Thus you've drawn a picture on the screen, i.e. the picture frame.

[jctgf]

A flat surface (plane) on which to draw?

Precisely! I had never seen the word ''plane'' being used in such a way. Is it common and natural, please? Are there more expressions or situations in which we employ the word ''plane'' to mean "flat"?
Thanks!

[jctgf]

That's a technical term, not strictly an English idiom.

A picture (painting, photograph, projected movie image or image in the back of one eye) is a two-dimensional projection of a three-dimensional real scene.

If the picture is flat, it is mathematically a plane. Look at a scene directly; put a flat screen perpendicular to your line of sight in front of what you're looking at; and put each object in the scene on the screen exactly where the line between the object and your eye intersects the screen. Thus you've drawn a picture on the screen, i.e. the picture frame.

that's exactly what a "picture plane" is all about, according to the book.

[abaka]

"Plane" in this sense is a perfectly flat surface. As a noun, it is rarely used non-scientifically or non-technically in this original meaning.

But it can be used as a verb:

To plane the wood.

Metaphorically, "plane" means a state of existence.

On a higher plane = more abstractly.

The astral plane = the universe of all souls, in a spiritual sense.

"Plane" is, of course, also a common short form for "airplane".