POV-Ray : Newsgroups : povray.advanced-users : Converting 2D screen coordinates to 3D : Re: Converting 2D screen coordinates to 3D Server Time
26 Mar 2023 05:34:31 EDT (-0400)
  Re: Converting 2D screen coordinates to 3D  
From: Kenneth
Date: 6 Feb 2023 08:15:00
Message: <web.63e0fc80ef540dd79b4924336e066e29@news.povray.org>
A couple of initial (naive?) questions, to help me better-visualize the details:
> Assume an orthographic camera.
> Let's say that I have a line segment extending from the top left of
> an image to the lower right.

Is that initial line an actual object in the 3-D scene that appears to extend
from corner to corner, or is it a line only in flat 2-D screen space (like
Screen.inc would typically produce, for example)? I'm guessing it's a 3-D
object, extending into the scene.

> If I draw a line perpendicular to this, then I can use this
> new line as an axis for rotation.

Perpendicular to it in x/y screen space, or pointing 'out' from the middle of
the initial line segment directly into the camera? Or maybe pointing somewhere
else in 3-D space? Sorry, this one is hard to visualize.
> If I rotate a copy of the line segment around this axis, it should visually
> remain in line with the original line segment, but the ends would appear to
> contract.

I can sort of 'see' this...depending on whether or not I understand the initial

Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.