Hello all,
The is a follow up to my reply to Dean Jackson's message from October
last year [1]. In my reply, I said the below:
| The illustration and assumed eye position is
| misleading because none of this is really happening
| because every thing is relative and somewhat anchored
| to the veiwport or z plane. We only trick the viewer
| into believing that they are positioned in 3D space
| as a painting on some wall does.
What I mean by the above is that what is really happening is the
vanishing point or point of perspective is behind the drawing surface or
picture plane [2] and not in front of it unless the value (must always
be positive) for the Z axis is greater than the value for perspective
(e.g. 'translateZ: 600px' together with 'perspective: 400px').
I have attached a graphic (perspective_distance-b.png) demonstrating
this more correct way of visualizing where the vanishing point is in
respect to drawing surface which is very different to the Figure 3 in
section 6.1 of CSS Transforms [3]. Below is a interactive demo (working
correctly in Firefox and IE12).
http://css-class.com/test/css/3/perspective/depth-of-field.htm
1. http://lists.w3.org/Archives/Public/public-fx/2013OctDec/0002.html
2. http://en.wikipedia.org/wiki/Picture_plane
2. http://dev.w3.org/csswg/css-transforms/#3d-transform-rendering
Alan
--
Alan Gresley
http://css-3d.org/
http://css-class.com/
