Talk:3D projection

message: I do not understand the edits made by https://en.wikipedia.org/wiki/User:James_K_McMahon to the summary section in the following edit https://en.wikipedia.org/w/index.php?title=3D_projection&oldid=1000974026
- they seem to refer to a whole lot of stuff (particle effects, Lucasarts, US Patents to fabricate a cup) that is nothing to do with the subject. Vandalism?  — Preceding unsigned comment added by Tanoshimi (talk • contribs) 17:14, 8 February 2021 (UTC)
thread_title:  New Discussion 

message: Old discussion has been archived to: Talk:3D projection/Archive 1.
Stestagg 19:21, 11 September 2007 (UTC)
thread_title:  Old discussion 

message: I find the article about the perspective transform to be less than what one would hope for in present day Wiki. The topic is sufficiently complex as to warrant a 'gentle' introduction, with diagrams, and a mention of all the variations that one finds on the Net. For example, the description in: http://www.whisqu.se/per/docs/graphics91.htm derives a slightly different set of transform matrices. Since the topic is not intuitively obvious, the gently introduction can lead to an extensive article, in which homogeneous coordinates are clearly justified, the use of the rotational transformations explained, and I would suggest a numerical example. 
Per Bj. Bro (talk) 01:21, 2 January 2008 (UTC)
replies: text: I agree. I hope the current matrices are correct insofar as they do exactly the same as the non-matrix versions given. There definitely needs to be more explanation, and it also should be mentioned that there are many more possible representations than the variables chosen here. I also agree that a numerical example would help, and ideally it would be combined with a diagram - the current one doesn't really seem to fit the text. Also actual pictures of the result might help, but we should avoid overlap with perspective (graphical). --Allefant (talk) 12:37, 7 January 2008 (UTC)
thread_title:  Perspective transform 

message: *I propose moving the page from "3D projection" to "Planar Projection" as the page does not discuss all types of 3D projection. This way, the page can be placed more appropriately within the "Views" template.Kevmitch (talk) 13:20, 25 March 2008 (UTC)
replies: text: *Sounds good to me. --Allefant (talk) 13:38, 27 March 2008 (UTC)

text: *Hm, not much response so far. Myself, I guess the problem is deeper than just this one merger. One thing is overlap of different areas, like visual arts (Perspective (graphical)), math/linear algebra (Projection (linear algebra)), games (Top-down perspective), descriptive geometry... and then there's overlap within the topics itself, like "planar projection -> parallel projection -> orthographic projection -> axonometric projection -> isometric projection" - that's also bound to not really work out with one article for each level. So need to somehow work out a structure what topics should have how many articles here. And another problem is, no matter from which area you look at the topics, someone writing on them needs to be a bit of an expert in the field. Myself I came here from the article about isometric games... --Allefant (talk) 13:49, 14 April 2008 (UTC)

text: * Ok, so the main counter-argument, as I see it, to merging is quite subtle, but if this page were merged directly with Perspective/Orthographic Projection, there would be more of an argument for the content's complete removal, certainly people might call for the content to be made more terse, and less understandable for less-qualified mathematicians.  The Perspective projection page is already long, and deals with the issue from an art-history perspective.  A merger would broaden the scope of the article to the extent that some content from either article would, most likely, be [slowly] removed for the sake of article length.  —Preceding unsigned comment added by Stestagg (talk • contribs) 14:18, 14 May 2008 (UTC)

text: * Those who want to learn about perspectve from an art perspective is not interested in reading a lot of the math required to do the transformations, but you certainly are if do computer graphics or otherwise work with coordinate transformations, so these pages should not be merged, simply because they cover (should cover) different aspects of the topic.  —Preceding unsigned comment added by 129.177.20.38 (talk) 09:53, 16 June 2008 (UTC)

text: * I say no. This math theory is exactly what I was looking for, but would be out of place amongst art-history and non-math theory. I might not have found this information in another context. —AridWaste (talk) 22:18, 19 February 2010 (UTC)
thread_title:  Merger proposal 

message: Please post comments on the new lead image at Wikipedia:Graphic_Lab/Images_to_improve#3D projection. Thanks. Dhatfield (talk) 11:48, 28 June 2008 (UTC)
replies: text: I'm for removing the image or at least changing the caption, since that's plainly _not_  "A 3D perspective of an array of cubes".  Either those objects are not cubes or it's not a perspective projection. --Rubik's Cube (talk) 17:02, 1 July 2008 (UTC)

text: I removed the image, given the glaring inaccuracies in perspective, pending a discussion on this page. 81.152.21.117 (talk) 10:57, 5 July 2008 (UTC)

text: For reference, I've added a reference render created in Blender(software).  There are cubes in a 3d projection.  I set the 'focal-length' to a very low value to emphasise the 'perspective effect'.  For this reason, the image may look slightly different than might come from an optical camera, as most wide-angle camera lenses introduce significant barrel-distortion/fisheye. Stestagg (talk) 11:07, 5 July 2008 (UTC)
thread_title: New image

message: Why would we need to introduce a "vector d" that is exactly (1, 1) via matrix multiplication, when this vector then is multiplied by a diagonal matrix anyway? Is this some kind of mathematical joke? 129.27.12.17 (talk) 14:13, 20 April 2010 (UTC)
thread_title:  Temporal Vector d for (un)clarity 

message: I suggest to scrap the whole "Perspective projection" section, it's utterly useless and painful to the eye.  —Preceding unsigned comment added by Kallikanzarid (talk • contribs) 10:45, 17 November 2010 (UTC)
thread_title:  For mathematicians 

message: From the perspective of a game developer, I would never use the algorithm provided in the “Perspective Projection” section. Euler angles are a horrible way to store rotation; one typically represents that information using a matrix. If such is the case, one would simply multiply “a - c” by that single matrix to derive “d,” rather than calculating a rotation matrix for each Euler angle, which is an absurd waste of CPU cycles.
This approach, where it is assumed a rotation matrix is already associated with the camera, should be brought to the reader’s attention; I’ll do it myself if I get the chance. The only caveat is that 3D programming frameworks like Microsoft’s WPF typically store the camera’s backward-facing direction in the third row, whereas the modified algorithm would seem to expect the third row to provide the camera’s forward vector. (Requiring a simple negation.)
-- Premonition2035 (talk) 07:29, 22 January 2011 (UTC)
thread_title:  Game Development 

message: Sorry guys, I didn't make it past the first sentence, shouldn't "3D projection is any method of mapping three-dimensional points to a two-dimensional plane" read "3D projection is any method of mapping three-dimensional points from a two-dimensional plane"  — Preceding unsigned comment added by MrJosiahT (talk • contribs) 22:41, 22 August 2011 (UTC)
replies: text: I don't think so. I think it's correct as is. We are talking about projecting points from 3D. Since 2D points embedded in R3 are just in a 2D subspace, there's nothing for them to land on other than another 2D surface. For that operation—mapping 2D plane to 2D plane as though through 3D space—see homography. I'd be tempted to remove "plane" from "...to a two-dimensional plane" to allow for the case of projecting 3D points onto arbitrary 2D manifolds, but that's not what this article is about. —Ben FrantzDale (talk) 12:04, 23 August 2011 (UTC)
thread_title:  Mapping or projecting? 

message: But doesn't mention that human vision is 3d projection of light on the 2-dimensional plane of the eyeball.  http://www.mind.ilstu.edu/curriculum/vision_science_intro/vision_science_intro.php Vile-eight (talk) 17:32, 30 December 2016 (UTC)
replies: text: Eyeballs don't have any flat two-dimensional planes. They are curved. SharkD  Talk  20:15, 7 May 2017 (UTC)
thread_title:  Topic sentence focused on computer graphics 

message: I haven't looked closely at the math, but shouldn't we be comparing Perspective projection to Parallel projection instead of to Orthographic projection?  Otherwise you are totally ignoring Oblique projection. SharkD  Talk  20:17, 7 May 2017 (UTC)
thread_title:  Perspective vs Orthographic 

message: Sentences like "You can use that to do clipping techniques, replacing the variables with values of the point that's are out of the FOV-angle and the point inside Camera Matrix." are practically unintelligible. What is the "that" being used to perform clipping techniques? I was going to make an edit to remove the use of second-person grammar but I'm unsure how to preserve the original meaning of the text.  — Preceding unsigned comment added by Rjbranch (talk • contribs) 03:49, 5 August 2020 (UTC)
thread_title:  Text accompanying "Diagram" section is difficult to interpret