Talk:Orthographic projection

message: I added a disambiguation message to the top of the page and linked to Orthographic projection (geometry).  This article is wonderfully written, but I think it needs to be better disambiguated.  The material covered seems to be about drafting and engineering use of the term orthographic projection, but that is just one of the many meanings.  From searching online, I found at least three different, but related, meanings:
#Map projections
#Drawings (which is posted here)
#Transformation Matrices (which I put at Orthographic projection (geometry))
Let me know what you all think.
-- jaredwf 12:14, 12 May 2004 (UTC)
thread_title: DAB

message: "NOTE: The images displayed are reversed. Third angle symbol has view into cone on left and side view of cone length on right; First angle symbol is side view of cone length on left and view into cone on right. You are encouraged to cross reference with other sources until this image is fixed."
A very confusing note. What it means is that the images are mirror-images of the correct standard symbols, not that the FR and US labels are swapped. They do indeed show first and third angle projections correctly. (The mirror image of a first or third angle projection is itself a first or third angle projection, respectively.)
See this BBC page for a correct example: 
In particular, I find "view into cone" confusing because it seems to imply that you're looking into a hollow object, something like a waste bin on its side. But the object is actually a solid, and you're looking onto its truncated end.
In any case, the images should be fixed and the note removed.
--84.9.78.13 15:56, 4 March 2007 (UTC)
thread_title:  Standard Symbols 

message: Some mention should be made that orthographic projection is really a hypothetical form perspective projection—one where the camera lies an infinite distance away, and uses an infinite amount of zoom. Here are some links:  (sorry I couldn't come up with anything better). SharkD (talk) 19:33, 17 December 2007 (UTC)
replies: text: An animation is described here that shows a transition between normal and orthographic perspective. They may be talking about this. SharkD (talk) 03:26, 18 December 2007 (UTC)
replies: text: I created my own animation depicting this. It might be better suited for a Parallel Projection article, but I don't find the current one (a redirect) satisfactory. It's too math-related. The image really wouldn't be suitable for that article. SharkD (talk) 19:55, 2 January 2008 (UTC)
thread_title: Really a perspective projection

message: The article could really use an image showing quadrants I, II, III and IV, as well as H and V. I don't understand the text by itself. SharkD (talk) 19:53, 2 January 2008 (UTC)
replies: text: I figured it out and went ahead and created my own image. SharkD (talk) 21:28, 2 January 2008 (UTC)
thread_title: I don't understand the quadrant stuff

message: I suggest splitting the multi-view stuff into its own article, and reducing its presence in this article to a stub and link, like it is for Pictorials. SharkD (talk) 06:23, 15 November 2008 (UTC)
replies: text: I think that would indeed be more consistent to how the various projection articles are laid out right now. --Allefant (talk) 13:40, 15 November 2008 (UTC)
replies: text: OK, I split them into two articles. SharkD (talk) 02:05, 19 November 2008 (UTC)
thread_title: Suggest split

message: In mathematics, in particular linear algebra, orthographic projection of a single plane is called an affine transformation.  I didn't see any mention of affine transformations in the article so I linked this article to that one by adding a suitable clause to the lead.  --Vaughan Pratt (talk) 14:08, 12 December 2008 (UTC)
thread_title: Affine transformation

message: I found this article to be hard to understand. Perhaps another informative diagram or illustration on Orthographic projection would help? What about a rendering of a 3D model in orthographic projection, or an architectural drawing of an automobile. thinsmek 19:36, 20 January 2011 (UTC)
thread_title:  More diagrams? 

message: I was taught in an OSU class that pictorial projections are not a subcategory of orthogonal projections, but a distinct category. Why is the stuff about pictorials here?
--Robert the Devil  — Preceding unsigned comment added by 164.107.190.45 (talk) 00:17, 20 July 2012 (UTC)
replies: text: I just noticed this. I will fix the article. SharkD  Talk  06:33, 20 November 2015 (UTC)
thread_title: Classification

message: The Orthographic projection (geometry) and Orthographic projection (cartography) articles both cover subcategories of the subject of this main Orthographic projection article; the geometry article is about the geometry behind orthographic projection, while the cartography article is about the application of orthographic projection to cartography. All of these articles are quite short and, even if the subarticles were expanded, summaries of the subarticles should be included as sections in the main article. At present, however, the subarticles are so short that merging them here in their entirety would result in a reasonably sized article, therefore that seems to be the most preferable option. Neelix (talk) 16:22, 4 June 2014 (UTC)
replies: text: The cartography article isn’t “quite short” and will only expand. It’s also very different in emphasis. Other projections have cartographic-specific articles, and ought to: even the nomenclature of the mathematics differs entirely. It’s a different domain. Strebe (talk) 07:36, 5 June 2014 (UTC)
replies: text: Does that mean that you agree with the geometry article being merged here? Neelix (talk) 16:45, 5 June 2014 (UTC)
replies: text: No. The description in the Orthographic projection (geometry) article is in terms of linear algebra, which has nothing to do with the cartographic literature. Strebe (talk) 01:05, 6 June 2014 (UTC)
replies: text: I am not asking whether you think that Orthographic projection (geometry) should be merged into Orthographic projection (cartography), but rather whether you agree that Orthographic projection (geometry) should be merged into Orthographic projection. That issue is irrelevant to cartography. Neelix (talk) 15:36, 6 June 2014 (UTC)
replies: text: Sorry; I lost track of where “here” was when I responded. I’m less averse to merging Orthographic projection (geometry) into Orthographic projection. I’m not sure why they were ever separate, although it may be that, like cartography, geometry has its own specific emphasis, nomenclature, and significance for the projection. Strebe (talk) 04:54, 7 June 2014 (UTC)
thread_title:  Merger with [[Orthographic projection (geometry)]] and [[Orthographic projection (cartography)]] 

message: I think the History section should be removed from the article because it deals only with cartography, and is duplicated in Orthographic projection in cartography. Why write about it twice when it isn't even the main focus of this article? SharkD  Talk  03:57, 26 April 2017 (UTC)
replies: text: Apologies for letting this slip this long, SharkD. I agree it's troublesome to duplicate the information from the cartography-specific article. People may well want to know the origins and etymology, though, so perhaps we should direct them to the cartography page in the History section? Other ideas? Strebe (talk) 17:45, 8 May 2017 (UTC)
replies: text: I will just move 'History' to a sub-section of 'Cartography' I guess. SharkD  Talk  02:58, 9 May 2017 (UTC)
thread_title:  History section 

message: Regarding this edit: The term axonometry, and hence axonometric projection, was coined in Germany and still retains its original meaning in European text books. It is worth noting in the article. See the discussion here. The fact that this is English language Wikipedia doesn't mean we can't talk about non-English language topics. ➧datumizer  ☎  21:09, 6 June 2019 (UTC)
replies: text: The text you inserted is, “(in English language regions)”. It’s nothing about German or European locales and nothing about why you’re inserting this parenthetical. The literal meaning of your parenthetical is, The term for this in English is “axonometric projection”, which, in an English encyclopædia is redundant and looks utterly out of place. It would be the same as saying, A baked confection based primarily on flour and eggs and sugar is called a “cake” (in English language regions). If you are trying to say something else, then please find a way to say it that is intelligible to readers who really have no idea what you’re getting at. Strebe (talk) 21:51, 6 June 2019 (UTC)
thread_title:  Parenthetical 

message: The article mentions that:
"The inversion of the projection matrix P−1, which can be used as the unprojection matrix is defined: ...".
According to https://math.stackexchange.com/a/311353 , a projection matrix should have no inverse (as you effectively lose one dimension's information in the process). Therefore, either I did not understand this line correctly or this line is wrong. Either way, I think that it should be clarified or removed.
Donaldrunk (talk) 09:16, 29 March 2020 (UTC)
replies: text: "The inverses of two projection matrices can be used to regenerate the object location matrix." ? --Turbojet (talk) 11:56, 20 March 2021 (UTC)
thread_title:  Inverse matrix of an orthographic projection 

message: Please provide more background as you introduce the matrix at the start of the geometry section. What are the row and column coordinates of that first matrix? Thanks! --Lbeaumont (talk) 11:40, 23 August 2021 (UTC)
thread_title:  Say more to introduce the matrix at the beginning of the geometry section.