Talk:POV-Ray

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[edit] Talk

If the source is freely available, and there are codeforks, how is not open source? Perhaps it should read "The software is open source under the terms of the POV-Ray license"? --cprompt

Probably because the POV-Ray License says it is not open source. Don't want to get into legal entanglements :) In short they say it is not open source because when it was first developed, it was done so under a non-OSS license (since the GPL was virtually unheard of at the time), and it would be unfair to those who contributed to the code to go changing the license now. -- Wapcaplet
Fair enough.
--cprompt


Some remarks:

"A Turing-complete C-like scene description language ..."

POV SDL is not C-like. It has nothing of the typical C-like features. The syntax of for example #while and #if conditionals is quite different. And don't be fooled by the #include statement, it has nothing to do with a pre-processeor. I would just leave out the "C-like" in the quoted line.

On at least two occasions POV-Ray is referred to a modeller. Although with the addition of macros, functions and loops it has gained better tools for making models, POV-Ray is still "only" a render engine. This may be also be the cause of some errors in the 'primitive' chapter

Regarding the last paragraph of the primitive section. " The primitive system in POV-Ray also has a number of weaknesses. For example, objects which cannot be accurately described by the geometric primitives present in POV-Ray must be approximated using a mesh of polygons."

If it couldn't handle the triangle primitive or the mesh object, one couldn't make these objects at all. So I don't see the availability of mesh as a weakness.

" POV-Ray is not as well-equipped as some other rendering software to handle complex objects with many polygons."

Actually it is a lot better at that than many other rendering tools. One can declare a mesh once and then instantiate it many times without using much more memory. The meshes used can be as big as the amount of RAM in a machine permits.

" "Bending" of objects in POV-Ray cannot be done without resorting to exotic techniques, such as tesselation"

Bending is not a rendering but a modelling feature (altough it could be done with curved light rays). Yet some objects are 'bendable', like isosurfaces, bicubic_patches but it takes some heavy scripting.

I'd just leave out this whole paragraph.

Well, the SDL resembles C. Someone familiar with reading C code would have little trouble interpreting POV-Ray SDL. Feel free to take it out, or rephrase it.
I don't see where POV-Ray is actually called a modeller. Modelling is mentioned in the context of CSG; POV-Ray is compared with "other modelling software", which could probably be better explained; you're right in pointing out that there is often some confusion about the difference between a modeller and a renderer. Believe it or not, I had a university professor, whose specialization was computer graphics, who did not grasp this distinction; he said on several occasions that the three kinds of "modelling" were "polygonal, raytracing, and radiosity." I took an entire graphics course from this guy :-)
Anyway, I agree with many of the points you make here. That whole section is pretty vague and could use some clarification; please feel free to rewrite it!
-- Wapcaplet 19:31, 22 Aug 2003 (UTC)

--

Is it proper to signify all the trademarks in this article with "tm" ? Wikipedia doesn't seem to have a policy on this, but from what I understood of the Trademark article, "tm" is primarily supposed to appear in material produced by the trademark owner. It doesn't seem proper for an encyclopedia. I haven't removed the "tm"s (not wanting to start an edit war ;-) but I believe they should go.--Ejrh

I agree, I was never really comfortable with having them in there either. -- Wapcaplet 16:14, 26 Jan 2004 (UTC)

Ok... I can't resist.... shouldn't this article be banned for inherrantly not being NPOV? Running away fast..... - UtherSRG 16:25, 26 Jan 2004 (UTC)

This sounds like a weapon that destroys otherwise well-written Wikipedia articles =D Ed Cormany
I agree. I think we should move this article to NPOV-Ray immediately. -- Wapcaplet 18:14, 27 Jan 2004 (UTC)

I'm not sure why there's so much confusion about the licensing of POV-Ray. Why does it have to be connected to the GPL in any way? I think instead of making such unclear statements in the article as "While the programs source is in the open, it cannot be redistributed(?)" (complete with question mark), or "not sure if that means GPL or not...", it'd be better to leave them out entirely. POV-Ray is licensed under the POV-Ray License. Nuff said. Leave it to the articles on open source and free software to explain the nuances. I don't fully understand the POV-Ray license myself, but we shouldn't try to explain it if we don't understand it :-) -- Wapcaplet 22:08, 27 Mar 2004 (UTC)

Even the POVray folks themselves say it's not Open Source - the legal document attached with the release has a section entitled "WHY ISN'T POV-RAY OPEN SOURCE ?" and goes on to say "While the POV-Ray™ source code is freely available, it isn't 'open' according to the currently popular definition of the term (meaning that it isn't available to create derivative works).". So User: Paullusmagnus' restoration of the "not open source" sentence was correct. -- Finlay McWalter | Talk 13:10, 24 Apr 2004 (UTC)

I am not really comfortable with the sentence "POV-Ray is freeware, and although the source code is available for modification, it is not considered open source by most people." There's not really any room for opinion on the issue; POV-Ray is not open source. The authors of the software and its license say it is not, and they are the only authority on the issue. The reference given for the sentence in question is taken straight from the POV-Ray license. I am changing the sentence to reflect this. If we must relate the license to open source in some way, we should at least be clear on matters of fact. -- Wapcaplet 01:15, 25 Apr 2004 (UTC)

On further reflection, using the definition "open source software is any software whose source is available", POV-Ray could be considered open source. The POV-Ray License is not, however, an open-source license. -- Wapcaplet 01:20, 25 Apr 2004 (UTC)
The term "open source", as applied to software, was invented by Christine Peterson in 1998, and popularized by the Open Source Initiative in the ensuing years, as a substitute for the term "free software", to refer to software whose users have a specific set of freedoms, including the freedom to create derived works; in the few weeks after the term was invented, they edited the Debian Free Software Guidelines slightly to create the Open Source Definition. The term has been consistently used by a broad open-source community during the eight years since then to refer to specifically the meaning defined in the OSD. Please don't spread confusion by inventing your own subtly-different definitions for the term, such as "any software whose source is available". It would be great if POV-Ray were open source, and maybe some day it will be, but neither the open-source community nor the POV-Ray team is currently trying to confuse the issue by claiming that POV-Ray is open-source. Kragen Sitaker 19:03, 6 December 2006 (UTC)
using the definition "open source software is any software whose source is available", Windows could be considered open source. http://www.microsoft.com/resources/sharedsource/licensing/default.mspx --anon 01:27, 13 September 2006 (UTC)
According to that page, Microsoft source is available to participants in the programs listed. Povray source is available to all. —Tamfang 06:24, 17 September 2006 (UTC)

Would be nice to show some samples of photo-realistic work on this page. There are some great ones out there, and the photo-realistic stuff is what wow's people the most if they are new to raytracing. 62.253.128.12 19:43, 22 August 2005 (UTC)

I just added a such a picture to the page --Gilles Tran 15:52, 26 January 2006 (UTC)

[edit] External links

I thought it quite ironically amusing that an article about POV-Ray should have so much "POV" in it! I just cleaned out a lot of the blatant unbalanced praise that was in there (including of my favourite POV-er of all time, so I'm not being mean) but I'm still not sure if the current state is appropriate. WP:NOT a repository of links; so what criteria makes an artist notable enough to appear on here? Maybe artists featured on the POV-Ray hall of fame? Perhaps even no artists at all, and focus on links to artist directories. I don't know at the moment... comments? BigBlueFish 19:22, 5 April 2006 (UTC)

Keep all external links. I'm not going to make a long-winded argument in support; just in general, for any piece of software, I want to see the longest list of external links. Biased or whatever, I don't care -- I'll make my judgements when I get there. At minimum, move all links rm from article to a list. John Reid 21:47, 15 October 2006 (UTC)

[edit] Change the infobox image?

I think we should change the image in the infobox to glasses (from teapot). Indeed I think we should remove teapot from here altogether - it's only here because at the time this article didn't have an image. It isn't, and never was, a representative example of what POV-Ray can be used for. -- Finlay McWalter | Talk 20:37, 5 April 2006 (UTC)

I don't think it would be an objective ideal. The glasses still life has a somewhat artistic expression to it, whereas a representative image should be a neutral demonstration. However the teapot doesn't demonstrate much reflection or refraction. Maybe somebody could make a new example (in a while I might try if nobody does, but I'm useless at POV-ray) with, perhaps, three spheres on the ubiquitous checkered plane, one glass, one chrome and one coloured to demonstrate reflection, refraction and radiosity. A Utah Teapot with a glass spout might not have the same effect! BigBlueFish 13:20, 6 April 2006 (UTC)
When I added the infobox I used the teapot image because it was the first one in the article, not because of any representation. I can make a new image if the teapot falls out of favour (the spheres seem simple enough). Shen 19:28, 6 April 2006 (UTC)
I am dismayed to see that there is no shiny sphere over a checkered plane. I'll get on it any month now. —Tamfang 05:23, 13 April 2006 (UTC)
be sure that it has some HDRI applied to it. it's the latest fad... :P namekuseijin at gmail.com 3 April 2006

[edit] SDL info

I've seen a lot of links for POV-Ray in the reference section. I'm interested in SDL since a user named it in shading language talk page but I cannot affort wandering thuru all of them to find the needed information. Could you please point out a few 'best of' links about SDL for me? Thank you,
MaxDZ8 talk 06:47, 26 July 2006 (UTC)

[edit] Why is this in Category:Free graphics software, when it isn't Free?

The category describes itself thus:

This is a category of articles relating to software which can be freely used, copied, studied, modified, and redistributed by everyone that obtains a copy: "free software" or "open source software". Typically, this means software which is distributed with a free software license, and whose source code is available to anyone who receives a copy of the software.

POV-Ray: a) Cannot be freely copied, modified or redistributed: it has 'distribute xor modify' restrictions like Pine has, and has many additional restrictions on both distribution and modification, any one of which would be non-free. Clause 1.3 of the modification license (the only clause that grants permission to modify), alone, is sufficient to contradict the category's requirements that the software be freely modifiable (I reordered the clauses for a more sequencial read):

 1.3. Subject to this clause 1.3 and the balance of this clause 1, you are 
      granted the privilege to modify and compile the source code of the 
      Licensed Version for your own personal use if such modification 
      fulfils one or more purposes set out in clause 1.1. 

 1.1. The source code of  POV-Ray is provided to: promote the porting of 
      POV-Ray to hardware and operating systems which POV does not support; 
      promote experimentation and development of new features to the core 
      code which might eventually be incorporated into the official version; 
      and provide insight into the inner workings of the program for 
      educational purposes.

 1.2. Except as expressly set out in this agreement, or permitted by another 
      agreement between you and POV, any use or modification of any POV-Ray 
      source code is expressly prohibited.

b) Is not '"free software" or "open source software"', by the developers' admision in their own license document --anon 01:27, 13 September 2006 (UTC)

The povray article explains the restrictions, as well as the historical reasons for them. IMHO it is close enough to the definition of free software to merit inclusion (and excluding it from the catagory would, IMHO, be the greater sin). It might be better to slightly re-word the category to allow a little flexibility. Tomandlu 09:55, 13 September 2006 (UTC)
Possibly instead there should be a category/the category 'free graphics software' should be renamed to "gratis graphics software" (and any other gratis graphics software that isn't free be added to it)? Massaging the definition so that one particular piece of non-free software can be fitted into it seems dishonest.
On a personal note, I'm not convinced that 'free enough software' is a good thing. Gratis software with interesting restrictions provides the same barrier to entry for a newcomer that an established free project does, but without contributing back in the same way that a free project would. http://www.asty.org/articles/20010702pine.html elaborates on this somewhat.
Finally, could you confirm that povray is actually attempting to become free? The explaination is gone from the latest license statements, and there is rumbling that the povray team is actually rather attached to their no-fork, no-commercial, no-embedding clauses. (http://lists.debian.org/debian-devel/2005/02/msg00509.html ). Further circumstancial evidence for the prosecution: POV-Ray has been 'wanting to relicense' since December 2001, and yet in nearly five years, nothing has happened. The statement of the developer's intention to relicense under a Free license was taken out of the license document in June 2004 ( http://web.archive.org/web/20040612152311/http://www.povray.org/povlegal.html ) --anon 13:15, 13 September 2006 (UTC)
Well, I can't comment on the developers current intentions - however, the delay (given that a change in the licence terms will require a full rewrite of the source) is understandable.
As for the "contributing back" stuff - it's not worked that way for pov - overloading and adding new functionality to pov has always been possible without modifying pov's source (e.g. megapov), and many of the advances in pov have come about through these means (e.g. the inclusion of iso-surfaces in pov came from code originally in megapov).
I was thinking of "contributing back to the community": while people can put their stuff into POV, they can't put POV's stuff into their projects. --anon 13:52, 14 September 2006 (UTC)
I have to admit to some sympathy with the "no-fork, etc." view, but that's another matter... Tomandlu 13:37, 13 September 2006 (UTC)
I see nothing on the page that formally disqualifies POV-Ray from being listed there. To clarify: the POV-Ray license allows copying, studying, modification and redistribution. Whether the restrictions imposed by the POV-Ray license (restrictions like they also exist in other free software licenses) are a reason to not call it free is subject to interpretation. The excerpts you cited from the license are not sufficient to form a qualified opinion on this though. There is no no-fork clause (see MegaPOV - http://megapov.inetart.net/) and no no-commercial clause (the word 'commercial' or equivalent terms do not occur in the current license). The POV-Ray article is perfectly clear on this and does IMO in no way try to mislead the reader about the fact that and why POV-Ray is not open source according to the OSI definition. The Free graphics software page IMO does well in not forcing a certain interpretation here.
no-fork clause: "all Modified Versions that you create must, in substance, be modifications of the Licensed Version." (http://www.povray.org/source-license.html). This means that while you can fork POVRay, this is where it ends. No other entity can build on your code.
no-commercial clause: "4.3 Where the making, or the provision, of a copy of the Software is authorised under the terms of clause 3 but not under those of clause 2 of this agreement, the total of all fees charged in relation to such making or provision and including all fees (including shipping and handling fees) which are charged in respect of any software, hardware or other material provided in conjunction with or in any manner which is reasonably connected with the making, or the provision, of a copy of the Software must not exceed the reasonable costs incurred by the Distributor in making the reproduction, or in the provision, of that copy for which the fee is charged. " (http://www.povray.org/distribution-license.html)
You apparently completely misunderstand the parts of the license you are quoting. I hate to repeat myself but there is no no-fork and no no-commercial clause in the license. The various unofficial versions (see the POV-Ray article for links) are the best proof for the lack of a no-fork clause. POV-Ray has been used extensively for commercial purposes and i have done paid work in modifying and extending POV-Ray myself and know others who have done the same. The claim the POV-Ray license forbids this or that the POV-Team has an interest not to allow this is frivolous. The purpose of the section you quoted is to avoid disguising of the fact that POV-Ray is free. You may of course not like this and refrain from using POV-Ray because of this but it would be quite questionable to remove POV-Ray from Category:Free_graphics_software and thereby force your opinion on others. Since the licensing is prominently discussed in the POV-Ray article it is unlikely that a reader coming through the category page is deceived concerning the licensing situation. Imagico 17:44, 14 September 2006 (UTC)
It is my belief that POV's licence, regardless of whether or not it is Free Software, is contradictory to the criteria for inclusion in Category:Free Graphics Software, as described by the page itself. As you feel strongly that POV belongs in this category, please address the concerns I describe immediately below. -- [User:anon|anon]] 23:17, 14 September 2006 (UTC)
I already did so: "I see nothing on the Category:Free_graphics_software page that formally disqualifies POV-Ray from being listed there.". Furthermore: "Whether the restrictions imposed by the POV-Ray license (restrictions like they also exist in other free software licenses) are a reason to not call it free is subject to interpretation.". Remember that Wikipedia should maintain a Wikipedia:Neutral_point_of_view - it is inappropriate for a category page to only include items that fall into this category according to your (or the FSF) definition of it. Imagico 06:15, 15 September 2006 (UTC)
Let me amend that to 'please address these specific concerns, using something other than proof by repeated assertion '. While you say you can see nothing on Category:Free_graphics_software, I can see that it requires that the listed software be freely modifiable (POV-Ray isn't), and freely redistributable by everyone that obtains a copy (POV-Ray isn't). I've gone into specifics before; please address them.
From my point of view it is absolutely clear from the statements i made and repeated what i mean. But i try to be even more specific. Nearly all Programs listed in Category:Free_graphics_software (maybe with the exception of those in Public Domain or under some variants of the BSD license) have restrictions imposed to the right of redistribution. The GPL for example has them in section 2, for example 2.b) "You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License." - see http://www.gnu.org/copyleft/gpl.html. Other licenses have other restrictions (like for example related to software patents owned by the one who redistributes etc.). And as said: "Whether the restrictions imposed by the POV-Ray license ... are a reason to not call it free is subject to interpretation.". The description on Category:Free graphics software does not draw a line which restrictions disqualify a software to be listed there and neither would it be compatible with the spirit of Wikipedia to draw such a line based on an arbitrary interpretation. Imagico 17:30, 15 September 2006 (UTC)
Please show me either an interpretation of Category:Free_graphics_software's description that allows POV-Ray's license (I'm not even sure if the lax interpretation I came up with for sake of argument would permit POVRay (It still requires allowing redistribution by anyone that receives a copy, which is a right not granted to anyone on POV's Revocation List (http://www.povray.org/distribution-license.html, section 4.4) ). ), or an interpretation of POV-Ray's license that is compatible with the discription given by Category:Free_graphics_software (be sure to address the following concerns: the Revocation List hindering redistribution, the inability to convert POV-Ray into a library hindering modification, and the inability to bundle POV-Ray with non-software goods hindering redistribution. If you're feeling keen, you might also want to tackle the various things you can't put on the same CD). Alternatively, re-word Category:Free_graphics_software to allow things that are 'free software' by your definition. -- [User:anon|anon]] 16:00, 15 September 2006 (UTC)
The only way the various licenses are consistent with Category:Free Graphics Software, is if you interpret its description thusly: "This is a category of articles relating to software which can be (freely used), copied, studied, modified, and (redistributed by everyone that obtains a copy)" (and ignore the phrase ":free software" or "open source software").
If you read it in any other way, for example, "This is a category of articles relating to software which can be (freely (used, copied, studied, modified, and redistributed) by everyone that obtains a copy)", it's clear that POV does not fit this definition. That it may not be freely modified (you can't, for instance, modify it into a library for Blender, or make it behave in an incompatible way to the original) is sufficient to disqualify it, but in addition it cannot be freely redistributed (for example, it can't be distributed as part of a Live CD, unless you're a "generally recognised Distribution of a recognised operating system", and it can't be stuck on a coverdisk (4.1. Nothing in this agreement gives the Distributor: (c) any right to bundle a copy of the Software ... with any other items, including books and magazines.) ). --anon 13:52, 14 September 2006 (UTC)
There is absolutely no reason to assume the plans of the POV-Team concerning the licensing of a rewrite of POV-Ray have changed - as can easily be seen from public statements in the POV-Ray Newsgroups (http://news.povray.org/povray.general/message/%3C4152dfb1%40news.povray.org%3E/#%3C4152dfb1%40news.povray.org%3E). Note there was never the intention to relicense the current POV-Ray source code as it is clearly said in the 3.5 license:
 Therefore, POV- Ray[tm] will remain on this  existing
 license until we  do a full  re-write (which is  intended for v4),  at
 which time a new license will  be instituted that is far more  liberal
 in terms of reuse.
which was removed from the license simply because it does not belong there. Parts of the considerable efforts to clarify the origin of the different parts of the POV-Ray source code are documented on http://www.povray.org/sch/. It is usually more reliable to look for first hand information on such matter on the POV-Ray newsgroups and website than in the wild guesses posted in some debian mailing list... :-)
Thankyou for doing this research. To paraphrase Chris Tarrant, 'It's only easy to find when you know where to look'. Interestingly, the post you link states: "POV-Ray version 4.0 will be under a different license. Yes, we will have replaced the parts of the source that we cannot re-license.". Have they maybe changed their mind about rewriting from scratch? --anon 13:52, 14 September 2006 (UTC)
Conjecture: The parts that do not need replacing were written by identifiable people who have consented to the relicensing. —Tamfang 06:29, 17 September 2006 (UTC)
And please read Wikipedia:Sign_your_posts_on_talk_pages. Imagico 21:08, 13 September 2006 (UTC)
Done. --anon 13:52, 14 September 2006 (UTC)
I wonder since when has "free" become a synonym for "distributed under an OSI-compliant open source license". For example Word Viewer by Microsoft is free but not open source. Opera is free but not open source (iirc). You don't have to pay anything to use them: They are free. I think that the FSF has hijacked the word "free" in relation to software and given it a much stricter meaning than it really has, and everybody seems to have gone in the same bandwagon. Wopr 23:10, 13 September 2006 (UTC)
You're confusing the terms 'free', and 'free software'. Opera is free (gratis);, Seamonkey is free software. I think the blame for establishing the term 'free software' can be divided evenly between the FSF and Debian. --anon 13:52, 14 September 2006 (UTC).
It's very unreasonable to take a word pair which has a very common and logical meaning , give it a much more restricted meaning and then expect people to not to get confused. There's absolutely nothing wrong in this kind of thinking: "It's software. It's free. Thus it is free software." You can't just go and arbitrarily change the meaning of commonly used words and then expect everybody to obey that new meaning. If the FSF wanted a unique non-confusing term for what they now call "free software", they should have used something a lot more unambiguous. Wopr 18:38, 14 September 2006 (UTC)
The term 'free software' does not need to be established - it is a natural english language term formed by the adjective free and the noun software. The fact that the FSF is using the term with a very special meaning does not devaluate other meanings. See also free software (disambiguation). Imagico 17:44, 14 September 2006 (UTC)
The term 'software' does not need to be established - it is a natural english language term formed by the adjective soft and the noun ware. Just because everyone else is using the term with a very special meaning does not devaluate the 'manufactured stuff that isn't hard' interpretation. --anon 16:00, 15 September 2006 (UTC)
Your sarcasm is rather invalid. "Soft ware" is in no way a commonly-used term to refer to anything. Also, even if someone got confused about the meaning of the word "software", it would be about something completely unrelated to computers and thus there's no real confusion there. What I mean that it's not very likely that someone says "this is not software" and someone else says "yes it is" because that just doesn't make any sense. Even if some kind of confusion would happen with the term "software", it's innocuous. However, the situation is rather different with "free software": If someone says "this is not free software" from a software which can be used for free, then a rather relevant confusion is likely to happen: People might think that it is a commercial software which you have to pay for. Thus it completely reverses the meaning of "free". Also, unlike with "software", which is very rare to cause confusion, using a different meaning for "free software" than what people intuitively think is very likely to cause confusion. The problem is thus much more relevant in the latter case. Wopr 14:47, 17 September 2006 (UTC)

[edit] nonfeatures

User:Arnero's latest edit is a list of features that Povray doesn't have — "Not featured but suitable for a ray tracer". I changed the introduction line to make it marginally relevant here, but it might be more appropriate to remove the list and put it in a more general article on ray tracing. —Tamfang 20:05, 30 October 2006 (UTC)

Probaby this is the same person that turned up on the POV-Ray newsgroups quite recently wanting to know if a similar set of features to those he's added to the article were available, as he wished to use the programme for optical design. POV-Ray is not an optical design simulator but a ray-tracing renderer. Both may involve the use of raytracing but they have different requirements and outputs. You may notice that he's also added "lasing" to the list of features. POV-Ray does not simulate lasing in a way that would be accepted in an optical design simulator, it was never meant for that.

I've removed lasing outright from the feature list, and I copy the "missing features" section here for convenience in case anyone wants to move it to the raytracing article:-

POV-Ray does not have any of the following features which might be found in a more advanced ray tracer:

217.155.197.228 16:15, 4 November 2006 (UTC)

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