POV-Ray : Newsgroups : povray.documentation.inbuilt : Orientation and left handed frame Server Time
6 Jul 2022 00:14:30 EDT (-0400)
  Orientation and left handed frame (Message 11 to 19 of 19)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Jim Holsenback
Subject: Re: Orientation and left handed frame
Date: 7 Oct 2016 11:35:25
Message: <57f7c0bd$1@news.povray.org>
On 10/7/2016 11:08 AM, lelama wrote:
>  If this is confusing for some people, let's keep the old formulation. 
But if
> it's not confusing, it would be more clear for people who wander whether it is
> possible to play independtly with the coordinate system and the rotations, and
> to people who want to know what may be changed with options.

i think you're making this /more/ complicated then it needs to be ... 
experience with the rules of working with coordinates (regardless of 
left or right handiness) is a most basic concept as noted in post from 
Le_Forgeron


Post a reply to this message

From: clipka
Subject: Re: Orientation and left handed frame
Date: 7 Oct 2016 12:38:19
Message: <57f7cf7b$1@news.povray.org>
Am 07.10.2016 um 17:08 schrieb lelama:
> 
> After this discussion, I come with a question:
> 
> 
> I was thinking about replacing the folloing sentence in the documentation :
> 
> 
>     "In a right-handed system we use our right hand for the "Aerobics"."
> 
> 
> By the following:
> 
> 
>     When a right-handed system is used in Pov-Ray,  we use our right hand
>     for the "Aerobics", both for the coordinate system
>    and for the rotations.

I second this change...

>     A rotation of 90 degrees around the vector +X sends the vector +Y
>    to the vector +Z, in any system, left handed or right handed.

... but this sentence is both redundant and, for that section of the
docs, overly technical...

>    There is no option to change this behaviour.

... and this is information most members of that section's target
audience won't care about.

Remember that there is such a thing as too much information; people need
to be able to digest the package of information we provide them with,
and this section is part of the docs intended for people who aren't
accustomed to heavy meals.

I guess the reference section about rotations would be a more suitable
place to go into technical details.


Post a reply to this message

From: Bald Eagle
Subject: Re: Orientation and left handed frame
Date: 7 Oct 2016 12:40:00
Message: <web.57f7ceb5844df073b488d9aa0@news.povray.org>
Jim Holsenback <spa### [at] nothanksnet> wrote:

> i think you're making this /more/ complicated then it needs to be ...
> experience with the rules of working with coordinates (regardless of
> left or right handiness) is a most basic concept as noted in post from
> Le_Forgeron

Right - anyone who deals with chiral spaces learns whatever convention is used
for that system.

There is a "Right-hand rule" for physics (electromagnetism), engineering, math,
architecture, etc.

The left hand rule for POV-ray ought to be just as straightforward.

*** Point the left thumb in the +axis direction, curl the fingers, and that's
the positive direction of rotation.   ***

A picture or two may be a nice addition, but I don't think anything needs to be
added to the text or changed.


Post a reply to this message

From: Jim Holsenback
Subject: Re: Orientation and left handed frame
Date: 7 Oct 2016 13:58:38
Message: <57f7e24e$1@news.povray.org>
On 10/7/2016 12:38 PM, clipka wrote:
> I second this change...

done: 
http://wiki.povray.org/content/Documentation:Tutorial_Section_2#Understanding_POV-Ray.27s_Coordinate_System

3rd paragraph after the image


Post a reply to this message

From: omniverse
Subject: Re: Orientation and left handed frame
Date: 7 Oct 2016 15:40:01
Message: <web.57f7f940844df073b1933f770@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> Jim Holsenback <spa### [at] nothanksnet> wrote:
>
> > i think you're making this /more/ complicated then it needs to be ...
>
> *** Point the left thumb in the +axis direction, curl the fingers, and that's
> the positive direction of rotation.   ***
>
> A picture or two may be a nice addition, but I don't think anything needs to be
> added to the text or changed.

I was getting a look at the camera 'right' being negative and using a viewpoint
from +z as was mentioned here.

So for any curious people I posted a couple animations showing the difference
from the more typical positive right and -z camera location.

http://news.povray.org/povray.binaries.animations/thread/%3Cweb.57f7f2f38d36d3bfb1933f770%40news.povray.org%3E/


Post a reply to this message

From: Christian Froeschlin
Subject: Re: Orientation and left handed frame
Date: 15 Oct 2016 18:57:09
Message: <5802b445$1@news.povray.org>
On 07.10.2016 19:58, Jim Holsenback wrote:
>
> 3rd paragraph after the image

A minor thing that struck me about the page layout:

I see two images in a row with a paragraph of text between them

   [Image: LH coord sys] [text about LHS] [Image: Aerobics]

   followed by text about rotation / curling / aerobics

The text about LHS refers to positioning left hand fingers
to match coordinate system which is confusing since it is placed
next to the image showing an entirely different hand position.

Maybe as a quick hack it could be rearranged to

   [Image: LH coord sys] [text about LHS]

   [Image: Aerobics] [text about rotation / curling / aerobics]

It may also lead to a bit more pleasing layout as the narrow
paragraph between two images looks a bit odd to me anyway.


Post a reply to this message

From: Jim Holsenback
Subject: Re: Orientation and left handed frame
Date: 16 Oct 2016 09:59:36
Message: <580387c8$1@news.povray.org>
On 10/15/2016 6:57 PM, Christian Froeschlin wrote:
> It may also lead to a bit more pleasing layout as the narrow
> paragraph between two images looks a bit odd to me anyway.

http://wiki.povray.org/content/Documentation:Tutorial_Section_2#Understanding_POV-Ray.27s_Coordinate_System


Post a reply to this message

From: Christian Froeschlin
Subject: Re: Orientation and left handed frame
Date: 16 Oct 2016 16:11:11
Message: <5803dedf@news.povray.org>
On 16.10.2016 15:59, Jim Holsenback wrote:
> On 10/15/2016 6:57 PM, Christian Froeschlin wrote:
>> It may also lead to a bit more pleasing layout as the narrow
>> paragraph between two images looks a bit odd to me anyway.
>
>
http://wiki.povray.org/content/Documentation:Tutorial_Section_2#Understanding_POV-Ray.27s_Coordinate_System

*thumbs up* (haha)


Post a reply to this message

From: Jim Holsenback
Subject: Re: Orientation and left handed frame
Date: 16 Oct 2016 17:48:32
Message: <5803f5b0$1@news.povray.org>
On 10/16/2016 4:11 PM, Christian Froeschlin wrote:
> On 16.10.2016 15:59, Jim Holsenback wrote:
>> On 10/15/2016 6:57 PM, Christian Froeschlin wrote:
>>> It may also lead to a bit more pleasing layout as the narrow
>>> paragraph between two images looks a bit odd to me anyway.
>>
>>
http://wiki.povray.org/content/Documentation:Tutorial_Section_2#Understanding_POV-Ray.27s_Coordinate_System
>>
>
> *thumbs up* (haha)

took only one huh before i got it ... and yes i'll pardon the pun in 
this case


Post a reply to this message

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.