POV-Ray : Newsgroups : povray.general : Grumpy Old Man! Server Time
6 Dec 2021 12:26:58 EST (-0500)
  Grumpy Old Man! (Message 1 to 7 of 7)  
From: Leroy
Subject: Grumpy Old Man!
Date: 21 Nov 2021 13:35:00
Message: <web.619a911d93f23f0364d48033f712fc00@news.povray.org>
Here's my rant:
(Trigger)
The triangular pattern is a block pattern that generates a repeating pattern of
triangles in the x-z plane.
(WHAT?)

 The 'x-z plane' and the 'y-z plane' and others in the documents has finally got
to me.

I had to say something. For years I just let pass by, I knew what it meant.
I know someone else must have said something earlier.(I couldn't find it!)

So to blow off some steam, Here I am!

The basic planes in are POV 3D world is x and y and z only.
Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
plane.
Just use in the plane object. See what you get!

I know it's just the old docs but it's annoying. And I guess the older I get the
more annoying it is.

OK, I feel better, time to go back rendering.

Have Fun!


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From: Kenneth
Subject: Re: Grumpy Old Man!
Date: 21 Nov 2021 17:35:00
Message: <web.619ac817ab07824c4cef624e6e066e29@news.povray.org>
For me, 'x-z' and similar specifications are the only sure way whereby I can
visualize what is meant. They give me an unambiguous mental picture of the plane
in question, as they are clear descriptors of the two dimensions or directions
that the plane lies in.

Here's where *I* have trouble:

When I read something like "...and place all of
your objects along the z-plane", I actually DO have a clear image of what is
meant (disregarding the *distance from the origin* that might be inferred-- I
would automatically assume a distance of zero.) The z-plane is 'horizontal and
vertical' facing the camera. No problem!

I have *sort of* a similar mental image of the 'y-plane'-- although it starts
getting muddy in my mind as to why it isn't exactly like the 'z-plane'(!). I
always have to think hard about it before it becomes clear :-(  Like, "Is it
horizontal or vertical? And which 'direction' is its surface facing?" I have an
even worse problem with a simple 'x-plane' specification!

Maybe my own difficulty has to do with the fact that the CAMERA usually faces
+z-- so seeing a simple 'z-plane' description seems obvious to me, whereas the
others do not.


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From: Kenneth
Subject: Re: Grumpy Old Man!
Date: 21 Nov 2021 18:05:00
Message: <web.619acf77ab07824c4cef624e6e066e29@news.povray.org>
"Leroy" <whe### [at] gmailcom> wrote:
>
> The basic planes in are POV 3D world is x and y and z only.
> Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
> plane.
>

Ha! I didn't initially grasp your main rant that 'x-z plane' could be read as
     'x minus z'

Yeah, that could be confusing, to say the least!


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From: Mr
Subject: Re: Grumpy Old Man!
Date: 22 Nov 2021 05:20:00
Message: <web.619b6dbeab07824c16086ed03f378f2@news.povray.org>
"Leroy" <whe### [at] gmailcom> wrote:
> Here's my rant:
> (Trigger)
> The triangular pattern is a block pattern that generates a repeating pattern of
> triangles in the x-z plane.
> (WHAT?)
>
>  The 'x-z plane' and the 'y-z plane' and others in the documents has finally got
> to me.
>
> I had to say something. For years I just let pass by, I knew what it meant.
> I know someone else must have said something earlier.(I couldn't find it!)
>
> So to blow off some steam, Here I am!
>
> The basic planes in are POV 3D world is x and y and z only.
> Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
> plane.
> Just use in the plane object. See what you get!
>
> I know it's just the old docs but it's annoying. And I guess the older I get the
> more annoying it is.
>
> OK, I feel better, time to go back rendering.
>
> Have Fun!

Hello, sorry if I missed something in other discussions, but theoretically there
is no such thing as an old documentation, is there? Maybe you should point all
places that make you feel that way? In the discussion page of the source for the
very topic you mention, a pointer to here was just added so discussion can go on
either here or there, but some propositions need to be made /validated:

https://wiki.povray.org/content?title=Reference_Talk:Triangular_Pattern&action=edit&redlink=1

Thanks a lot for suggesting such improvements.


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From: Ash Holsenback
Subject: Re: Grumpy Old Man!
Date: 22 Nov 2021 06:43:08
Message: <619b824c$1@news.povray.org>
On 11/21/21 6:00 PM, Kenneth wrote:
> "Leroy" <whe### [at] gmailcom> wrote:
>>
>> The basic planes in are POV 3D world is x and y and z only.
>> Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
>> plane.
>>
> 
> Ha! I didn't initially grasp your main rant that 'x-z plane' could be read as
>       'x minus z'
> 
> Yeah, that could be confusing, to say the least!
> 
> 
> 

lord help /all/ of ya


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From: Bald Eagle
Subject: Re: Grumpy Old Man!
Date: 22 Nov 2021 07:05:00
Message: <web.619b8694ab07824c1f9dae3025979125@news.povray.org>
"Leroy" <whe### [at] gmailcom> wrote:

> The basic planes in are POV 3D world is x and y and z only.
> Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
> plane.
> Just use in the plane object. See what you get!

Well, it's just a function of the long history of development - and the metric
ton of documentation that had to be written, and so written quickly.

It is probably not meant to be a "minus" but a "dash" or "hyphen", but that
would require messy unicode stuff...

https://www.punctuationmatters.com/the-difference-between-a-dash-and-a-minus-sign/

Perhaps one could refer to it as
the x&z plane (awkward)
the xz plane (NOT the x*z surface)
the x & z axis plane

But the best way might be "the y--normal plane", which would give a simpler
description, consistent with the SDL syntax and mathematical description of the
plane, and provide the putative missing directional information.

In defense of the extant notation, the simplest interpretation wouldn't be an
equation for a wonky plane, but a plane extending in the directions of those two
cardinal axes.

"Make sure your dried frog pills are in your daily pill organizer, you crusty
old codger."  :P


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From: Alain Martel
Subject: Re: Grumpy Old Man!
Date: 23 Nov 2021 11:46:46
Message: <619d1af6$1@news.povray.org>
Le 2021-11-21 à 13:34, Leroy a écrit :
> Here's my rant:
> (Trigger)
> The triangular pattern is a block pattern that generates a repeating pattern of
> triangles in the x-z plane.
> (WHAT?)
> 
>   The 'x-z plane' and the 'y-z plane' and others in the documents has finally got
> to me.
> 
> I had to say something. For years I just let pass by, I knew what it meant.
> I know someone else must have said something earlier.(I couldn't find it!)
> 
> So to blow off some steam, Here I am!
> 
> The basic planes in are POV 3D world is x and y and z only.
> Strictly speaking the x-z plane is a set of points that x-z=0 make a funky
> plane.
> Just use in the plane object. See what you get!
> 
> I know it's just the old docs but it's annoying. And I guess the older I get the
> more annoying it is.
> 
> OK, I feel better, time to go back rendering.
> 
> Have Fun!
> 
> 

When the X-Z plane is mentioned, that mean the plane that contain the X 
and Z axis. The normal of that plane is parallel to the Y axis.

It is a common notation to refer to a plane using two intersecting 
lines. It's a convention that I learned in high school.
Also, from my high school days, I learned that +X is to the right, +Y is 
the up and +Z is forward and that positive rotation is counter clockwise.

So, for me, it's totally obvious.


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