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  first-time user.. help angling mirrors? (Message 1 to 3 of 3)  
From: Marina
Subject: first-time user.. help angling mirrors?
Date: 26 Jun 2011 15:05:01
Message: <web.4e0782476572a79ce088a3220@news.povray.org>
Okay, I'm supposed to construct this 4-mirror apparatus on POV-Ray. Here is the
drawing from which I'm supposed to do this from:

http://i1003.photobucket.com/albums/af151/mbradar2/povrayforumfigure.png

I have it on the -z axis. It is 4 mirrors.. the squares that are darker are the
backs of the mirrors, and the squares that are lighter are the fronts - the
actual reflective surfaces of the mirrors. Light goes in from the left and
bounces through the mirrors and comes out to the right. This is for physics..
polarized electrons and all.

Anyway, on POV-Ray, I have four 'boxes' on the -z axis, but I can't figure out
how to angle them so they look like the picture.. they are more rhombuses in the
picture, but I can make them look like rhombuses just by changing the camera,
can I not?

I have one square near the area of <0,0,-13>, lying flat there on the z-plane.
But I don't want it flat, I want it upright.. however, when I change the
z-variable of the rotation ( like <0,0,45> for 45 degrees), it doesn't just
angle it, it moves it away from its original spot.

How do I angle it without it moving away? That's my main question.

Or is there a better technique to constructing those 4 mirrors? I'm having a
very difficult time with this since I just started using this program yesterday
and my boss was hoping to have this done in a couple of days. He knows I don't
know the program and it's not super important that he have this done because he
has a bare-skeleton version already, but he'd like a cool 3D version since he's
submitting a scientific paper, and he doesn't know anyone who uses this program
so I'm his last resort. So if anyone can help me out with a sort-of-quick (1 to
2-day max) way to construct those mirrors, I would be eternally grateful.


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From: Jim Holsenback
Subject: Re: first-time user.. help angling mirrors?
Date: 26 Jun 2011 15:50:20
Message: <4e078d7c$1@news.povray.org>
On 06/26/2011 04:02 PM, Marina wrote:
> Okay, I'm supposed to construct this 4-mirror apparatus on POV-Ray. Here is the
> drawing from which I'm supposed to do this from:
>
> http://i1003.photobucket.com/albums/af151/mbradar2/povrayforumfigure.png
>
> I have it on the -z axis. It is 4 mirrors.. the squares that are darker are the
> backs of the mirrors, and the squares that are lighter are the fronts - the
> actual reflective surfaces of the mirrors. Light goes in from the left and
> bounces through the mirrors and comes out to the right. This is for physics..
> polarized electrons and all.
>
> Anyway, on POV-Ray, I have four 'boxes' on the -z axis, but I can't figure out
> how to angle them so they look like the picture.. they are more rhombuses in the
> picture, but I can make them look like rhombuses just by changing the camera,
> can I not?
>
> I have one square near the area of<0,0,-13>, lying flat there on the z-plane.
> But I don't want it flat, I want it upright.. however, when I change the
> z-variable of the rotation ( like<0,0,45>  for 45 degrees), it doesn't just
> angle it, it moves it away from its original spot.
>
> How do I angle it without it moving away? That's my main question.
>
> Or is there a better technique to constructing those 4 mirrors? I'm having a
> very difficult time with this since I just started using this program yesterday
> and my boss was hoping to have this done in a couple of days. He knows I don't
> know the program and it's not super important that he have this done because he
> has a bare-skeleton version already, but he'd like a cool 3D version since he's
> submitting a scientific paper, and he doesn't know anyone who uses this program
> so I'm his last resort. So if anyone can help me out with a sort-of-quick (1 to
> 2-day max) way to construct those mirrors, I would be eternally grateful.
>
>
try building everything at the origin ... angle them properly, /then/ 
translate them to their final resting position


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From: Alain
Subject: Re: first-time user.. help angling mirrors?
Date: 26 Jun 2011 16:36:36
Message: <4e079854@news.povray.org>

> Okay, I'm supposed to construct this 4-mirror apparatus on POV-Ray. Here is the
> drawing from which I'm supposed to do this from:
>
> http://i1003.photobucket.com/albums/af151/mbradar2/povrayforumfigure.png
>
> I have it on the -z axis. It is 4 mirrors.. the squares that are darker are the
> backs of the mirrors, and the squares that are lighter are the fronts - the
> actual reflective surfaces of the mirrors. Light goes in from the left and
> bounces through the mirrors and comes out to the right. This is for physics..
> polarized electrons and all.
>
> Anyway, on POV-Ray, I have four 'boxes' on the -z axis, but I can't figure out
> how to angle them so they look like the picture.. they are more rhombuses in the
> picture, but I can make them look like rhombuses just by changing the camera,
> can I not?
>
> I have one square near the area of<0,0,-13>, lying flat there on the z-plane.
> But I don't want it flat, I want it upright.. however, when I change the
> z-variable of the rotation ( like<0,0,45>  for 45 degrees), it doesn't just
> angle it, it moves it away from its original spot.
>
> How do I angle it without it moving away? That's my main question.
>
> Or is there a better technique to constructing those 4 mirrors? I'm having a
> very difficult time with this since I just started using this program yesterday
> and my boss was hoping to have this done in a couple of days. He knows I don't
> know the program and it's not super important that he have this done because he
> has a bare-skeleton version already, but he'd like a cool 3D version since he's
> submitting a scientific paper, and he doesn't know anyone who uses this program
> so I'm his last resort. So if anyone can help me out with a sort-of-quick (1 to
> 2-day max) way to construct those mirrors, I would be eternally grateful.
>
>

Whenever you rotate, or scale, anything, it's done relative to the 
origin, or coordinate <0,0,0>.

So, create on object called Mirror with it's working face centered there.

You can then rotate it in place, THEN translate it to the desired position.
#declare Mirror=box{...photons{target reflection on collect off}}
object{Mirror rotate<0,0,45> translate<0,0,-13>}
oblect{Mirror rotate<0,0,225> translate<0,13,-13>}

In the image the mirrows only look like rombus due to faked perspective.

Now, a tip for a rendering showing the light as it passes through that 
aparatus:
If you want the light to be reflected, you need to enable photons 
maping. It's done by adding a photons block in the global_settings 
section. You also must add a photons block to your mirrors to enable the 
shooting of photons at them and for the photons to get reflected. It 
will add some time between parsing and the rendering itself.
Please read the photons section of the documentations.

If you want the path of the light to be visible, you need to use the 
media feature. Here, you'll need scattering media. This will increase 
the rendering time.
Please read the media section of the documentations.

POV-Ray don't know anything about polarisation of the light. You can't 
simulate it.



Alain


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