POV-Ray : Newsgroups : povray.advanced-users : Waterdrops on Glass... How? Server Time
29 Jul 2024 12:20:34 EDT (-0400)
  Waterdrops on Glass... How? (Message 31 to 34 of 34)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Timothy R  Cook
Subject: Re: Waterdrops on Glass... How?
Date: 7 Feb 2003 15:18:26
Message: <3e441492$1@news.povray.org>
Christopher James Huff wrote:
> Read the rest of this thread, what POV-Ray does has been explained. You 
> should simply overlap the surfaces slightly, this will give the correct 
> result.

No, that would be 'will give a visually acceptable result'.   Surfaces
don't overlap in the real world.

-- 
--Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


Post a reply to this message

From: Christopher James Huff
Subject: Re: Waterdrops on Glass... How?
Date: 10 Feb 2003 18:54:56
Message: <cjameshuff-E232E7.18515910022003@netplex.aussie.org>
In article <3e441492$1@news.povray.org>,
 "Timothy R. Cook" <z993126bellsouth.net> wrote:

> No, that would be 'will give a visually acceptable result'.   Surfaces
> don't overlap in the real world.

As already mentioned in this thread, the way POV handles this situation 
results in refraction being handled correctly.

Can we drop it now?

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


Post a reply to this message

From: Timothy R  Cook
Subject: Re: Waterdrops on Glass... How?
Date: 10 Feb 2003 19:22:18
Message: <3e48423a$1@news.povray.org>
Christopher James Huff wrote:
> Can we drop it now?

Water drop it, even.  hehehehhehehehehe

er

*cough*

-- 
--Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


Post a reply to this message

From: Lazlo Hollyfeld
Subject: Re: Waterdrops on Glass... How?
Date: 2 Apr 2003 19:35:31
Message: <3e8b81d3$1@news.povray.org>
Hi!  I realize this is an old posting from the POV news sever, but you can
go here to see a new technique I created to make waterdroplets do what I
want them to do on a flat, glass surface, and am working on making it happen
on a curved surface.  The piece is animated, but here are some screenshots
to look at.  All the water droplets on this image are CG created.

http://www.actlab.utexas.edu/~arie/intersection/

Arie Stavchansky


"Per Rutquist" <per### [at] volvocom> wrote in message
news:web.3e43e6949320e9d02ce39a3a0@news.povray.org...
> Water-Glass-Air problem:
>
> I've given this problem a lot of thought while trying to accurately model
a
> glass of Champagne. I've come up with four non-solutions.
>
> Model with air-gap:
>   -Doesn't work because it results in total reflection where
>    there shouldn't be. (The air gap work the same way as the
>    air gaps in optical fiber lines.)
>   -Awful render times because of rays bouncing back and forth
>    in the gap.
>
> Union with overlap:
>   -Not as much total reflection, but still incorrect.
>   -Still awful render times, because of the two surfaces.
>
> Merge with overlap:
>   -Not really correct since merged objects shouldn't have different
>    interiors.
>   -The material is determined by the ray's point of entry, and
>    doesn't change, because there is no surface at all where there
>    were two surfaces before
>
> Union + clipping.
>   -Correct number of surfaces (one) between water and glass.
>   -Problem when ray reenters air. (It doesn't, because it
>      misses the surface where it should leave the water.)
>   -Example:
>     1st surface: Enter water (Ray is in water)
>     2nd surface: Enter glass (Ray is in glass in water)
>     - Surface to leave water is clipped
>     3rd surface: Leave glass (Ray is in water, when it is actually in
air.)
>
> The only solution that I can think of would be to modify POV-ray itself.
> The feature we need is a half-merge. That is a method which takes the
> union of two objects, and keeps exactly one of the internal surfaces.
>
> /Per
>
>


Post a reply to this message

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.