I came across a Lightwave 7 review and it featured a picture to show
Lightwave's caustic capabilities.  The picture is fairly simple so I decided
to try and duplicate it in POV-Ray 3.5 rc6.  The first picture is from
Lightwave (in case it posts in reverse order, the one with the brighter
glass spheres) and the second picture is what I rendered.  The most notable
differences are caustics that appear on the blue wall (I don't know how they
achieved the caustics to appear white) and the subtle highlights and shadows
on the red wall in Lightwave's render (I'm not sure how to get that effect
either).  Oh yeah, and the light on the ceiling in my render does not appear
to be "in the ceiling" (although it is...it shows if I don't render with
radiosity) and the shadows aren't as soft.

-Paragon

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Attachments:
Download 'draft.jpg' (17 KB) Download 'caustics_f_02_lightwave.jpg' (21 KB)

Preview of image 'draft.jpg'

Preview of image 'caustics_f_02_lightwave.jpg'

In article <3d28a6a1@news.povray.org>, "Paragon" <use### [at] hostcom> wrote:

> I came across a Lightwave 7 review and it featured a picture to show
> Lightwave's caustic capabilities.  The picture is fairly simple so I decided
> to try and duplicate it in POV-Ray 3.5 rc6.  The first picture is from
> Lightwave (in case it posts in reverse order, the one with the brighter
> glass spheres) and the second picture is what I rendered.  The most notable
> differences are caustics that appear on the blue wall (I don't know how they
> achieved the caustics to appear white) and the subtle highlights and shadows
> on the red wall in Lightwave's render (I'm not sure how to get that effect
> either).  Oh yeah, and the light on the ceiling in my render does not appear
> to be "in the ceiling" (although it is...it shows if I don't render with
> radiosity) and the shadows aren't as soft.

The metal balls in your image have a fairly blurry texture, the 
Lightwave ones have barely any blur at all. The camera is slightly 
off...look how the room corners meet the image corners in the Lightwave 
room. Also, the POV room looks like it is about twice the size of the 
Lightwave room, judging from the reflections...it looks like there is a 
wall just behind the camera in the Lightwave room, and one twice as far 
away in the POV one. And I think the POV glass objects look washed out 
in comparison because the texture isn't entirely transparent...I like to 
use a 100% transparent pigment and some attenuation or media in glass 
materials.

As for the shadows...your area light might be half as big as it should 
be. And it looks like you might have left the default ambient values in.

Source code?

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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"Paragon" <use### [at] hostcom> wrote in message news:3d28a6a1@news.povray.org...
> I came across a Lightwave 7 review and it featured a picture to show
> Lightwave's caustic capabilities.  The picture is fairly simple so I
decided
> to try and duplicate it in POV-Ray 3.5 rc6.  The first picture is from
> Lightwave (in case it posts in reverse order, the one with the brighter
> glass spheres) and the second picture is what I rendered.  The most
notable
> differences are caustics that appear on the blue wall (I don't know how
they
> achieved the caustics to appear white) and the subtle highlights and
shadows
> on the red wall in Lightwave's render (I'm not sure how to get that effect
> either).  Oh yeah, and the light on the ceiling in my render does not
appear
> to be "in the ceiling" (although it is...it shows if I don't render with
> radiosity) and the shadows aren't as soft.

Don't know about Lightwave, but it could be that the light has a
"brightness" value over the "maximum". That way it makes the spot on the
wall white. Just a thought.

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> Lightwave ones have barely any blur at all. The camera is slightly
> off...look how the room corners meet the image corners in the Lightwave
> room. Also, the POV room looks like it is about twice the size of the
> Lightwave room, judging from the reflections...it looks like there is a
> wall just behind the camera in the Lightwave room, and one twice as far
> away in the POV one. And I think the POV glass objects look washed out
> in comparison because the texture isn't entirely transparent...I like to
> use a 100% transparent pigment and some attenuation or media in glass
> materials.

Yeah, I blurred the reflection a little too much,  I'll have to fix that.
And the POV room is longer than the Lightwave room.  Actually, I don't know
how to adjust the camera properly so that I can get a good perspective in
such a small room.

> Source code?
I'll post in povray.text.scene-files.  If you can adjust and get better
results,
please post results (and adjusted settings).

-Paragon

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> from Lightwave (in case it posts in reverse order ..

It does come up reversed, but why?

Anyway I thought your picture was the lower one and I preferred the upper
one.. Now I see the upper one is yours, congratulations!  ;o)

Regards,
Hugo

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What you can do for the back wall is use a plane with an interior texture
using the wall texture and for the exterior texture make it transparent so
you can see through it like a window and place the camera farther back.

"Paragon" <use### [at] hostcom> wrote in message news:3d28cd36@news.povray.org...
>
>Actually, I don't know
> how to adjust the camera properly so that I can get a good perspective in
> such a small room.

Post a reply to this message

"Paragon" <use### [at] hostcom> wrote...
> I came across a Lightwave 7 review and it featured a picture to show
> Lightwave's caustic capabilities.  The picture is fairly simple so I
decided
> to try and duplicate it in POV-Ray 3.5 rc6.  The first picture is from
> Lightwave (in case it posts in reverse order, the one with the brighter
> glass spheres) and the second picture is what I rendered.  The most
notable
> differences are caustics that appear on the blue wall (I don't know how
they
> achieved the caustics to appear white)

Instead of using rgb<0,0,1> for your wall, use something not quite so
perfect, like rgb<0.01, 0.01, 1.0>.  The non-zero components for red and
green will allow the wall to show colors other than blue.

> and the subtle highlights and shadows
> on the red wall in Lightwave's render (I'm not sure how to get that effect
> either).

Did you enable reflection photons for the glass spheres and metal spheres?
Also, their spheres might have a bit more reflection.  You might also want
to consider the possibility that those "subtle highlights" might be
aretefacts (though the more likely scenario is internal reflection in the
glass spheres).

Your image is very nice, though!

-Nathan

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> It does come up reversed, but why?
I use Outlook Express for browsing the newsgroups and when I attach files,
it orders them alphabetically them posts them in the reverse order.  I
always get this confused though.

> Anyway I thought your picture was the lower one and I preferred the upper
> one.. Now I see the upper one is yours, congratulations!  ;o)
Thanks!

-Paragon

Post a reply to this message

> Did you enable reflection photons for the glass spheres and metal spheres?
> Also, their spheres might have a bit more reflection.  You might also want
> to consider the possibility that those "subtle highlights" might be
> aretefacts (though the more likely scenario is internal reflection in the
> glass spheres).

> Your image is very nice, though!

Thanks for the comments and suggestions, learning POV-Ray is an ever growing
process for me.

-Paragon

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> I came across a Lightwave 7 review and it featured a picture to show
> Lightwave's caustic capabilities.  The picture is fairly simple so I
decided
> to try and duplicate it in POV-Ray 3.5 rc6.  The first picture is from
> Lightwave (in case it posts in reverse order, the one with the brighter
> glass spheres) and the second picture is what I rendered.  The most
notable
> differences are caustics that appear on the blue wall (I don't know how
they
> achieved the caustics to appear white) and the subtle highlights and
shadows
> on the red wall in Lightwave's render (I'm not sure how to get that effect
> either).  Oh yeah, and the light on the ceiling in my render does not
appear
> to be "in the ceiling" (although it is...it shows if I don't render with
> radiosity) and the shadows aren't as soft.

Personally I disagree that the "most notable differences are caustics"... I
think the most notable difference is the price of the software!!!!

LW = $1,595
POVRay = $0

I know which is best value for money!

Rarius

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