I have been working on an image for the Sept-Oct IRTC stills competition (yes, I
know it's over... I didn't get started soon enough :( and have run into some
problems using media, and perhaps radiosity.  I don't know if radiosity is
involved because I've been rendering with rad on and haven't tweaked the non-rad
lighting yet to be able to tell for sure.

Anyway, the problem.  I've included two pictures here.  The first looks the way
I want it to, but there's no ground plane (and the rest of the image isn't even
close do done :)  The second adds a ground plane, but there are artifacts on the
hands of the left image.  I figure it's because of the ground plane, but I have
no idea how to fix it.  Any suggestions?

Also, I can't seem to get rid of the seam in the staff on the right.  I'm using
mrege and the cone and cylinder are slightly overlapped.

Thanks!

Michael
--
#macro M(D)#local J=strlen(D);#local _=""#while(J>0)#local _=concat(_,substr(D
,J,1))#local J=J-1;#end _#end sphere{z*9,5pigment{rgb x}}#macro N(D,J)text{ttf
"timrom.ttf"M(D)1,0 translate-J}#end#macro O(E,K)#local _=N(E,K)light_source{-
z*9rgb 1projected_through{_}}#end O("leahciM"<1.6,-.3.9>)O("nosnhoJ"<1.6.9.9>)

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Attachments:
Download 'WarfareVI.jpg' (33 KB) Download 'WarfareVII.jpg' (43 KB)

Preview of image 'WarfareVI.jpg'

Preview of image 'WarfareVII.jpg'

BTW, those hands are from Rune's hands include file, with some small changes.

Michael

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1) What are your media settings?

2) The "intervals" keyword may be interpreted differently with and
without the plane.  POV figures out how to sample the media by splitting
the ray into a certain number of intervals inside the media.  IF the
media isn't contained by an object, then the intervals are calculated
based on the distance to the first intersection.  So, the plane might
make a difference there.

3) otherwise, I'm stumped.

- Ben

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"Redbeard \(MDJohnson\)" <red### [at] wvadelphianet> wrote in
news:3be48328@news.povray.org: 

> I figure it's because of the ground plane, but I have no idea how to fix
> it.  Any suggestions? 

Assuming you don't have coincident surfaces in the media container, I'd say 
you've run into a bug.  You might be able to hide the artifacts by ramping 
up your AA settings, but other than that you appear to be out of luck.

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"Coridon Henshaw" <che### [at] sympaticoca> wrote in message
news:Xns### [at] 204213191226...
> "Redbeard \(MDJohnson\)" <red### [at] wvadelphianet> wrote in
> news:3be48328@news.povray.org:
>
> > I figure it's because of the ground plane, but I have no idea how to fix
> > it.  Any suggestions?
>
> Assuming you don't have coincident surfaces in the media container, I'd say
> you've run into a bug.  You might be able to hide the artifacts by ramping
> up your AA settings, but other than that you appear to be out of luck.

There shouldn't be any coincident surfaces, since it is several groups of blobs
merged together.  I'm going to do some more playing with the media settings
today and see what I come up with.

Thanks,
Michael

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"Ben Birdsey" <cla### [at] mailcom> wrote in message
news:3BE4D430.CFF9D217@mail.com...
>
> 1) What are your media settings?
Right now, defaults.  I'm going to start playing today...
>
> 2) The "intervals" keyword may be interpreted differently with and
> without the plane.  POV figures out how to sample the media by splitting
> the ray into a certain number of intervals inside the media.  IF the
> media isn't contained by an object, then the intervals are calculated
> based on the distance to the first intersection.  So, the plane might
> make a difference there.
I'll check into that first.  The media IS in an object, though.

> 3) otherwise, I'm stumped.
I'll play with it some more... I just didn't have any idea of what to try until
you mentioned intervals.  Thanks.
> - Ben

Thanks for the help,
Michael

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Wasn't it Redbeard (MDJohnson) who wrote:

>Also, I can't seem to get rid of the seam in the staff on the right.  I'm using
>mrege and the cone and cylinder are slightly overlapped.

Such a seam is perfectly correct for the change in lighting angle at the
junction of a cone and cylinder. (Take a look at an unpainted pencil).
I'd suggest using a lathe object or a surface of revolution instead.

-- 
Mike Williams
Gentleman of Leisure

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"Mike Williams" <mik### [at] nospamplease> wrote in message
news:Z7s### [at] econymdemoncouk...
> Wasn't it Redbeard (MDJohnson) who wrote:
>
> >Also, I can't seem to get rid of the seam in the staff on the right.  I'm
using
> >mrege and the cone and cylinder are slightly overlapped.
>
> Such a seam is perfectly correct for the change in lighting angle at the
> junction of a cone and cylinder. (Take a look at an unpainted pencil).
> I'd suggest using a lathe object or a surface of revolution instead.
>

Actually, these pieces are just temporary.  However, the problem I'm referring
to isn't the outside seam (I do expect to see the transition) but is the seam
that is visible through the semi-transparent object at the junction.  In other
words, you can see the entire face of the cylinder/cone.  It appears, though,
that this problem has rectified itself.  Perhaps I *didn't* have everything set
as I thought I did and later fixed it.  I'm not sure.

I've still got problems with the media, though.  The lower blue hand is outlined
with white artifacts.  This is the only one through which the plane is visible.
I've tried a number of media settings, and nothing seems to fix it.  I'm in the
process of eliminating problems and will post again once I have something better
to show.

Michael

--
#declare R=<8,4,.6>/3;#declare C=function{pattern{object{text{ttf"crystal.ttf"
"MDJ"1,0translate-R/4}}}}camera{location-z*30}box{-R,R pigment{rgbf 1}interior
{media{emission.1density{function{C(x,y,z)}density_map{[0mandel 50color_map{[0
rgb 0][.2rgb x][1rgb x+y]}interior 1,1.5scale 60translate<-33.75,2.85>exponent
4][1rgb<2,2>]}}}}scale 24hollow}// (c) 2001 MDJohnson red### [at] wvadelphianet

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"Redbeard" <red### [at] wvadelphianet> wrote in message
news:3be5d7e0$1@news.povray.org...
> I've still got problems with the media, though.  The lower blue hand is
outlined
> with white artifacts.  This is the only one through which the plane is
visible.
> I've tried a number of media settings, and nothing seems to fix it.  I'm in
the
> process of eliminating problems and will post again once I have something
better
> to show.
>
> Michael

I think I found the problem.  It appears to be a bug.  See my post in p.b-t on
blobs and media (http://news.povray.org/3be5f0b2@news.povray.org)

Michael

--
camera{location<8,20>look_at<6,0,4>}light_source{<8,8>rgb 1}difference{union{
#macro M(D,J)#local R=asc(substr(D,J,1))-32;<div(R,10)*2,mod(R,10)>#end#macro
E(D,B,R)prism{-D,4+D,R#local C=1;#while(C<R+1)M(B,C)#local C=C+1;#end}#end E(
0," (2:FPKAD80* U_dZU"18)sphere{2,2}#macro T(N)cylinder{<9,-N,3><9,4+N,3>3-N}
#end T(0)}T(2)E(1"45LNXUK4"8)pigment{rgb x+y/2}}//(c)2001 MDJohnson(Redbeard)

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