Hey All,

I tried rendering my kitchen visualization with some really neat-o radiosity
settings, but all my bump maps got completely washed out. Is there a way in
POV-Ray or MegaPov to use my map to modify the actual geometry and not just
the normals? Height-fields would do it, I suppose, but I like the repeating
pattern of bump-maps. I was reading something about isosurfaces and
bump-maps in earlier threads, but I don't know how isosurfaces work; anyone
know a good explanation or tutorial?

Thanks,
D.J.

Post a reply to this message

"D.J. Brown" wrote:
> 
> Hey All,
> 
> I tried rendering my kitchen visualization with some really neat-o radiosity
> settings, but all my bump maps got completely washed out. Is there a way in
> POV-Ray or MegaPov to use my map to modify the actual geometry and not just
> the normals? Height-fields would do it, I suppose, but I like the repeating
> pattern of bump-maps. I was reading something about isosurfaces and
> bump-maps in earlier threads, but I don't know how isosurfaces work; anyone
> know a good explanation or tutorial?
> 
> Thanks,
> D.J.

Have you tried "normal on" in the radiosity block ?

If that does not help, you can add bumpiness to all isosurfaces, see the megapov
sample files for details.  It should not be a problem to define a wall, etc. as
isosurface, it's only much slower :-)

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

Post a reply to this message

In article <399aa57a@news.povray.org>, "D.J. Brown" 
<ext### [at] hotmailcom> wrote:

> I tried rendering my kitchen visualization with some really neat-o 
> radiosity settings, but all my bump maps got completely washed out.

This is because by default radiosity ignores perturbations to the object 
normal. In MegaPOV, you can tell it to take normal patterns into 
account(including bump_maps): just add "normal on" to the radiosity {} 
block in global_settings.


> Is there a way in POV-Ray or MegaPov to use my map to modify the 
> actual geometry and not just the normals?

Not directly, you would have to make a function representing your object 
an use an isosurface.


> Height-fields would do it, I suppose, but I like the repeating 
> pattern of bump-maps. I was reading something about isosurfaces and 
> bump-maps in earlier threads, but I don't know how isosurfaces work; 
> anyone know a good explanation or tutorial?

There are a couple isosurface tutorials:
http://www.hamiltonite.pwp.blueyonder.co.uk/
        raytracing/STBenge/stbenge.html

http://www.econym.demon.co.uk/isotut/

-- 
Christopher James Huff
Personal: e-mail chr### [at] maccom, Web page http://homepage.mac.com/chrishuff/
TAG: e-mail chr### [at] tagpovrayorg, Web page http://tag.povray.org/

><>

Post a reply to this message

Wouldn't you know... I decided that I should convert them all to
height-fields and I spent the past hour redoing my architecture when all I
needed to do was put "normal on" in the radiosity block. Then again... I
guess I haven't lost any time since I would've checked the newsgroup at the
same time and been just as far along. Thanks for the plethora of info.

Let me see if I have this correct on iso-surfaces... Basically, it evaluates
a function at points x, y, z inside my bounding region and creates a surface
point with that if my function evaluates at or above a certain threshold? Or
does it create a mesh like the height-field does? Or does it simply refer to
the provided function every time it calculates a point... creating a
pseudo-infinitely detailed surface?

Thanks in advance for any help,
D.J.

"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-4EAD1F.10534516082000@news.povray.org...
> In article <399aa57a@news.povray.org>, "D.J. Brown"
> <ext### [at] hotmailcom> wrote:
>
> > I tried rendering my kitchen visualization with some really neat-o
> > radiosity settings, but all my bump maps got completely washed out.
>
> This is because by default radiosity ignores perturbations to the object
> normal. In MegaPOV, you can tell it to take normal patterns into
> account(including bump_maps): just add "normal on" to the radiosity {}
> block in global_settings.
>
>
> > Is there a way in POV-Ray or MegaPov to use my map to modify the
> > actual geometry and not just the normals?
>
> Not directly, you would have to make a function representing your object
> an use an isosurface.
>
>
> > Height-fields would do it, I suppose, but I like the repeating
> > pattern of bump-maps. I was reading something about isosurfaces and
> > bump-maps in earlier threads, but I don't know how isosurfaces work;
> > anyone know a good explanation or tutorial?
>
> There are a couple isosurface tutorials:
> http://www.hamiltonite.pwp.blueyonder.co.uk/
>         raytracing/STBenge/stbenge.html
>
> http://www.econym.demon.co.uk/isotut/
>
> --
> Christopher James Huff
> Personal: e-mail chr### [at] maccom, Web page
http://homepage.mac.com/chrishuff/
> TAG: e-mail chr### [at] tagpovrayorg, Web page http://tag.povray.org/
>
> ><>

Post a reply to this message

In article <399ac844@news.povray.org>, "D.J. Brown" 
<ext### [at] hotmailcom> wrote:

> Wouldn't you know... I decided that I should convert them all to 
> height-fields and I spent the past hour redoing my architecture when 
> all I needed to do was put "normal on" in the radiosity block. Then 
> again... I guess I haven't lost any time since I would've checked the 
> newsgroup at the same time and been just as far along. Thanks for the 
> plethora of info.

Ouch...I hope you saved the original scene file first.


> Let me see if I have this correct on iso-surfaces... Basically, it 
> evaluates a function at points x, y, z inside my bounding region and 
> creates a surface point with that if my function evaluates at or 
> above a certain threshold? Or does it create a mesh like the 
> height-field does? Or does it simply refer to the provided function 
> every time it calculates a point... creating a pseudo-infinitely 
> detailed surface?

It uses the provided function every time it needs to calculate a point. 
By default, points with a value higher than the threshold are inside the 
surface, lower values are outside, and the algorithm "searches" along 
the ray for the intersection points. It is not tesselated to triangles, 
it is a surface just like a sphere or cone primitive, though the solving 
method is very different from any other primitive in the official 
version.

-- 
Christopher James Huff
Personal: e-mail chr### [at] maccom, Web page http://homepage.mac.com/chrishuff/
TAG: e-mail chr### [at] tagpovrayorg, Web page http://tag.povray.org/

><>

Post a reply to this message

Backupsss? Backupsss? We don't need no stinkin' backupsss! Actually, based
on the isosurphace information you led me to I wrote a macro for applying
displacement mapping to the surface of my walls. It's looking really nice
(even a decently realistic render with the render quality set at 4). I just
have to figure out how to round off the edges now... Very sharp and deadly
walls in this place.

Thanks!

"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-915E10.13141216082000@news.povray.org...
> In article <399ac844@news.povray.org>, "D.J. Brown"
> <ext### [at] hotmailcom> wrote:
>
> > Wouldn't you know... I decided that I should convert them all to
> > height-fields and I spent the past hour redoing my architecture when
> > all I needed to do was put "normal on" in the radiosity block. Then
> > again... I guess I haven't lost any time since I would've checked the
> > newsgroup at the same time and been just as far along. Thanks for the
> > plethora of info.
>
> Ouch...I hope you saved the original scene file first.
>
>
> > Let me see if I have this correct on iso-surfaces... Basically, it
> > evaluates a function at points x, y, z inside my bounding region and
> > creates a surface point with that if my function evaluates at or
> > above a certain threshold? Or does it create a mesh like the
> > height-field does? Or does it simply refer to the provided function
> > every time it calculates a point... creating a pseudo-infinitely
> > detailed surface?
>
> It uses the provided function every time it needs to calculate a point.
> By default, points with a value higher than the threshold are inside the
> surface, lower values are outside, and the algorithm "searches" along
> the ray for the intersection points. It is not tesselated to triangles,
> it is a surface just like a sphere or cone primitive, though the solving
> method is very different from any other primitive in the official
> version.
>
> --
> Christopher James Huff
> Personal: e-mail chr### [at] maccom, Web page
http://homepage.mac.com/chrishuff/
> TAG: e-mail chr### [at] tagpovrayorg, Web page http://tag.povray.org/
>
> ><>

Post a reply to this message

"D.J. Brown" wrote:
> I just
> have to figure out how to round off the edges now... Very sharp and deadly
> walls in this place.
> 
> Thanks!
> 


We like our walls the same as we like our blue screens... deadly.

Post a reply to this message