Hello all,
I'm modeling an interior scene in Rhino 1.1  that contains a small wood
stove type fireplace.  The stove has a screen over it's opening.  I'm
debating on whether to create the screen with simple geometry for realism,
or to find a shader with opacity and displacement mapping.

My question to this group would be: Is there a shader available within
Moray/povray that would allow me to see through the screen to the interior
of the fireplace?

I've put this question to the Rhino newsgroup and have had some good
suggestions which I've pasted below:



HI Steve- I guess it depends upon the density of the screen- if it looks
like adding too much tiny geometry then you are probably better off with
scrren texture, but if it's a biggish screen and the views you are planning
are close, then geometry might make more sense.

-Pascal


Hi Steve,


> I'm modeling a wood burning stove that has a screen over its opening.  I'm
> curious whether I should create a patch surface over the screen and then
> apply a screen shader, or if I should create a screen type geometry and
> apply a simple metal shader to the screen.  Any thoughts?

I just completed a screen for a center channel speaker. I wouldn't model
it in complete 3d or even as a plane with holes. I crashed Rhino trying
it, just too many surfaces for rhino. But I did create the grill work in
Rhino using 2d curves, even these became hard to manipulate because you
will have to make a lot of them to resemble a real screen. I then saved
the file as .ai and brought it into Photoshop and created a targa image
that I used as an alpha channel in max.

Sincerely,
Roland Montijo,
Rol### [at] aolcom

It looks like I've stumbled over a problem area.  My goal would be to be
able to see through the screen to the objects inside the stove like the
grate and maybe a log or two, just as in real life.  It seems that a shader
over a surface would be opaque.  Could make a fret work of  small pipes from
arrayed lines. Using fewer than normal pipes.   I'm not sure I understand
the use of the alpha channel and how it might be employed  in Moray which
I'm using.  Perhaps this is something I should study up on.

Thanks for your thoughts.

later,
Steve Clarke
Gresham, Oregon

Hi Steve


>>I'm not sure I understand the use of the alpha channel and how it might be
employed  in Moray which
I'm using.  Perhaps this is something I should study up on.<<

Sorry I don't know Moray but perhaps it supports transparency mapping
someone on this list might know. Basically transparency mapping/alpha
channeling drops out all the black pixels or whatever pixels you choose
in a bitmap so that when your rendering program renders the image the
final rendering lets you see through the applied bitmap where the black
pixels would be. This ends up saving large amounts of geometry and thus
rendering faster because you are using a bitmap to supply the
information.

This is also a technique you see used for outdoor or plant scenes where
the computer just can't cope with all the millions of leaves.

Sincerely,
Roland Montijo
Rol### [at] aolcom

On Wed, 23 Feb 2000 21:47:21 -0800, "Steve Clarke"
<scl### [at] teleportcom> wrote:

>It looks like I've stumbled over a problem area.  My goal would be to be
>able to see through the screen to the objects inside the stove like the
>grate and maybe a log or two, just as in real life.  It seems that a shader
>over a surface would be opaque.  Could make a fret work of  small pipes
from
>arrayed lines. Using fewer than normal pipes.

To get an idea what Rhino takes cool as a number of pipes see
attached.

steff
(attachment not included for sake of bandwidth sc)

Steve Clarke <scl### [at] teleportcom> wrote:
>...
> over a surface would be opaque.  Could make a fret work of  small pipes
from
> arrayed lines. Using fewer than normal pipes.
>...

I think you could also just make an array of narrow Plane or 3DFace
objects. They will be black anyway, right?
The simpler the screen geometry, the faster it will mesh and render.

-Mikko

Mikko Oksanen
Robert McNeel & Associates



Steve,

If your using a renderer that does opacity and displacement mapping.
You can create a 2d texture of the screen you want and use it as a bump
map and an opactiy map.  I've done this a lot and it lets you see
through the holes, and really looks cool.  Plus there's no extra
geometry to build.

The new version of Bmrt comes with a shader that has that capability.

Maybe an option...

Brian Perry

Post a reply to this message

You can create a texture with trasnparency to do that.  Should take about
5-10 minutes...

Mike

"Steve Clarke" <scl### [at] teleportcom> wrote in message
news:38b585c0@news.povray.org...
> Hello all,
> I'm modeling an interior scene in Rhino 1.1  that contains a small wood
> stove type fireplace.  The stove has a screen over it's opening.  I'm
> debating on whether to create the screen with simple geometry for realism,
> or to find a shader with opacity and displacement mapping.
>
> My question to this group would be: Is there a shader available within
> Moray/povray that would allow me to see through the screen to the interior
> of the fireplace?
>
> I've put this question to the Rhino newsgroup and have had some good
> suggestions which I've pasted below:
>
>
>
> HI Steve- I guess it depends upon the density of the screen- if it looks
> like adding too much tiny geometry then you are probably better off with
> scrren texture, but if it's a biggish screen and the views you are
planning
> are close, then geometry might make more sense.
>
> -Pascal
>
>
> Hi Steve,
>
>
> > I'm modeling a wood burning stove that has a screen over its opening.
I'm
> > curious whether I should create a patch surface over the screen and then
> > apply a screen shader, or if I should create a screen type geometry and
> > apply a simple metal shader to the screen.  Any thoughts?
>
> I just completed a screen for a center channel speaker. I wouldn't model
> it in complete 3d or even as a plane with holes. I crashed Rhino trying
> it, just too many surfaces for rhino. But I did create the grill work in
> Rhino using 2d curves, even these became hard to manipulate because you
> will have to make a lot of them to resemble a real screen. I then saved
> the file as .ai and brought it into Photoshop and created a targa image
> that I used as an alpha channel in max.
>
> Sincerely,
> Roland Montijo,
> Rol### [at] aolcom
>
> It looks like I've stumbled over a problem area.  My goal would be to be
> able to see through the screen to the objects inside the stove like the
> grate and maybe a log or two, just as in real life.  It seems that a
shader
> over a surface would be opaque.  Could make a fret work of  small pipes
from
> arrayed lines. Using fewer than normal pipes.   I'm not sure I understand
> the use of the alpha channel and how it might be employed  in Moray which
> I'm using.  Perhaps this is something I should study up on.
>
> Thanks for your thoughts.
>
> later,
> Steve Clarke
> Gresham, Oregon
>
> Hi Steve
>
>
> >>I'm not sure I understand the use of the alpha channel and how it might
be
> employed  in Moray which
> I'm using.  Perhaps this is something I should study up on.<<
>
> Sorry I don't know Moray but perhaps it supports transparency mapping
> someone on this list might know. Basically transparency mapping/alpha
> channeling drops out all the black pixels or whatever pixels you choose
> in a bitmap so that when your rendering program renders the image the
> final rendering lets you see through the applied bitmap where the black
> pixels would be. This ends up saving large amounts of geometry and thus
> rendering faster because you are using a bitmap to supply the
> information.
>
> This is also a technique you see used for outdoor or plant scenes where
> the computer just can't cope with all the millions of leaves.
>
> Sincerely,
> Roland Montijo
> Rol### [at] aolcom
>
> On Wed, 23 Feb 2000 21:47:21 -0800, "Steve Clarke"
> <scl### [at] teleportcom> wrote:
>
> >It looks like I've stumbled over a problem area.  My goal would be to be
> >able to see through the screen to the objects inside the stove like the
> >grate and maybe a log or two, just as in real life.  It seems that a
shader
> >over a surface would be opaque.  Could make a fret work of  small pipes
> from
> >arrayed lines. Using fewer than normal pipes.
>
> To get an idea what Rhino takes cool as a number of pipes see
> attached.
>
> steff
> (attachment not included for sake of bandwidth sc)
>
> Steve Clarke <scl### [at] teleportcom> wrote:
> >...
> > over a surface would be opaque.  Could make a fret work of  small pipes
> from
> > arrayed lines. Using fewer than normal pipes.
> >...
>
> I think you could also just make an array of narrow Plane or 3DFace
> objects. They will be black anyway, right?
> The simpler the screen geometry, the faster it will mesh and render.
>
> -Mikko
>
> Mikko Oksanen
> Robert McNeel & Associates
>
>
>
> Steve,
>
> If your using a renderer that does opacity and displacement mapping.
> You can create a 2d texture of the screen you want and use it as a bump
> map and an opactiy map.  I've done this a lot and it lets you see
> through the holes, and really looks cool.  Plus there's no extra
> geometry to build.
>
> The new version of Bmrt comes with a shader that has that capability.
>
> Maybe an option...
>
> Brian Perry
>
>
>
>

Post a reply to this message

I like the "opacity map", 'image_map' in the case of using POV-Ray, with a
'bump_map' idea the last person had said.
That way you'd just be using a texture by using one premade image put into the
image map and bump map to create the effect.  Real simple.  Something like a
woven cloth pattern perhaps where the spacing is one color for the 'transmit' of
it's index number.  The opaque "threads" being from near black to white for the
bump mapping, giving the screen more 3D depth.  I think the trouble in doing
such a thing (from experience) is the need for plenty of see-through space
otherwise you get only the screening showing.  A fix to that can be to apply
more of a gradient transparency to the "solid" parts of the image map for a
better overall semi-transparency instead of clear and not clear regions.

Bob

Post a reply to this message

Heya- in case you interested, as your use of terminology seems to be slanted
towards programmable shading(ie, programs such as PRMan and BMRT), you may want
to note that there is currently a RIB exporter for Moray available.

Steve Clarke wrote:

> Hello all,
> I'm modeling an interior scene in Rhino 1.1  that contains a small wood
> stove type fireplace.  The stove has a screen over it's opening.  I'm
> debating on whether to create the screen with simple geometry for realism,
> or to find a shader with opacity and displacement mapping.
>
> My question to this group would be: Is there a shader available within
> Moray/povray that would allow me to see through the screen to the interior
> of the fireplace?
>
> I've put this question to the Rhino newsgroup and have had some good
> suggestions which I've pasted below:
>
> HI Steve- I guess it depends upon the density of the screen- if it looks
> like adding too much tiny geometry then you are probably better off with
> scrren texture, but if it's a biggish screen and the views you are planning
> are close, then geometry might make more sense.
>
> -Pascal
>
> Hi Steve,
>
> > I'm modeling a wood burning stove that has a screen over its opening.  I'm
> > curious whether I should create a patch surface over the screen and then
> > apply a screen shader, or if I should create a screen type geometry and
> > apply a simple metal shader to the screen.  Any thoughts?
>
> I just completed a screen for a center channel speaker. I wouldn't model
> it in complete 3d or even as a plane with holes. I crashed Rhino trying
> it, just too many surfaces for rhino. But I did create the grill work in
> Rhino using 2d curves, even these became hard to manipulate because you
> will have to make a lot of them to resemble a real screen. I then saved
> the file as .ai and brought it into Photoshop and created a targa image
> that I used as an alpha channel in max.
>
> Sincerely,
> Roland Montijo,
> Rol### [at] aolcom
>
> It looks like I've stumbled over a problem area.  My goal would be to be
> able to see through the screen to the objects inside the stove like the
> grate and maybe a log or two, just as in real life.  It seems that a shader
> over a surface would be opaque.  Could make a fret work of  small pipes from
> arrayed lines. Using fewer than normal pipes.   I'm not sure I understand
> the use of the alpha channel and how it might be employed  in Moray which
> I'm using.  Perhaps this is something I should study up on.
>
> Thanks for your thoughts.
>
> later,
> Steve Clarke
> Gresham, Oregon
>
> Hi Steve
>
> >>I'm not sure I understand the use of the alpha channel and how it might be
> employed  in Moray which
> I'm using.  Perhaps this is something I should study up on.<<
>
> Sorry I don't know Moray but perhaps it supports transparency mapping
> someone on this list might know. Basically transparency mapping/alpha
> channeling drops out all the black pixels or whatever pixels you choose
> in a bitmap so that when your rendering program renders the image the
> final rendering lets you see through the applied bitmap where the black
> pixels would be. This ends up saving large amounts of geometry and thus
> rendering faster because you are using a bitmap to supply the
> information.
>
> This is also a technique you see used for outdoor or plant scenes where
> the computer just can't cope with all the millions of leaves.
>
> Sincerely,
> Roland Montijo
> Rol### [at] aolcom
>
> On Wed, 23 Feb 2000 21:47:21 -0800, "Steve Clarke"
> <scl### [at] teleportcom> wrote:
>
> >It looks like I've stumbled over a problem area.  My goal would be to be
> >able to see through the screen to the objects inside the stove like the
> >grate and maybe a log or two, just as in real life.  It seems that a shader
> >over a surface would be opaque.  Could make a fret work of  small pipes
> from
> >arrayed lines. Using fewer than normal pipes.
>
> To get an idea what Rhino takes cool as a number of pipes see
> attached.
>
> steff
> (attachment not included for sake of bandwidth sc)
>
> Steve Clarke <scl### [at] teleportcom> wrote:
> >...
> > over a surface would be opaque.  Could make a fret work of  small pipes
> from
> > arrayed lines. Using fewer than normal pipes.
> >...
>
> I think you could also just make an array of narrow Plane or 3DFace
> objects. They will be black anyway, right?
> The simpler the screen geometry, the faster it will mesh and render.
>
> -Mikko
>
> Mikko Oksanen
> Robert McNeel & Associates
>
> Steve,
>
> If your using a renderer that does opacity and displacement mapping.
> You can create a 2d texture of the screen you want and use it as a bump
> map and an opactiy map.  I've done this a lot and it lets you see
> through the holes, and really looks cool.  Plus there's no extra
> geometry to build.
>
> The new version of Bmrt comes with a shader that has that capability.
>
> Maybe an option...
>
> Brian Perry

--
You Know You've Been Raytracing Too Long When:
 You think Windows loads fast.
Produced by Alex Magidow's Sig File Randomizer(YKYBRTTL jokes courtesy of
c.g.r.raytracing)

Post a reply to this message

Alex Magidow <axi### [at] mninternet> wrote in message
news:38B5CCD6.C370CBEA@mninter.net...
> Heya- in case you interested, as your use of terminology seems to be
slanted
> towards programmable shading(ie, programs such as PRMan and BMRT), you may
want
> to note that there is currently a RIB exporter for Moray available.

I'm doing my modeling in Rhino 1.1 and am rendering with Moray/Povray.  I'm
kinda new to the rendering end of things and don't really have a clue toward
getting custom results in this package yet.  But it seems that I should be
able to create a custom shader to my liking with the tools in Moray.

Anyway I've been doing some experimenting with getting a convincing screen
shader and have come up with a few different results.  I hope that this
system can handle a 72.8K attachment. If not I trust someone will tell me
and I won't do it again.

The upper left image is modeled in Rhino and rendered in Moray.  The screen
material, which is the point of all this is a color map texture applied to a
single surface.  Looking for anything that might be close to what I need, I
came across the candy cane texture in the library of textures and modified
it by adding stripes, changing the colors and adding transparency to half of
the stripes, then I changed the noise pattern to granite.  The result is not
what I'm looking for but offers hope that further experimentation will help.

The upper right image is modeled in Rhino and rendered in Moray.  The screen
material is a glass shader applied to a single surface.  I've set the color
to a dark tone and and reduced the reflection.  I don't find this very
distracting and would probably go with it if I don't come up with a better
texture map.

The lower left image is modeled in Rhino and rendered in Rhino.  The screen
material is actual geometry.  I think this looks closest to real, but the
overhead is prohibitive.  I knew this in advance but I wanted to see how
actual geometry would look.  I wonder if I couldnt use this image in
PhotoShop to create a texture map somehow and apply that map to the single
surface while in Moray?

The lower right image is modeled in Rhino and rendered in Rhino.  The screen
material is a single surface with a dark color tone set to it and a
transparency of 40%.  I don't find this distracting either, but have to note
that Rhino is a modeling program.  The rendering function within it is just
to help visualize modeling results.  It is expected by Rhino's creators that
we users will find a suitable renderer.  Which is what brings me here.

Thanks everybody for your input.

later,
Steve




>

Post a reply to this message

Attachments:
Download 'stove comp.jpg' (73 KB)

Preview of image 'stove comp.jpg'

Steve Clarke wrote:

> I hope that this system can handle a 72.8K attachment. If not I
> trust someone will tell me and I won't do it again.

Don't do it again :)

The system can handle it but we prefer that you put binary attachments
like this in the moray.binaries group on this server. After posting it
there you can reference the binary file in your message in this group
so that people know where to find it.

-- 
Ken Tyler - POV-Ray Technical Assistance Group Member

Post a reply to this message

>
> --
> Ken Tyler - POV-Ray Technical Assistance Group Member

Wow! Ken, you have a new title...I think its up to something like, "Uncle
Ken, Thane of links, and King hereafter, cardinal of suggestions, court
jester, and purveyor of POV-Ray And Technical Assistance Group Member"


--
You Know You've Been Raytracing Too Long When:
 You think Windows loads fast.
Produced by Alex Magidow's Sig File Randomizer(YKYBRTTL jokes courtesy of
c.g.r.raytracing)

Post a reply to this message

Alex Magidow wrote:
> 
> >
> > --
> > Ken Tyler - POV-Ray Technical Assistance Group Member
> 
> Wow! Ken, you have a new title...

Couple of months old now. See the official announcement at:

http://home.pacbell.net/tylereng/pov-tag.txt

> I think its up to something like, "Uncle
> Ken, Thane of links, and King hereafter, cardinal of suggestions, court
> jester, and purveyor of POV-Ray And Technical Assistance Group Member"

You left out scullery maid and Chief dish and bottle washer...

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message