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I've got a fairly elaborate problem in my project that I'm working on
with a couple of co-students at the university. We're digitally
reconstructing a castle and have a few towers with cone-tipped roofs or
even onion-shaped (looking much like those arabic and/or indian
tower-roofs)...
Anyways, I've got a rectangular, tileable slate roof texture, and my
idea was to create a bunch of single shingles, map them onto prisms or
triangles/quads, and write a script which'll follow the shape of the
roofs, place an appropriate amount of shingles based on the
circumferance, move on to the next row... Until the roof is finished.
I'd then render a top-view of the result and project that back onto the
original cone.
This will work fine for those towers that actually have a cone as a
roof, those that have onions will have a projection problem on places
where the roof is nearly vertical. I began wondering if it might be
possible to render a cylindrical view of the towers, but not from the
inside out, instead, from the outside (a certain distance) towards the
center. I thus would get a cylindrical texture I can map back onto the
onion shape with little less stretching issues...
Anyone have a clue about how I might achieve that with POV-Ray (just
rendering that cylindrical view, everything else I can pretty much
script myself)? I'm dimly remembering that there was once a patched
POV-Ray which would allow functions as input for the camera, I'm
wondering if I'd need that (and if anyone has a suitable function
already at hand, I'm not that good with those)...
Regards,
Tim
PS: Just re-reading this post for errors and misspelling, I was
wondering if I could use the basic cylindrical rendering POV-Ray
provides, but simply switch the roof-tiles to no_image, place a
reflecting cylinder outside the roof, and thus, render the reflection
*as if* I was looking from the outside... Hm, worth a shot, at least...
--
aka "Tim Nikias"
Homepage: <http://www.nolights.de>
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Tim Nikias nous apporta ses lumieres en ce 10/11/2006 13:21:
> I've got a fairly elaborate problem in my project that I'm working on
> with a couple of co-students at the university. We're digitally
> reconstructing a castle and have a few towers with cone-tipped roofs or
> even onion-shaped (looking much like those arabic and/or indian
> tower-roofs)...
> Anyways, I've got a rectangular, tileable slate roof texture, and my
> idea was to create a bunch of single shingles, map them onto prisms or
> triangles/quads, and write a script which'll follow the shape of the
> roofs, place an appropriate amount of shingles based on the
> circumferance, move on to the next row... Until the roof is finished.
> I'd then render a top-view of the result and project that back onto the
> original cone.
Why that extra step? Your script can place your individual shingles/tiles
directly onto your roofs.
> This will work fine for those towers that actually have a cone as a
> roof, those that have onions will have a projection problem on places
> where the roof is nearly vertical. I began wondering if it might be
> possible to render a cylindrical view of the towers, but not from the
> inside out, instead, from the outside (a certain distance) towards the
> center. I thus would get a cylindrical texture I can map back onto the
> onion shape with little less stretching issues...
> Anyone have a clue about how I might achieve that with POV-Ray (just
> rendering that cylindrical view, everything else I can pretty much
> script myself)? I'm dimly remembering that there was once a patched
> POV-Ray which would allow functions as input for the camera, I'm
> wondering if I'd need that (and if anyone has a suitable function
> already at hand, I'm not that good with those)...
> Regards,
> Tim
> PS: Just re-reading this post for errors and misspelling, I was
> wondering if I could use the basic cylindrical rendering POV-Ray
> provides, but simply switch the roof-tiles to no_image, place a
> reflecting cylinder outside the roof, and thus, render the reflection
> *as if* I was looking from the outside... Hm, worth a shot, at least...
Did you try cylindrical warp? spherical warp?
You also can use trace to place your tiles on the conical and onion shaped roofs
and do away with texture maping.
--
Alain
-------------------------------------------------
Don't take life too seriously, you won't get out alive.
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Alain wrote:
> Did you try cylindrical warp? spherical warp?
That's more or less what I was getting at with the uv-mapping. Let's
just say the texture has 20 tiles along the x-axis. There'd be 20 tiny
tiles at the top of the cone, and 20 large tiles at the bottom. But
tiles are usually about the same size, so I can't use a warp to stretch
the texture to fit the cone.
> You also can use trace to place your tiles on the conical and onion
> shaped roofs and do away with texture maping.
That's what I was aiming at: scripting the placement of tiles, but
*then* I need to rebake that into a texture to apply it to a polygon
model...
I guess I forgot to mention in my original post that the castle is
modelled in Maya and will be rendered with Mental Ray, and the PCs we
have for the task are barely able to load the scene as it is, I can't
throw another couple thousand poly's in there just for a few tiles.
Thus, I want to create the roof with script in POV-Ray, and render the
resulting placement of tiles to an image I can use as a texture to
project onto the polygons in Maya. A little complicated and probably
somehow possible within Maya, but I've been getting fed up with the
"professional" standard-crashing piece of software that I'd rather turn
to a rock-solid freeware raytracer to do the task painlessly. :-)
Regards,
Tim
--
aka "Tim Nikias"
Homepage: <http://www.nolights.de>
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Tim Nikias nous apporta ses lumieres en ce 10/11/2006 18:06:
> Alain wrote:
>> Did you try cylindrical warp? spherical warp?
> That's more or less what I was getting at with the uv-mapping. Let's
> just say the texture has 20 tiles along the x-axis. There'd be 20 tiny
> tiles at the top of the cone, and 20 large tiles at the bottom. But
> tiles are usually about the same size, so I can't use a warp to stretch
> the texture to fit the cone.
>> You also can use trace to place your tiles on the conical and onion
>> shaped roofs and do away with texture maping.
> That's what I was aiming at: scripting the placement of tiles, but
> *then* I need to rebake that into a texture to apply it to a polygon
> model...
> I guess I forgot to mention in my original post that the castle is
> modelled in Maya and will be rendered with Mental Ray, and the PCs we
> have for the task are barely able to load the scene as it is, I can't
> throw another couple thousand poly's in there just for a few tiles.
> Thus, I want to create the roof with script in POV-Ray, and render the
> resulting placement of tiles to an image I can use as a texture to
> project onto the polygons in Maya. A little complicated and probably
> somehow possible within Maya, but I've been getting fed up with the
> "professional" standard-crashing piece of software that I'd rather turn
> to a rock-solid freeware raytracer to do the task painlessly. :-)
> Regards,
> Tim
You can create shingles with as few as 4 polys: a square for the top and front
and 2 triangles for the edges, or using a mesh of 6 triangles. It's possible as
you never see the under side. In POV-Ray, a mesh is only referenced, so it only
takes a minimal amount of memory to have even 1000000 instances.
--
Alain
-------------------------------------------------
Church of SubGenius: BoB shits.
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Alain wrote:
> You can create shingles with as few as 4 polys: a square for the top and
> front and 2 triangles for the edges, or using a mesh of 6 triangles.
> It's possible as you never see the under side. In POV-Ray, a mesh is
> only referenced, so it only takes a minimal amount of memory to have
> even 1000000 instances.
Ahem, I know all that. I'm using Autodesk's Maya 8 for everything, I
just want to create a texture for the roofs made up of a couple dozen
polys, instead of thousands. And Maya is such a PITA that I don't want
to clutter the scene with hundreds of instances of a small mesh. Thus, I
want to render a texture.
Think of it as a 3D-Game-Engine-Object, you don't want to place
thousands of small objects into a game just for a roof.
Regards,
Tim
--
aka "Tim Nikias"
Homepage: <http://www.nolights.de>
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Tim Nikias nous apporta ses lumieres en ce 11/11/2006 02:47:
> Alain wrote:
>> You can create shingles with as few as 4 polys: a square for the top
>> and front and 2 triangles for the edges, or using a mesh of 6
>> triangles. It's possible as you never see the under side. In POV-Ray,
>> a mesh is only referenced, so it only takes a minimal amount of memory
>> to have even 1000000 instances.
> Ahem, I know all that. I'm using Autodesk's Maya 8 for everything, I
> just want to create a texture for the roofs made up of a couple dozen
> polys, instead of thousands. And Maya is such a PITA that I don't want
> to clutter the scene with hundreds of instances of a small mesh. Thus, I
> want to render a texture.
> Think of it as a 3D-Game-Engine-Object, you don't want to place
> thousands of small objects into a game just for a roof.
> Regards,
> Tim
If all you want is maya oriented tips, then you are in the wrong group.
One thing that you can do, is to model in maya, then export and render in
POV-Ray. Take a look at poseray, it can convert many formats into POV format.
--
Alain
-------------------------------------------------
There will always be beer cans rolling on the floor of your car when the boss
asks for a ride home from the office.
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Alain wrote:
> If all you want is maya oriented tips, then you are in the wrong group.
Hehe, see below. :-)
> One thing that you can do, is to model in maya, then export and render
> in POV-Ray. Take a look at poseray, it can convert many formats into POV
> format.
I figured it out, and I'll explain it. I guess you've been
misunderstanding me all the time, or I was writing cryptic...
I export the roof-mesh to POV-Ray and then use a script to place
shingles onto it, placing hundreds of them and thus get a nice, slated
roof - all inside POV-Ray.
I put the camera inside the roof, viewing outwards, and set all tiles to
no_image. There's a large cylinder around the roof, which does nothing
else than reflecting.
Thus, when my cylindrical camera looks outward, I see the roof as if
from the outside (no_image-Objects show up in reflections). The
resulting render I can use for a cylindrical mapping inside Maya.
My problem was to set the camera to cylindrical and ensuring that I see
all 360 degrees around me, otherwise the texture wouldn't line up at the
seams.
Basically, I was after rendering a cylindrical texture to map onto the
roof, how to model everything wasn't the issue. Guess I went about
explaining it the wrong way round. :-) Hope I didn't annoy you too much.
Regards,
Tim
--
aka "Tim Nikias"
Homepage: <http://www.nolights.de>
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Alain wrote:
> If all you want is maya oriented tips, then you are in the wrong group.
> One thing that you can do, is to model in maya, then export and render
> in POV-Ray. Take a look at poseray, it can convert many formats into POV
> format.
FYI, Tim has been around for many years, he is not a new users of POV-Ray ;-)
Thorsten
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> I began wondering if it might be
> possible to render a cylindrical view of the towers, but not from the
> inside out, instead, from the outside (a certain distance) towards the
> center.
I see that you already solved your problem, so just for the record:
I once had the same need. My first solution was to patch povray. Then I
came up with the following more portable one: Use a cylindrical camera,
shift it along the axis of rotation away from the object and use two
conical (with height=radius) mirrors to bring the rays of vision back to
the object.
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Mark Weyer wrote:
>> I began wondering if it might be
>> possible to render a cylindrical view of the towers, but not from the
>> inside out, instead, from the outside (a certain distance) towards the
>> center.
>
> I see that you already solved your problem, so just for the record:
>
> I once had the same need. My first solution was to patch povray. Then I
> came up with the following more portable one: Use a cylindrical camera,
> shift it along the axis of rotation away from the object and use two
> conical (with height=radius) mirrors to bring the rays of vision back to
> the object.
Hm, could you post the code for that? Just because I'm curious, my
solution was different (and IMHO a little more intuitive):
All the objects in question are set to "no_image" and the camera looks
at the inside of a 100% reflective cylinder, thus the rays get reflected
back onto the outside surface (and with "no_image", objects show up in
reflections) and I get the view I want.
Regards,
Tim
--
aka "Tim Nikias"
Homepage: <http://www.nolights.de>
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