> Well, the truth about those missing values is more along the profane
> Microsoft lines: They have been reserved for /some/ other fancy mappings
> since so long ago - without ever actually being implemented - that even
> the memory of /what/ mappings those were supposed to be is lost in the
> absorbing and scattering media of time.

Yes, I've had a number of "This Space Reserved" issues.
Now if only I'd taken that 2 seconds to add the comment in the code...

This also makes me wonder of you can map things onto media....  :O


> Worth trying at least.

Touche'.

I've hand coded my ceiling lamps out of spheres, cylinders, cones, and sphere
sweeps, so now I'm going to take a whack at the medallion.  I might see if I
have enough interconnecting brain cells to plot pixels varying in grayscale
value with the sine of the distance from the origin, make that a heightfield,
and then slap my image map onto that...

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Am 10.10.2014 22:04, schrieb Bald Eagle:
>
>
>> Well, the truth about those missing values is more along the profane
>> Microsoft lines: They have been reserved for /some/ other fancy mappings
>> since so long ago - without ever actually being implemented - that even
>> the memory of /what/ mappings those were supposed to be is lost in the
>> absorbing and scattering media of time.
>
> Yes, I've had a number of "This Space Reserved" issues.
> Now if only I'd taken that 2 seconds to add the comment in the code...
>
> This also makes me wonder of you can map things onto media....  :O

Well, you can use patterns to control the density.


>> Worth trying at least.
>
> Touche'.
>
> I've hand coded my ceiling lamps out of spheres, cylinders, cones, and sphere
> sweeps, so now I'm going to take a whack at the medallion.  I might see if I
> have enough interconnecting brain cells to plot pixels varying in grayscale
> value with the sine of the distance from the origin, make that a heightfield,
> and then slap my image map onto that...

Function image, maybe? (You can generate an internal greyscale image 
from a function, and use that as input for a height field.)

Isosurface?

Parametric?

Lathe?

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clipka <ano### [at] anonymousorg> wrote:

> Function image, maybe? (You can generate an internal greyscale image
> from a function, and use that as input for a height field.)

http://www.povray.org/documentation/view/3.6.0/379/
That was an option I was unaware of.  Too much cool stuff to play with!  :)

> Isosurface?
That could totally be a very cool option considering what I've seen people do
with isosurfaces.  Especially since it's a small scene element and so might not
be a huge bottleneck.

> Parametric?
> Lathe?

Both good suggestions I'll have to explore.

With regard to the complex topology of some of the furniture, I'm wondering if
something like a sphere sweep would get me the bulk of what I was aiming for
quickly - especially in the case of the scroll work.  IIRC, there's a "cone
sweep" - is there a cylinder sweep?  blob sweep?
I suppose those are all just specific instances of "follow this spline and plot
this object{X} at the current point", so I could try and code that generalized
case by hand...

Thanks for the suggestions as always.  There are few threads I fail to profit
from in some way.

{Have a great weekend everyone!}

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> Thomas de Groot <tho### [at] degrootorg> wrote:
>
>> Hmm. If considering your image, which is circular, I guess you will need
>> 'once'...
>
> I was thinking that since it's circular, if I had it repeat across the surface
> so that I had 2 full images, each hemispherical, then I could map it onto an
> oblate spheroid and then bury it halfway into the ceiling.
>
> So there.
>
> With regard to blood sacrifice, clipka has slayed the Gamma Dragon, so now
> THAT's not an option.  Somehow Spline Ducks don't quite have the same sense of
> grandeur.  But then..  wait ...  yes!  The Stanford Chocolate Bunny!!!
>
> Bring out the Holy Hand Grenade!
>
Take a simple sphere, unevently scalled, and simply apply your image to 
it as an image_map.
Something like this:

sphere{0, 1 scale <1,1, 0.2>
  pigment{
   image_map{ png "Medaillon1.png" translate -0.5 scale 2}
  rotate 90*x
  rotate y*Light_source_Fudge_Angle
  translate Final_Location
}

As the image is scaled to the same dimention as the sphere, you don't 
need to use once.

Now, you only need to make sure that it's correctly oriented relative 
the dominent light source so that the shadowings are coherent.

A beter way would be to create a hightfield of your medaillon and use 
water_level to cut out the base. That way, the shadows will always be 
correct.




Alain

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> clipka <ano### [at] anonymousorg> wrote:
>
>> Function image, maybe? (You can generate an internal greyscale image
>> from a function, and use that as input for a height field.)
>
> http://www.povray.org/documentation/view/3.6.0/379/
> That was an option I was unaware of.  Too much cool stuff to play with!  :)
>
>> Isosurface?
> That could totally be a very cool option considering what I've seen people do
> with isosurfaces.  Especially since it's a small scene element and so might not
> be a huge bottleneck.
>
>> Parametric?
>> Lathe?
>
> Both good suggestions I'll have to explore.
>
> With regard to the complex topology of some of the furniture, I'm wondering if
> something like a sphere sweep would get me the bulk of what I was aiming for
> quickly - especially in the case of the scroll work.  IIRC, there's a "cone
> sweep" - is there a cylinder sweep?  blob sweep?

No and No.

> I suppose those are all just specific instances of "follow this spline and plot
> this object{X} at the current point", so I could try and code that generalized
> case by hand...
>
> Thanks for the suggestions as always.  There are few threads I fail to profit
> from in some way.
>
> {Have a great weekend everyone!}
>
>

The cone sweep is only for prism. It makes the edges converge toward a 
point. Good to create a pyramid.

In a sphere_sweep, each point require a radius. That radius can be 
negative causing a pinch point in the sweep. OTH, each component can 
only be perfectly spherical, NO scalling of any kind and NO other transform.

For a scroll, one option would be to use a sphere_sweep with components 
having a very small radius, then, to apply very uneven scalling. 
Something like using a radius on 0.001 unit and all points in the same 
plane, then scalling by something like <1,1, 300000>.
If you only give 2D coordinates, the Z coordinate should default to zero.

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On 11-10-2014 22:16, Alain wrote:
> A beter way would be to create a hightfield of your medaillon and use
> water_level to cut out the base. That way, the shadows will always be
> correct.

The drawback of this is that the shadows from the light source are 
incorporated into the height_field. The result may not be what you expect.

Thomas

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> On 11-10-2014 22:16, Alain wrote:
>> A beter way would be to create a hightfield of your medaillon and use
>> water_level to cut out the base. That way, the shadows will always be
>> correct.
>
> The drawback of this is that the shadows from the light source are
> incorporated into the height_field. The result may not be what you expect.
>
> Thomas
>
>

I should have precised that the hight_field should be made from another 
source image. That image should not rely on any light source to show the 
relief.

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OK, after I got that all squared away, I worked out a shape that very closely
approximates the curvature of the actual medallion, and then after some further
frustration in trying to get THAT mapped it looks pretty good.

Left and top is the hemispheroid, and right, center, and bottom are the modeled
medallion shape.

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Attachments:
Download 'medallionfunction.png' (143 KB)

Preview of image 'medallionfunction.png'

On 13-10-2014 3:10, Bald Eagle wrote:
> OK, after I got that all squared away, I worked out a shape that very closely
> approximates the curvature of the actual medallion, and then after some further
> frustration in trying to get THAT mapped it looks pretty good.
>
> Left and top is the hemispheroid, and right, center, and bottom are the modeled
> medallion shape.
>

Yes, this will certainly do indeed.

Thomas

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Fireplace Mantel modeled in SDL.
Still needs a bit of touch-up.

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Attachments:
Download 'mantel.png' (248 KB)

Preview of image 'mantel.png'