Hi,
   I need to make a filled height field, that is, a height field which 
has an interior beneath the top surface.

I've been looking and the height_field cannot do this in my 
understanding, possibly an isosurface could, but you can probably 
compare my skills to a newbies'!

If not possible I was thinking on tracing the hf and put a sphere and a 
cylinder from there to y=-1...  this would be extremely memory exaustive 
and would probably end up being impossible with my hardware.  I need a 
very big precision hf, I could possibly then try with a low res hf, make 
the same thing with cylinders in a blob and then apply a normal texture 
or a bump_map of some sort to give more precision?

But I really don't know what is the best thing I should do!

Thanks for any help!
   Xilo

-- 
Dedicated to audio/visual and interactive artwork.
http://www.geocities.com/simonlemieux/

Post a reply to this message

Xilo Musimene <xil### [at] hotpopcom> wrote:
>    I need to make a filled height field, that is, a height field which 
> has an interior beneath the top surface.

  You should be more specific about this. You description does not really
tell what is what you need.
  Can you, for example, post a small scene showing the unwanted effect and
then describing how you would like that image to look like?

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

Post a reply to this message

In article <3ED### [at] hotpopcom>,
 Xilo Musimene <xil### [at] hotpopcom> wrote:

>    I need to make a filled height field, that is, a height field which 
> has an interior beneath the top surface.

A height_field object does have an interior, as I recall it extends from 
the surface infinitely in the -y direction. It just doesn't have any 
sides, which makes it tricky to use for things like media.


> If not possible I was thinking on tracing the hf and put a sphere and a 
> cylinder from there to y=-1...  this would be extremely memory exaustive 
> and would probably end up being impossible with my hardware.  I need a 
> very big precision hf, I could possibly then try with a low res hf, make 
> the same thing with cylinders in a blob and then apply a normal texture 
> or a bump_map of some sort to give more precision?

I don't know what you're talking about here, but it sounds like you are 
making things much too complex. Just use an intersection of the height 
field with a box...scale and translate the height field to slightly 
overlap the sides of the box (to avoid precision problems), and you will 
get a shape with the sides of the box and the upper surface of the 
height field.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message

"Warp" <war### [at] tagpovrayorg> wrote in message
news:3ed7dca0@news.povray.org...
> Xilo Musimene <xil### [at] hotpopcom> wrote:
> >    I need to make a filled height field, that is, a height field which
> > has an interior beneath the top surface.
>
>   You should be more specific about this. You description does not really
> tell what is what you need.

Well, CSG difference from a box could be the answer. That gives a solid
object to work with. But I agree that the Xilo's message confused me when it
came to the cylinders and blobs and bump mapping.

Bob H.

Post a reply to this message

>   You should be more specific about this. You description does not really
> tell what is what you need.
>   Can you, for example, post a small scene showing the unwanted effect and
> then describing how you would like that image to look like?
> 

Ok, I'll post what I mean in p.b.images as "Fill Height field"

Xilo

-- 
Dedicated to audio/visual and interactive artwork.
http://www.geocities.com/simonlemieux/

Post a reply to this message

Hughes, B. <omn### [at] charternet> wrote:
> Well, CSG difference from a box could be the answer.

  Perhaps you mean the intersection of the heightfield and a box { 0,1 }?

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -

Post a reply to this message

In article <3ED### [at] hotpopcom>,
 Xilo Musimene <xil### [at] hotpopcom> wrote:

> Ok, I'll post what I mean in p.b.images as "Fill Height field"

I didn't say to scale the height field to overlap the box just to make 
it more challenging. The speckles should be a dead giveaway: you are 
seeing an equivalent to the coincident surface problem, sometimes the 
sides of the box are "inside" the height field, sometimes they are 
"outside", depending on how the precision errors turn out.

intersection {
    box { <-0.5, -0.5, -0.5>, <0.5, 1, 0.5>}
    height_field { png "Heightfield.png" smooth
        scale < 1.02, 0.1, 1.02>
        translate <-0.51, 0, -0.51>
    }
    pigment {rgb 1}
}


> // or perhaps: plane { <0,1,0>, 3 }

No, that will not work. You are adding sides, a plane doesn't have sides.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message

"Warp" <war### [at] tagpovrayorg> wrote in message
news:3ed7f561@news.povray.org...
> Hughes, B. <omn### [at] charternet> wrote:
> > Well, CSG difference from a box could be the answer.
>
>   Perhaps you mean the intersection of the heightfield and a box { 0,1 }?

No, I meant difference alright, I just spoke too soon. That would require a
box having an inverse keyword added to it. CSG intersection doesn't always
seem to do what I think it's going to do so I just acquired a habit of
avoiding it if I think there might be confusion. My mistake to suggest CSG
difference.

Glad scaling was also told of concerning this, as I read elsewhere, I had
neglected to mention it. Although, I am not sure anyone said scaling of a
box {0,1} will leave three sides unaffected due to the <0,0,0> corner.
Bottom, left and front, as viewed with a typical camera. The height_field
and box should be centered on <0,0,0> to make that easier preventing the
coincident surfaces.

Bob H.

Post a reply to this message

> I didn't say to scale the height field to overlap the box just to make 
> it more challenging. The speckles should be a dead giveaway: you are 
> seeing an equivalent to the coincident surface problem, sometimes the 
> sides of the box are "inside" the height field, sometimes they are 
> "outside", depending on how the precision errors turn out.
> 
> intersection {
>     box { <-0.5, -0.5, -0.5>, <0.5, 1, 0.5>}
>     height_field { png "Heightfield.png" smooth
>         scale < 1.02, 0.1, 1.02>
>         translate <-0.51, 0, -0.51>
>     }
>     pigment {rgb 1}
> }

Ok, but I changed the box to look like this:
box { <-0.6, -0.5, -0.6>, <0.6, 1, 0.6>}

And the picture was exactly the same...

>>// or perhaps: plane { <0,1,0>, 3 }
> 
> 
> No, that will not work. You are adding sides, a plane doesn't have sides.

Well, I just want it filled so I can do difference on it and carve 
things into my height field...

Thanks,
   Xilo

-- 
Dedicated to audio/visual and interactive artwork.
http://www.geocities.com/simonlemieux/

Post a reply to this message

In article <3ED### [at] hotpopcom>,
 Xilo Musimene <xil### [at] hotpopcom> wrote:

> Ok, but I changed the box to look like this:
> box { <-0.6, -0.5, -0.6>, <0.6, 1, 0.6>}
> 
> And the picture was exactly the same...

I doubt that...you avoided the coincidence problem by putting the box 
sides outside the height field, exactly the opposite of what will work, 
so you probably didn't even get the speckled sides at the back. Try 
following the instructions given. Jeez, I even gave you working example 
code...


> > No, that will not work. You are adding sides, a plane doesn't have sides.
> 
> Well, I just want it filled so I can do difference on it and carve 
> things into my height field...

As explained, the height field is already a solid object, it just 
doesn't have sides. If you want solid sides instead of just the upper 
surface, you need to intersect it with a slightly smaller box so the 
sides of the box will be used. The plane you used doesn't have any 
surfaces that can be used for the sides, so intersecting with it will 
not work. In fact, it didn't have *any* surfaces that intersected the 
height field, so the only effect would have been to make the height 
field render slower. You could intersect with 4 planes perpendicular to 
the height field, one for each side, but this will be both slower and 
more work to set up.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message