Now, how would you explain this?

I turned the models 90 degrees: we are looking along the x-axis of the 
object to visualize.

Thomas

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Download 'gt_df3_test.png' (108 KB) Download 'makedf3object_.png' (40 KB)

Preview of image 'gt_df3_test.png'

Preview of image 'makedf3object_.png'

Le 28/09/2013 17:02, Thomas de Groot nous fit lire :
> Now, how would you explain this?
> 
> I turned the models 90 degrees: we are looking along the x-axis of the
> object to visualize.
> 
> Thomas

what is strange ?
The df3 describes a unit-cube, with distinct resolution along each axis,
but it is only a unit-cube.

So, with such model, you need a scale around 3 or so along the vertical
axis on the field to restore the kind of posture you had on the original.

Or did I missed again some red circle ?

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Now, how would you explain this?
>
> I turned the models 90 degrees: we are looking along the x-axis of the
> object to visualize.
>
> Thomas

Hi Thomas,

I can only guess your problem, but I think you are missing some structure (e.g.
the ribs) here.

May be you can try a higher resolution. I use the following ini-file for my
ghost (just running for another pose):

Antialias=Off
;Input_File_Name=ctdress_.pov
Input_File_Name=cteyes_.pov
;Input_File_Name=cthaare_.pov
;Input_File_Name=ctkleid_.pov

Height=512
Width=512

Initial_Frame=1
Final_Frame=512
;Subset_Start_Frame=1
;Subset_End_Frame = 120
Initial_Clock=0
Final_Clock=1

Output_File_Type=T

Best regards,
Michael

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On 28-9-2013 17:19, Le_Forgeron wrote:
> what is strange ?
> The df3 describes a unit-cube, with distinct resolution along each axis,
> but it is only a unit-cube.

Well, /that/ is exactly what I am wondering. Does the df3 /always/ scale 
to the unit-sized box? whatever the bounding box of the object is? I 
probably missed something but I do not remember having read this anywhere.

That puts my earlier observation of squeezing into another light...

>
> So, with such model, you need a scale around 3 or so along the vertical
> axis on the field to restore the kind of posture you had on the original.

No, more probably along the z-axis as that is visibly stretched out.

>
> Or did I missed again some red circle ?

<grin> no.

Thomas

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On 28-9-2013 17:23, MichaelJF wrote:
> I can only guess your problem, but I think you are missing some structure (e.g.
> the ribs) here.

I know. That is a resolution problem most probably. My wondering was 
about the stretching along the z-axis of the df3 compared to the 
original model. I later guessed (and Le_Forgeron confirmed) that df3 
files scale to the unit-sized box which I had not been aware of at all. 
By chance my first test was with an almost spherical object ;-)

If so, it makes the use of df3 files from selected objects a bit more 
tricky to use, I mean, an extra transformation is needed, back to the 
original bounding box size using min_ and max_extent.

Thomas

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Le 29/09/2013 09:01, Thomas de Groot nous fit lire :
> On 28-9-2013 17:19, Le_Forgeron wrote:
>> what is strange ?
>> The df3 describes a unit-cube, with distinct resolution along each axis,
>> but it is only a unit-cube.
> 
> Well, /that/ is exactly what I am wondering. Does the df3 /always/ scale
> to the unit-sized box? whatever the bounding box of the object is? I
> probably missed something but I do not remember having read this anywhere.
> 
> That puts my earlier observation of squeezing into another light...
> 

Citing 3.6 documentation, first sentence:
> http://www.povray.org/documentation/view/3.6.1/374/

The density_file pattern is a 3-D bitmap pattern that occupies a unit
cube from location <0,0,0> to <1,1,1>.

**********

The same sentence was already in 3.1 documentation

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On 29-9-2013 10:12, Le_Forgeron wrote:

> Citing 3.6 documentation, first sentence:
>> http://www.povray.org/documentation/view/3.6.1/374/
>
> The density_file pattern is a 3-D bitmap pattern that occupies a unit
> cube from location <0,0,0> to <1,1,1>.
>
> **********
>
> The same sentence was already in 3.1 documentation

Which confirms my diffuse reading.... ;-)

Thomas

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There is still something that I do not understand.

I have now scaled back the df3 files, using for a defined object Obj:

#local Min   = min_extent(Obj);
#local Max   = max_extent(Obj);
#local Size  = Max-Min;

Superposing the object and the df3 files, flipping the df3 files along y 
(Gilles Tran), and resizing the df3 files, I note the following:

1) the x-axis needs also to be flipped! Visible especially with 
asymmetrical objects (skeleton)
2) the skeleton df3 needs an additional x-axis scale correction: scale 
<-3.0,-1,1>*Size
3) the head df3 needs a /different/ x-axis scale correction: scale 
<-2.3,-1,1>*Size

The two images show orthographic views.

Question: If the df3 are made to a unit-sized box, why does the x-axis 
need a correction different from object to object?

Thomas

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Preview of image 'gt_df3_test_1.jpg'

Preview of image 'gt_df3_test_2.jpg'

On 29-9-2013 14:02, Thomas de Groot wrote:

> Question: If the df3 are made to a unit-sized box, why does the x-axis
> need a correction different from object to object?

A tentative answer to the question:

Could it be that the image format in which the tga slices are rendered 
influences the final result? In other words, should objects be rendered 
using a /square/ image format (1:1 ratio) in the first place? I blindly 
followed Gilles Tran's advice to use a 1.33 ratio. This might be 
irrelevant for clouds but not for other objects...

Thomas

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Le 29/09/2013 14:27, Thomas de Groot nous fit lire :
> On 29-9-2013 14:02, Thomas de Groot wrote:
> 
>> Question: If the df3 are made to a unit-sized box, why does the x-axis
>> need a correction different from object to object?
> 
> A tentative answer to the question:
> 
> Could it be that the image format in which the tga slices are rendered
> influences the final result? In other words, should objects be rendered
> using a /square/ image format (1:1 ratio) in the first place? I blindly
> followed Gilles Tran's advice to use a 1.33 ratio. This might be
> irrelevant for clouds but not for other objects...
> 
> Thomas
> 
Do we have the sources of tga2df3 ?

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