Thomas de Groot <tho### [at] degrootorg> wrote:

> I did my transformations (on the original converted OBJ files) in
> Poseray, centering and then rotating the vase, and dropping it to y=0,
> /before/ exporting to POV-Ray.

I didn't play a lot with Poseray once I got the file converted.
I wanted all the subsequent processing to be done in a way that's easily traced
(SDL) and preserved the raw data.  But the sweet textured renders of the
processed mesh are nice and really show the results possible with POV-Ray and
granite_21   :)

https://sketchfab.com/3d-models/pre-dynastic-egyptian-vase-9d0564976fec4d718aca1d661cec212a


Did you do your transformations by eye/feel?
My -z rotation was based on some trace() results on the lug handles, followed by
some atan2 () hocus-pocus that I'm calling good-enough for now.



> In my studio set-up I used trace {} to put the vase on the 'pedestal'.
> The 'base' of the vase effectively is situated at y=0 in the geometry file.


The bounding box that Poseray assigns to the vase seems fine heightwise, but
overly wide, so getting it to sit at y=0 was fairly straightforward.
I'm wondering what Poseray and Meshlab, and even Matlab have for mesh-feature
analysis tools.

I'm guessing that Polyworks has all the pricey bells and whistles for
identifying such features and fitting planes, spheres and cones in a
least-squares best-fit fashion to a model.

Maybe I need to slice the vas at the lug handle hole and inspect the mesh at a
high magnification to see why I'm not getting good trace() results.

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Op 27-2-2023 om 12:47 schreef Bald Eagle:
> Thomas de Groot <tho### [at] degrootorg> wrote:
> 
>> I did my transformations (on the original converted OBJ files) in
>> Poseray, centering and then rotating the vase, and dropping it to y=0,
>> /before/ exporting to POV-Ray.
> 
> I didn't play a lot with Poseray once I got the file converted.
> I wanted all the subsequent processing to be done in a way that's easily traced
> (SDL) and preserved the raw data.  But the sweet textured renders of the
> processed mesh are nice and really show the results possible with POV-Ray and
> granite_21   :)
> 
Sure!

>
https://sketchfab.com/3d-models/pre-dynastic-egyptian-vase-9d0564976fec4d718aca1d661cec212a
> 
> 
> Did you do your transformations by eye/feel?
> My -z rotation was based on some trace() results on the lug handles, followed by
> some atan2 () hocus-pocus that I'm calling good-enough for now.
> 
No. I let Poseray give me the necessary values and acted on them.


>> In my studio set-up I used trace {} to put the vase on the 'pedestal'.
>> The 'base' of the vase effectively is situated at y=0 in the geometry file.
> 
> 
> The bounding box that Poseray assigns to the vase seems fine heightwise, but
> overly wide, so getting it to sit at y=0 was fairly straightforward.

You think so? Once rendered, I do not see any significant width 
difference compared to the STL original.

> I'm wondering what Poseray and Meshlab, and even Matlab have for mesh-feature
> analysis tools.
> 
> I'm guessing that Polyworks has all the pricey bells and whistles for
> identifying such features and fitting planes, spheres and cones in a
> least-squares best-fit fashion to a model.
> 
> Maybe I need to slice the vas at the lug handle hole and inspect the mesh at a
> high magnification to see why I'm not getting good trace() results.
> 
Just wondering: did you try to trace the model while still on its side? 
I have not been trying that so I wouldn't know indeed about bounding box 
issues there.

-- 
Thomas

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On 27/02/2023 12:25, Thomas de Groot wrote:
> And the same from the 'optimized' version (note that for some reason, 
> the size is much larger. yesbird?):

Perhaps ZBrush doing rescale while importing and optimization, in any
case applying 'scale' should not me a problem, I suppose.
--
YB

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On 27/02/2023 12:25, Thomas de Groot wrote:
> And the same from the 'optimized' version (note that for some reason, 
> the size is much larger. yesbird?):

Perhaps ZBrush does rescale while importing and/or optimizing, in any
case applying 'scale' before rendering should not be a problem, I suppose.
--
YB

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hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> ...
> Yeah - I did an intersection to slice it in half, and was wondering what all
> that was about.  Might be just poor mesh structure due to conversion from a raw
> point cloud / stl-obj-pov .... ?

in the stl data, I guess.  although TdG uses different OS and tools, both meshes
have the same "shadows".


regards, jr.

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This makes me curious....

https://polyworks.software.informer.com/12.0/

Anyone willing to give it a go?

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Op 27-2-2023 om 15:15 schreef yesbird:
> On 27/02/2023 12:25, Thomas de Groot wrote:
>> And the same from the 'optimized' version (note that for some reason, 
>> the size is much larger. yesbird?):
> 
> Perhaps ZBrush doing rescale while importing and optimization, in any
> case applying 'scale' should not me a problem, I suppose.
> -- 
> 
I guessed that to be the case indeed, and no, it is not a problem by 
itself. However, it is good to be aware of this especially if the goal 
is to recreate a 1:1 scale model.

-- 
Thomas

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Op 27-2-2023 om 13:19 schreef Thomas de Groot:
> Op 27-2-2023 om 12:47 schreef Bald Eagle:
>> The bounding box that Poseray assigns to the vase seems fine 
>> heightwise, but
>> overly wide, so getting it to sit at y=0 was fairly straightforward.
> 
I forgot to mention in my earlier comment that in Poseray I generally 
start (in the Groups window) on a new model:

1- 'Weld vertices'
2- 'Remove orphan vertices'
3- 'Recalculate normals'

without changing 'Crease angle' or 'Tolerance'.

If stray vertices exist, the bounding box may thus be improved.

Then, I do the transforms I deem necessary for my subsequent use in 
POV-Ray. Poseray is very efficient for this although you may have to 
play a bit with the application before you get it right.

-- 
Thomas

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Update:

A link to this detailed analysis of the vase has just been posted.

https://unsigned.io/granite-artifact/

I'll be out to work and then doing things this afternoon, but maybe if others
are interested, they can read, play with it, write some macros and scenes, etc.

- BW

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Op 27-2-2023 om 03:22 schreef Bald Eagle:
> Height is 4.72 inches
> Radius of body is 1.67 inches
> 

Ok. I used this to apply to the vase in my studio setup.

1- I converted inches to centimeters
2- I used the following code by Alain to scale the vase to POV-unit scale:
 
http://news.povray.org/povray.newusers/thread/%3C60c8e000%241%40news.povray.org%3E/
3- I scaled the object the object to Real World sizes

The result is attached. Note that the grid on the pedestal is a 1 meter 
square corresponding to 1 POV-unit. Subdivisions in 10 centimeter 
squares. The grid was applied as an object pattern to the texture of the 
pedestal.

-- 
Thomas

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Attachments:
Download 'predynastic_vase_06.jpg' (58 KB)

Preview of image 'predynastic_vase_06.jpg'