How to create 3D images?

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soldevilla
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How to create 3D images?

Post by soldevilla »

Hi.

For a new, exciting work, I must create 3D images of objects that are not too small (5 mm) but that already require stacking of images so that they are completely clear. These 3D images must be able to be exported to my 3D engineering software.
I know that Helicon does this, but perhaps because my license is very old, I don't like the results too much.
Before I start diving on the internet and wasting a lot of time, does anyone have any experience in this and know any software to create these 3D?

Thank you

JH
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Post by JH »

Hi are you thinking of using multiple pictures from different directions or a single stacked picture?
Jörgen Hellberg, my webbsite www.hellberg.photo

David Sykes
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Post by David Sykes »

What do you not like about the results ?
There are a number of problems obtaining left/right views of relatively large subjects if focus stacking is used.
There are not many stack layers so you may get a cardboard cut-out effect.
Secondly,because of the small numerical aperture you will not get many degrees of disparity.
See this very recent thread :-

https://www.photomacrography.net/forum/ ... 72b6820926

The other method is to rotate the specimen about two degrees between shots.
Getting the subject at the centre of rotation could be difficult.
I remember a website detailing how a museum created 3D images of microfossils and the difficulty of specimen manipulation, it is where I first learned of goniometers.
The approach I would take is to rotate the camera around the subject,again just two degrees.

(Hmmm .... I feel a new project coming on :) )

Focus stack each image and use SPM (StereoPhoto Maker) to align the images and correct the keyhole distortion.
You cannot truly correct depth distortion when dealing with toed-in images but it is the best we can do as simply moving the camera sideways is not suitable for macro stereo.
Then use photogrammetry software to create the depth map.

(I know someone in Chile who uses 64 cameras arranged in a circle around the subject and then creates a 3D model,I don’t know if he uses any of the university’s computing resources).

JH
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Post by JH »

For 3D modells from multiple pictures I use Agisoft Metashape. I have a short tutorial on my webpage about photogrammetry. https://www.hellberg.photo/technique/photogrammetry/

Regardless of the size of the subject, stacked pictures or not - make sure you have sharp pictures where every point on the subject is visible in 3 or more pictures.

Two of the models I have posted on the forum

https://www.photomacrography.net/forum/ ... ight=model

https://www.photomacrography.net/forum/ ... ight=model


Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

David Sykes
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Post by David Sykes »

> make sure you have sharp pictures where every point on the subject is visible in 3 or more pictures.

Hmmm ........ I guess subject rotation is definitely required, not attempts at synthetic stereo.

Also, on second thoughts, for subjects as large as 5mm simple,accurate rotation should be OK.

David

soldevilla
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Post by soldevilla »

wow! how much information!
I believe that with a synthetic 3D, created from the deep displacement of the images of a stack, it will give me enough information for what I need.
I have also tested rotating objects and many photos from all angles (an old music disc player is a good platform to start) and then processing those images in a photogrammetry soft. But if I have to do a stack, I hope that with only one stack is enough, I must find a balance between the result and the time consumed.
I do not remember now, but I think I could not open a Helicon file in my CAD software, and that is an essential part of the project, as it would allow us to easily create files for printing on 3D printers. Any problem for do it with the photogrammetry soft...

I need the best parts of the two ways :lol:

PD. Jour Oyster, Jörgen, is simply fantastic. But I feel it take too much time for to do it.

rjlittlefield
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Post by rjlittlefield »

soldevilla wrote:But if I have to do a stack, I hope that with only one stack is enough, I must find a balance between the result and the time consumed.
You should give it a try, just to see. I have seen 3D models built from a single stack, using Zerene Stacker's synthetic rotation to generate two or more views to feed into Agisoft. The ones that I was shown looked useful, not perfect, and their main advantage was that they were constructed from a single stack, of a subject that would have been difficult to rotate physically. I expect that you'd get a better result from physical rotation at larger angles, but then as you say the cost is higher.

--Rik

mawyatt
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Post by mawyatt »

David Sykes wrote:
The other method is to rotate the specimen about two degrees between shots.
Getting the subject at the centre of rotation could be difficult.
I remember a website detailing how a museum created 3D images of microfossils and the difficulty of specimen manipulation, it is where I first learned of goniometers.
The approach I would take is to rotate the camera around the subject,again just two degrees.

(Hmmm .... I feel a new project coming on :) )

.
Here's a note on using a stepper motor to rotate the subject, cheap if you have a spare motor & controller and works surprisingly well with small subjects. :D

https://www.photomacrography.net/forum/ ... t=rotation

Best,
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike

JH
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Post by JH »

soldevilla wrote:wow! how much information!
I believe that with a synthetic 3D, created from the deep displacement of the images of a stack, it will give me enough information for what I need.
I have also tested rotating objects and many photos from all angles (an old music disc player is a good platform to start) and then processing those images in a photogrammetry soft. But if I have to do a stack, I hope that with only one stack is enough, I must find a balance between the result and the time consumed.
I do not remember now, but I think I could not open a Helicon file in my CAD software, and that is an essential part of the project, as it would allow us to easily create files for printing on 3D printers. Any problem for do it with the photogrammetry soft...

I need the best parts of the two ways :lol:

PD. Jour Oyster, Jörgen, is simply fantastic. But I feel it take too much time for to do it.
If your subject does not have:
*hidden surfaces when you look at it from the photo direction.
*reflective surfaces
*transparent surfaces
and if your stack is deep enough for the dept map to contain the depth information you want
and you do not mind the stretched colours on steep areas then you can have a good one sided 3D model from a single stack. This can be done with Helicon Focus, OBJ format, or in Zerene Stacker and processed in Photoshop ,OBJ, U3D PDF and some more formats.

I think that this example might be close to the scale that you want, a single stack, 327 pictures, Canon MPE 65, Zerene Stacker and Photoshop.
https://sketchfab.com/3d-models/mineral ... cb06fdc1ce

This might be more magnification than you want to have, a piece of the same mineral as the example above but with a microscope objective.
https://www.photomacrography.net/forum/ ... 821#229821
https://sketchfab.com/3d-models/mineral ... b2c3260b96

It is outstandingly fast to use Helicon to do this but when I want the scaling to be accurate, I use Photoshop. Left the scaled Zerene stacker – Photoshop picture. Right the Helicon standard 3D (a bit flat in this case). If you have a correct feeling of the scale you can scale the picture manually in Helicon to get a more accurate model.

Image

Hope this helps
Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

JL
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Post by JL »

Hi.

Just by chance, I came across a program called Meshroom, which is open source and, I believe, free.

I watched a couple of videos on Youtube and this is something I may try in the future. Take a look, it might suit you.

https://www.youtube.com/watch?v=k4NTf0hMjtY

soldevilla
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Post by soldevilla »

...or in Zerene Stacker and processed in Photoshop ,OBJ, U3D PDF and some more formats.


:shock: :shock: :shock:

How many doubts generated with so few words! I can´t find how I can use Zerene for this work. maybe I need the "Pro" version? A tutorial somewhere?

I worked a lot with photoshop, but photos, I never imagined its capabilities in 3D. but there are videos and tutorials on the internet, so I'll try to learn. I already ask for help if I not find the right path.

Thanks!!!

rjlittlefield
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Post by rjlittlefield »

soldevilla wrote:I can´t find how I can use Zerene for this work. maybe I need the "Pro" version? A tutorial somewhere?
Jörgen's "how to make a 3D model using Zerene Stacker and Adobe PS", at https://www.photomacrography.net/forum/ ... hp?t=33926 , should help you get started.

Yes, you'll need either Prosumer or Professional Edition to use the "Save depth maps" function beyond that feature's 30-day trial period.

--Rik

soldevilla
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Post by soldevilla »

Gracias, JL

I have a soft for to convert a serie of shots in a 3d model. in fact, I have made some tests with successful outcomes. That part, on one side or the other I think is fixed, I know the least two soft possibilities for to do it, so for now I want to focus on the conversion of a stack into a 3D object

soldevilla
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Post by soldevilla »

In the end I recovered my Helicon license. The soft looks much better 10 years later, although as I thought the resolution is not enough for the 3D I need. Actually on a surface of fairly smooth curves covered by a skin that contains the image and gives it that detailed look. But if the surface is loaded in my CAD software, it doesn't look very good.

I will try photogrammetry ...

JH
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Post by JH »

soldevilla wrote:In the end I recovered my Helicon license. The soft looks much better 10 years later, although as I thought the resolution is not enough for the 3D I need. Actually on a surface of fairly smooth curves covered by a skin that contains the image and gives it that detailed look. But if the surface is loaded in my CAD software, it doesn't look very good.

I will try photogrammetry ...
Using a stack of photos to make a 3D model creates a greyscale depth map. Every photo contributes with one step of grey from black to white. Thus, the number of photos limits the depth resolution. If the photos in the stack is not enough to give you the depth resolution you need, photogrammetry might work. It is quite straight forward using stacked pictures in photogrammetry. I have just added some information about it on my Webb. https://www.hellberg.photo/technique/ph ... -pictures/
My main advices;
-do not change the settings on the camera, lens and, light,
-use diffused light to avoid shadows and
-work step by step - stack a few camera postions put the pictures in a 3D program and se if you get the result you want.

If the combinaton stacking + photgrammetry this does not help the only thing I can think about for 3D models just now is to use a lens with higher resolution.

I am doing some tests using pictures created with Zerene Stackers Stereo/Rocking function. In theroy it should be possible to have a model with more information than with a model from a depth map. Sometimes it works but more often it does not. One main problem is to get the perspective correct. If I get interesting and or usefull results I make a post about it.

Best regards
Jörgen Hellberg
Jörgen Hellberg, my webbsite www.hellberg.photo

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