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Fish and objects with changing geometry

Artec Space Spider

[updated on 26 March 2018]

We were given a dried specimen of this Diodone fish with a question "Can you 3D-scan this one?"
As you see from the screenshots, the answer is yes :) The result 3D model is available for download here. Additionally, feel free to check it here on Sketchfab as well as to review some extra 3D-scanning and processing information below.

  

Our setup:

  • Coloured background with pattern works as an excellent texture feature here!
  • The fish is placed on a transparent stand on purpose - it is not visible for the scanner, i.e. it is not recorded and the background can be easily removed during post-processing with an Eraser in a couple of clicks.

setup1.JPG 

Scan data:

  • Overall there are 5 scans with about 5700 raw 3D-frames in total.
  • Such amount of frames was recorded to capture these long spines over the fish body from all possible angles.
  • No spray or something of this kind was used, just Artec Space Spider and Artec Studio 12.

setup_2.JPG

 

 

Artec Eva

[updated on 08 March 2015]

We scanned this fish with an Artec Eva back in 2015, when our team was asked to develop a fish-scanning technique for one of our clients. An interesting request I should say! :) Feel free to download the result 3D model here

 

Trick 1: hang the fish in the air

Since the fish can be referred to the objects with changing geometry, the easiest way to capture is to hang it in the air, so it becomes to capture it from all angles. For example, hang it on a string! The major advantage of this method is that the fish will rotate and you won't need to walk around it with the scanner.

Here is a short video, illustrating the process:

 

Trick 2: put the fish on a glass

The reason beyond this recommendation is that you will be able to easily capture the fish from below, i.e. through the glass.

You will need a reference object for a smooth transition from the underside to the upperside. Also, it will be beneficial for alignment, in case you capture several raw scans during this session.

 

Trick 3: use non-rigid alignment

Overall, this method is excellent for scanning soft objects with simple geometry. Non-rigid alignment algorithm (NRA) is extremely useful, when any object (a person, a fish, etc) moved or changed a shape between scanning session. The less the object changes its shape between your scanning sessions - the better.

Workflow:

  • Make several scans and run the Fine, Global and Fusion algorithms on each of them separately
  • Select all fusions in Workspace, navigate to Align section and select Non-Rigid Alignment tab
  • Mark the fusion, which you want to leave unchanged, as registered, then align all other fusions relative to it
  • To speed up the process, you can erase some overlapping geometry, but try not to erase too much
  • At the end of NRA, all of your fusions will have a similar shape
  • The last step is to run "fusion of fusions", so you will merge your data together. Sharp fusion with a small resolution parameter (0.5 or 0.8 mm) is preferable in this case

Keep in mind, however, that Non-Rigid Alignment is the most time-consuming method and the measurements of the final model may not be 100% faithful to the original.

 

 

Additionally:

Feel free to check this awesome video with a shark, 3D scanned by Artec Gold Partner Qubic:

 

 

 

We are here to help! If you have any questions or issues, please do not hesitate to contact our team by emailing support@artec-group.com or by clicking on "Ask Support" button on the upper part of the screen. We will always be happy to assist you and will get back to you as soon as we can.