3D Printing for Forensics

[3DForensics]

I thought I would kick this section off with a short post and a couple of examples.

I worked on a case a while back that was a homicide (stabbing) and the victim was found a long time after being killed so there wasn't much left except for bones. One important finding noticed during the examination was that there was a particular vertebrae that had markings on it from a sharp weapon.

We had the vertebrae scanned and this was important for use in a reconstruction of the stabbing. Since we had the 3D model of the vertebrae it was also decided to create a 3D print at a later date. The print is really quite something and speaks volumes about how a complex object can be easily created using these methods.

VertScan.jpg

vertebrae1.jpg

Another use of 3D Printing that is not so common is with fingerprints. If you can scan a suspect's finger...

fingerprint.jpg

Looking forward to seeing other examples of 3D Printing!

Cheers,

Eugene

[3DForensics]

For those who might be interested, I wrote up a short article a little while back in Forensic Magazine.

Forensic Uses of 3D Printing

Eugene

[colhum1]

Very interesting article Eugene, thanks for sharing.

[tbwester]

Thanks for sharing, nice examples.

[Jason Warren]

Eugene, that's great, thank you.

Sorry to diversify from forensics, but from your experience, what would be the best way to get a detailed 3D point cloud of the gates shown below to a 1/20 scale model 3D print?

G1.jpg

[3DForensics]

Hey Jason,

When you say "the gates" are you talking about just the metal gate or the structure around it inclusive?

I would consider photogrammetry or a hand held scanner for the highest level of detail. The nice part is that most of these systems either automatically convert the cloud to a mesh so you don't have to worry about meshing in another package.

Of course, you could just try a regular terrestrial scanner up close and with a bit of clean up you should be good to go.

Eugene

[Jason Warren]

Hello Eugene,

Sorry more questions ;o)

I`m looking at the metal gates and the supporting stone archway. I`m thinking of scanning with my trusty Leica HDS4500, and then sending to the 3D printers a clean, registered point cloud. Presumably they will be able to create a detailed mesh and then print to the desired output?

[3DForensics]

I would expect that anyone doing 3D printing will have different software for meshing, filling holes and sculpting. Of course, they may very well charge a fee for their time to do this, but if you don't have the patience or $$ to buy some of the more expensive meshing software, then that would be the most practical way to go.

Cheers,

Eugene

[tbwester]

Jason,
I don't have a ton experience printing, so take my advice with a grain of salt.

I would scan the gate, trace it in 2D. Then extrude the 2d to a given thickness for printing. Or you could mesh it. A mesh might be faster -but it just depends on how much time it takes to clean the mesh.

One issue that I can see is that if the gate is only 15cm wide and you reduce the size by 1/20, the printer might not like printing out something that thin. Also, with how the gate is built - you risk the print collapsing during the printing process.

On the printing I have done, I have consulted with a local print shop - and that has saved me a lot of mistakes. They can tell right away what prints well and what will be a problem. Kind of like how we know what will scan easily and what will be a pain!

[Jason Warren]

Thanks for your comments...much appreciated