Bullet Trajectories

Discuss all Clouds2Max related issues here.
Post Reply
User avatar
ddustin
V.I.P Member
V.I.P Member
Posts: 918
Joined: Mon Aug 22, 2011 9:28 pm
Full Name: David Dustin
Company Details: FARO Technologies
Company Position Title: Dir of Public Safety Forensic Services
Country: USA
Linkedin Profile: Yes
Location: Georgia, USA.. Planet Earth
Contact:

Bullet Trajectories

Post by ddustin » Sat Jun 29, 2013 9:36 pm

Eugene Liscio, my son Jesse and I attended a Shooting Incident Reconstruction class this last week in Omaha, NE.
Here is an image from a scan we took and how we created trajectories from the scan.
David
Image
Forensic Animation, 3D visualization

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1357
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Contact:

Re: Bullet Trajectories

Post by jcoco3 » Sat Jun 29, 2013 9:50 pm

Very cool, You guys have all the fun! Who had the pleasure of gunning down the old clunker?
It looks like some bullets hit the front glass. Is it possible to establish a bullet trajectory when the bullet goes through safety glass?

User avatar
ddustin
V.I.P Member
V.I.P Member
Posts: 918
Joined: Mon Aug 22, 2011 9:28 pm
Full Name: David Dustin
Company Details: FARO Technologies
Company Position Title: Dir of Public Safety Forensic Services
Country: USA
Linkedin Profile: Yes
Location: Georgia, USA.. Planet Earth
Contact:

Re: Bullet Trajectories

Post by ddustin » Sat Jun 29, 2013 9:54 pm

A former FBI Agent did the perforation.
As far as determining trajectory through glass, it is certainly possible but you need a reliable point of termination (essentially 2 points).
David
Forensic Animation, 3D visualization

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1357
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Contact:

Re: Bullet Trajectories

Post by jcoco3 » Sat Jun 29, 2013 10:00 pm

:lol: "perforation"

Two points makes sense. Learn something everyday.

User avatar
ddustin
V.I.P Member
V.I.P Member
Posts: 918
Joined: Mon Aug 22, 2011 9:28 pm
Full Name: David Dustin
Company Details: FARO Technologies
Company Position Title: Dir of Public Safety Forensic Services
Country: USA
Linkedin Profile: Yes
Location: Georgia, USA.. Planet Earth
Contact:

Re: Bullet Trajectories

Post by ddustin » Sat Jun 29, 2013 10:04 pm

jcoco3 wrote::lol: "perforation"

Two points makes sense. Learn something everyday.
Actually, I wasn't trying to be funny (for a change). Perforation is correct when describing the nature of the hole.

David
Forensic Animation, 3D visualization

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1357
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Contact:

Re: Bullet Trajectories

Post by jcoco3 » Sat Jun 29, 2013 11:29 pm

I learned two things today :D Its been a good day!
...I still think that word is an amusing way to describe a bullet hole, but in all seriousness I really need to attend one of your presentations. I know so little about the forensics industry :( I assume you or Eugene will be presenting at the Faro conference?

Not trying to detract from the topic here, so I have a couple more questions to get back on track. I have noticed from other post here that wood dowels with spherical targets on the same axis passing through the "perforations" seem to be a good way to establish trajectory, but I assume that they require either two points of perforation or 1 long cylindrical perforation to establish a good trajectory. Is there anyway to establish trajectory from a single impact location like a concrete wall or steel plate that the bullet did not penetrate completely? Sorry if this is something previously covered, but it seems like it might be possible after scanning the impact site in high resolution and comparing the scans to some test scans where the origin of the bullet was known.

User avatar
3DForensics
Global Moderator
Global Moderator
Posts: 1743
Joined: Mon Aug 03, 2009 1:52 am
Full Name: Eugene Liscio
Company Details: AI2-3D Forensics
Company Position Title: Owner
Skype Name: eliscio
Location: Toronto, Canada
Contact:

Re: Bullet Trajectories

Post by 3DForensics » Sun Jun 30, 2013 9:37 pm

Depending on the material you can often make an estimate of the direction from which the bullet impacted a location based on the shape of the hole. A circular impact is at 90° to the surface and as it becomes more oblique, the hole turns to an ellipse. You can use the equation:

sin (Θ) = width/length

theta is the angle of impact
width is the minor axis of the ellipse
length is the major axis of the ellipse

This is an estimate though and usually, the more elliptical the shape, the more accurate the result. Angles close to 90° are difficult to estimate since they are very close to circular and a small change in the width to length ratio has a big change in the impact angle.

This is the same premise as bloodstain pattern analysis. This is video that I made some time ago showing the projection of a blood drop on a tiled floor. It is the same for a stable bullet in flight.

[youtube]http://www.youtube.com/watch?v=M1TzSkrS2YM[/youtube]

Cheers,

Eugene

Post Reply

Return to “Clouds2Max”