Author Topic: When is it Best To Draw Scenes in 3D?  (Read 21300 times)

Bob Galvin

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When is it Best To Draw Scenes in 3D?
« on: May 10, 2012, 08:47:28 AM »
WHEN IS IT BEST TO DRAW SCENES IN 3D? NEARLY ALWAYS, SAYS ONE CANADIAN INVESTIGATOR

When it comes to diagramming crime scenes, the decision as to whether to create the scene in 2D or 3D seems to be a matter of choice. Many prefer doing most scenes in 2D. Yet, if the scene is complex, and particularly if it involves a shooting crime, a 3D representation probably will be clearer to a jury. That’s the opinion of Sgt. Tim Kravjanski of the West Vancouver P.D., British Columbia. The sergeant, who is a member of Vancouver PD's collision analysis team, investigates both crash and crime scenes. And he has been a user of the Evidence Recorder and MapScenes Forensic CAD software programs for years; he began using the software when its second version premiered.

3D Diagram Revealed Shooting Scene’s Details, Witness Perspectives

It is clear to see why Sgt. Kravjanski prefers building his scene diagrams in 3D.  For example, he recalls an incident in which two males were shot on a roadway near an elevated apartment complex with a parkade. Witnesses, the sergeant explains, were standing on the deck above the parkade and watched the shooting incident unfold. “For evidentiary purposes, we created a 3D diagram of the whole area in MapScenes, including the apartment with its decks,” Sgt. Kravjanski said. “This allowed distances to be measured, and to show where witnesses were positioned and what they saw, and any obstructions in the way,” Sgt. Kravjanski said. “The 3D diagram was perfect because you could also see where trees were and how tall they are.”

EvR Labels Points, Produces Linework, Displays in Real Time

Before he can create  his 3D diagrams in MapScenes Forensic CAD, Sgt. Kravjanski captures scene evidence with a total station that is linked to the Evidence Recorder software program. The EvR has proven to be a valuable tool for instantly capturing and displaying scene evidence. Describing the software’s attributes, Sgt. Kravjanski specifically noted, “With EvR, it’s the ability to put a note on every point that you take and do it quickly instead of having to try and do it right at your total station.” And, although the data collector in the total station has a keyboard on it, the sergeant uses a touch-screen version which allows display of the mapping diagram. In this way, he said, “I can actually see the diagram being drawn out right on the data collector so that I know if I’ve missed a point or misplaced a point right away. I can see this immediately.”

What’s more, EvR not only displays the diagram, but fills it with important details such as linework and labels, all in 3D and with proper polar coordinates. “Once I take the diagram into MapScenes, the only thing I would do is to add trees, signage, telephone poles and any other details,”Sgt. Kravjanski said. “It depends on how complex I want to go.”

Mapping in 3D Makes Diagramming Scene Easier

There is no question that 3D gives a diagram the most complete perspective of a crime scene’s likely events. But does every scene truly warrant 3D depiction, especially since it takes longer to create? “I find if I’m meticulous at the scene, if I take the right points, this simplifies my work back at the office (building the diagram),” Sgt. Kravjanski said. “If I take enough 3D texturing points in the field and envision it in my mind while I’m there, I can create the diagram quite quickly. This is because there are already 3D elevation points that are labeled in EvR,” the sergeant continued. “I link those and put textured surfaces on them.”

Sgt. Kravjanski also uses EvR’s capability to rotate throughout a mapped scene in 3D. If he plans to use the scene in Forensic CAD, he will rotate around the scene while he has it in EvR. “I do this so I can make sure my points are correct,” the sergeant said.

Satellite Maps Used to Overlay Crime Scene Drawing

Some scenes are complex enough to warrant the use of satellite maps to assist in mapping scene evidence. Sgt. Kravjanski recalls a homicide incident in a park that covered about 1,000 acres. In the middle of the park, far away from any reference point, he and his investigative team had to locate approximately where the crime occurred. This required moving the transit seven times to be able to shoot the entire scene and then reference back to the parking lot. “Based on that, and since we produce fly-over maps every two years, we were able to put our survey data (of the park  homicide scene) from MapScenes on top of the map so that we would have the crime scene overlaid onto a photograph of the area,” Sgt. Kravjanski said.

Data is Secure as All Changes Logged

As for MapScenes Forensic CAD itself, Sgt. Kravjanski says it is straightforward, highly accurate, and a true CAD drawing program. It is also easy to add details or change them. However, the integrity of all data is always high since it is secure. “Every change you make is logged,” Sgt. Kravjanski emphasizes. “For court purposes, there’s a log in the software of what you’ve done. If  you delete a point, it’s logged. And you have to have a good reason for deleting that point,” the sergeant added.

MapScenes Used For Olympic Challenge

Sgt. Kravjanski and his team are called upon to investigate a wide variety of scenes, including large scenes, apartments, parks, streets, and police involved shootings “where we’ve had to map an entire neighborhood.” But an even bigger challenge occurred during the 2010 Winter Olympics hosted by Canada and taking place throughout Vancouver, B.C. The West Vancouver Police Department plus many other law enforcement agencies needed to identify some of the area where special events would be held. “Accurate maps did not exist,” recalls Sgt. Kravjanski, “so we mapped those areas with a total station and imported the data into MapScenes. We had these maps ready for use at any time.” Although the Olympics have come and gone, these venues are still in use today. Luckily, since they were all documented in MapScenes, diagrams of these venues also are still being used as well.
« Last Edit: May 22, 2012, 08:35:11 AM by MapScenes Admin »

poizvi

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Re: When is it Best To Draw Scenes in 3D?
« Reply #1 on: June 04, 2012, 10:21:35 PM »
I would go for 2d in the cases which are most complicated. Also more cost effective.