Conservation of Momentum

From your evidence evaluation, position vehicles at POI (example shown):

Press the [M]omentum button at screen top toolbar:

Pick ‘Close’ on the “Momentum Analysis Wizard” for right now:

Note the C.M. ‘grip’-based X,Y component.  Notice the number of ‘grips’ to be dealt with for both vehicles.  Zoom in and place the center ‘grip’ where you believe the centroid of the crash to be:

Move next ‘grips’ to each vehicles CM:

Extend the end ‘grips’ out for each vehicle, in direction of approach to POI (length does not matter, however direction does):

From physical evidence, extend other end ‘grips’ to point of rest positions for both vehicles:

From physical evidence, extend center ‘grips’ along CM path to point of rest positions.  The ‘grips’ can be moved along the CM line to conform to physical evidence marks or prints.

Once satisfied that the shapes represent the POI and CM of each vehicle, and that the approach(pre-impact), post-impact and final rest positions are certain … VistaFX is now ready to do the C of M analysis.

Press again the [M]omentum button at screen top:

The below dialog box appears, read the information and press NEXT:

Fill in the necessary information, Press NEXT:

Review, then press NEXT unless you have done a Crush analysis preceding this Step:

Review, then press NEXT.  This dialog lists angles as determined from where you placed certain ‘grip’ points from physical evidence:

Fill in the vehicle attributes here, or Select Exact Vehicle data, then press NEXT:

Review and indicate  f  for each vehicle, then press NEXT:

Results from your crash reconstruction inputs now will appear.  One can use the ‘grips’ to secondarily modify CM path if, or as necessary, and the I speed summary results will recalculate automatically.

If, as in this sample scene scenario, we’ll accept the results while conform to within ‘acceptable limits of accuracy’ based on hand calculations completed elsewhere.

We will now move toward creating a 2D and 3D animation of this collision.

Turn the ‘momentum’ layer off (from screen top toolbar), then press CLOSE:

Left, then Right-click on either vehicle (blue vehicle shown here):

Pick next on ‘Copy Path from Momentum Vehicle 1” …

After doing same for both individual vehicles, Left click on a vehicles’ pathway (blue vehicle shown here):

Right click and choose Path Properties:

Click center of dialog to open 3D viewer screen:

Notice first, that Segment 2 of the movement of the blue vehicle has been selected.  Notice as well, the time (sec.) and indicated distance for this segment.  These are variables which you selected when positioning earlier the CofM pathways with ‘grips’.  Note as well, the 360-deg. freedom of movement for viewing this segment of the crash.

Select Segment 3, Post-Impact Path to view final segment.

… to be continued … 

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