Creating a Surface Profile Analysis

Critical curve speed formula, where  ‘e’  is %  elevation:

Fall formula, where  ‘e’  is angle of takeoff:

Vault speed formula, where  ‘e’  is angle of takeoff in degrees:

Slide to stop speed w/Time formula, where  ‘e’  is %  grade:

Inasmuch as generally, these facts are included in both the above formulas and final report narrative, they can be easily determined.

If the skid marks were documented using several ‘shots’ along the length of the mark, simply click on the various segments of the line (skid mark) and make a note of the grade calculated and displayed in the ‘properties’ dialog box, as seen here:

And then, by averaging the segment’s percentage, the grade is determined.  If we wish to further illustrate this scene and grade in a 3D form, possibly even using the benefits of an animation … these steps follow.

First, let’s address how we want the scene to appear.  Notice here the scene appears to resemble an ‘asphalt’-appearing surface. 

If we, at any time, left click, then right click on the scene we get this dialog box.  First make sure the “Fill Style” is set to ‘Texture’.  Then, under ‘Texture’ select from the choices available.  Note that ‘Water’ is available too for use in a marine application or to indicate a ‘standing water’ area on a roadway.

You will notice next, I’ve changed the road surface ‘texture’ for ease of viewing (from ‘asphalt’ to ‘new asphalt’) and have added a full side sedan and changed its color to white.

When we initially transfer this into 3D, the below is seen (Jul05).  Notice that the vehicle shape isn’t set to the road surface’s correct % of grade. 

A situation that can be overcome by clicking on the vehicle, then changing the ‘properties’ of the vehicle to reflect the skid marks initial & ending road elevation (and any others along its eventual CM path) … as seen below.

 (a work under construction … )

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