msmac3D Now Uses Vehicle Shape, Not Rectangles

[MSI]

Some SMAC users have encountered issues with the original SMAC definition of rectangular vehicles.
Particularly In low speed impacts.

• While SMAC has decades of proven validation and correlation with real world crashes using the rectangular definition of the vehicle,
• The timing of initial contact can be an issue to explain (forces before the rounded corners touch!).

In response

• McHenry Software has modified msmac3D (on option choice) use the actual vehicle shape of each vehicle for contact detection.

The updates will be delivered to all msmac3D licenses shortly with many additional enhancements, etc.
stay tuned!


With a rectangle representation, the vehicles detect contact at 0.024 seconds early and the DeltaVs are only slightly changed:

deltaV comparison.png (20.87 KiB) Viewed 19664 times

figure below: comparison of old vs polygon definition, note the magenta rectangle is for comparison

rectangle v vehicle shape.png (630.25 KiB) Viewed 19664 times

[MSI]

Here's a better video display of the new msmac3D shapes
NOTE: the below graphics have a dashed white line vehicle outline display which is optional and for illustration purposes only

[MSI]

HOWTO Video with links to specific tasks now uploaded here:

• HOWTO use the Polygon Shape for Collision Interaction

Also repeated below:

• Right click on Mouse on link
  select Open in new Tab or Window to keep this list open and available
  OR simply click on link and use back button to return to this list

  Time on Video	Link to place in Video on Topic
  @0:22	Howto Open Charts
  @0:38	Run 2D animation with collision reference vectors
  @1:47	Vehicle Select Menu Option
  @2:21	HOWTO Turn ON Polygon vehicle definition for collision interaction
  @2:27	HOWTO Display Polygon Boundary
  @2:58	Comparison accelerations chart rectangle vs polygon
  @3:25	HOTO Show the polygon exterior of vehicle in 2D graphics
  @4:14	Comparions 2D graphics using Rectangle vs Polygon
  @4:50	Turn OFF Polygon vehicle definition

[MSI]

July 29, 2021: Update to Polygon
Couple changes to the option to use the polygon periphery for the collision partners.

• We added veh3 to also have a polygon periphery
• We added the option to turn off the polygon periphery definition
  • set field 9 of input card 13 to < 1 (for veh1/Veh2 collision interaction)

    

    Turn off Polygon.jpg (8.6 KiB) Viewed 19409 times

    and field 9 of input card 98 to < 1(for veh2/Veh3 collision interaction)

    

    Turn off PolygonV3V2.jpg (7.34 KiB) Viewed 19409 times

• To check/display the actual polyline used
  • In 3D graphics to turn on a display of the polygone defintion, select the Veh menu:

    

    Us Poly Menu with display.jpg (19.13 KiB) Viewed 19409 times

    For 2D graphics we have added a Poly button which displays the polygons for each vehicle

    

    Poly display 2D.jpg (47.16 KiB) Viewed 19399 times

    (not using the LoadOb Veh1, 2 or 3 you can individually load these files too)
    When you choose the polygon option 2 or 3 files are created in the project directory
    • vehicle01poly.veh
    • vehicle02poly.veh
    • vehicle03poly.veh

NOTE:

• If you are using the 2D graphics and use the POLY button AND are using an SA5 input file (you don't need an SA5 file)
  The Poly button load (or load VEH/SCE objects interactively) will reset at the cycle/end of run/restart of display at 0.0
  • to avoid the reset for polygons/etc
    include these lines in the sa5 input file (and again you do not need to use an SA5 file)
    You can by including this in the inputs:
    
    • include=vehicle01poly.veh
      include=vehicle02poly.veh
      include=vehicle03poly.veh
      
    before the lines in your sa5 file:
    • OPTION=END
      3.

For additional information see Help->smac2D graphics or online here SmacGraphics2D manual section on include command