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How does Crash Magic determine what collision symbols to display

Article created: Apr 12 2011, updated: May 18 2011

Background:  This article is to help users determine how Crash Magic has calculated the collision symbols to render based on the collision records

Status:  Info - "how to" article
Keywords:  diagram,missing,symbols
Categories:   *Configuration* *Diagrams* *Article - references*


Crash Magic displays collision symbols based on the rules for each configuration. These rules are held in the .shared user of group. Specifically the object map of the .shared user maps collision graphics to the crash records. The object map contains expressions that determine what symbols to display. This article covers how group administrator can view the rules for display of collision symbols.

This article does not cover changes to the configuration. Users should contact Pd' Programming if they require changes to their configuration.

This article also does not cover the placement of collision graphics.


When a diagram is created Crash Magic will iterate through all of the collisions provided by the study. Each collision record is compared with the list of  graphic objects in the object map. Each graphic contains a condition that determines if a graphic should be displayed. Each crash record is compared against the graphic object conditions to determine if they should be displayed.

Changing an object map is an advanced subject, and should not be done without understanding all of the implications. This article is only for the purpose viewing collision placement logic.

The following are steps to view the object map:

  1. Log into Crash Magic as a group admin
  2. Click on the + sign next to the .shared in the admin tree on the left under the user group that you have logged into
  3. Click on the + sign next to the object map
  4. Click on the Default under object map
  5. Click on the green settings tab

The settings tab will contain a list of graphics to be displayed in the list box on the left. By selecting an item in the list, the expression box will show the rule for display of the graphic. The Symbol box will show the symbol selected.

The Expression box contains a condition under which the selected graphic is rendered. The Expression must resolve to true or false. If the expression resolves to true the graphic is displayed. If the expression resolves to false the graphic will not be displayed. Expressions use the crash record fields from the collision database, and calculated fields that are derived from the collision database.

The Symbol box shows the symbol to be displayed and can also contain an expression. The expression can determine the exact symbol to show based on other conditions. For example the symbol box could contain an expression to show a bike if a bike resolved to true or an auto if resolved to false.

October 23, 2019 4:46AM

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