Sight Distance

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Ribbon: Model Viewer > Analysis Tab > Sight Distance

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Introduction

Model Viewer contains some very impressive tools to calculate sight distances along a road and at intersections to ensure minimum design standards are met. Users can create their own sight criteria styles where parameters such as eye height, target height, and minimum sight distance lengths are specified. A grade correction table can also be setup to adjust the minimum sight distance based on the vertical grades along the road.
Visible and obstructed sight lines are displayed in Model Viewer and can be exported out as polylines into CAD.

When design changes are made to a road, the sight distance tools will update automatically when the auto update option is turned on. This allows the designer to check the suitability of a design as soon as vertical or horizontal changes are made to the road.
 

Ribbon Tab and Navigation

This command forms part of the following tab:

Information on navigation in the Model Viewer 3D environment is available when reviewing the Model Viewer command help.

Details

Once the Sight Distance command is selected, a separate tab on the ribbon is displayed, with command inputs as follows:

Road	Pick list of roads in the project to display sight lines for.  A message will display if no sight distance controls have been applied using the Setup Table form
Show Visible Lines	Toggle on/off the display of visible sight lines
Show Obstructed Lines	Toggle on/off the display of obstructed sight lines
Reverse Direction	Reverse the direction of the sight distance analysis
Intersection Check	Applies sight distance lines for the intersection. The user will be required to setup an intersection check using the Intersection Check command (see below).
Setup Table	This command allows users to setup a sight distance check for a specified road. The user can specify different sight criteria styles at certain locations along the road. A form will display with inputs as follows:   Road Name Select the road to create a new sight distance table for Check Interval Specify the check interval. The software will compute sight lines at each chainage. Users can specify a different sight criteria style at each chainage. Start Chainage Specify the start chainage for the analysis range End Chainage Specify the end chainage for the analysis range Sight Criteria Specify the initial sight critera style for when the Setup button is used. Setup The sight distance table is populated with the sight criteria style assigned to the road at the interval specified. Sight Distance Lists chainages and the applied sight distance Criteria at each chainage   Chainage The location of sight line   Sight Criteria The sight criteria style the sight line will utilise for calculation   Edit Allows the user to edit or create a new sight criteria style   Description Allows the user to type in some extra information in regards to the sight line check. This description can also be displayed on the table output.   Add Chainage Allows the user to add an additional sight line at the specified chainage   Override Selected The user can select multiple sight lines from the list and override their sight criteria style with the sight criteria style specified. OK Saves the current setup table and exits the dialog. The software will update the sight distance calculations. Close Exit the form
Intersection Check	This command analyses sight distance at an intersection.  A form will display with inputs as follows:   Main Road     Alignment Select the main road alignment from the list   Intersection Specify the chainage on the main road where the side road intersects the side road. Once the user selects the side road alignment, the software will calculate this chainage and update this field.   Check Interval Specify the check interval. The software will compute sight lines are the interval specified.   Use ISD from Criteria Style Select whether the software uses the minimum sight distance length from the sight criteria style specified, or by using the distance to point b and point c along the main road. Users can specify the chainage for point b and point c if this option is ticked off. Side Road (Point A)     Alignment Select the side road alignment from the list. The intersection chainage field should update when a new side road is selected.   Chainage Select the chainage along the side road representing the start location of the intersection check. Start Target (Point B)     Chainage Describe what each option does and how the controls work. Note: this field will be disabled if Use ISD from Criteria Style is ticked on Use the 'pick' icon to select the intersection location from the drawing.   Criteria Style Select the sight criteria style used when computing sight lines in the direction of point b. End Target (Point C)     Chainage Describe what each option does and how the controls work. Note: this field will be disabled if Use ISD from Criteria Style is ticked on Use the 'pick' icon to select the intersection location from the drawing.   Criteria Style Select the sight criteria style used when computing sight lines in the direction of point c. Graphic View The graphic at the bottom of the form visually describes each of the user inputs and updates as the mouse hover passes over each input field OK Apply and exit. Close Exit the form without saving.
Sight Criteria	Establishes how the sight distance should be applied, as well as setting colours for visible and obstructed lines.  A form will display with inputs as follows:   Criteria Name A list of all available sight criteria styles are listed, Users can create a new criteria style by pressing . Criteria styles can be deleted by pressing Design Speed Specify the design speed (this value will have no affect on calculations) Type Specify the sight distance check type (this value will have no affect on calculations) Minimum Sight Distance Specify the minimum sight distance used when this sight criteria style is assigned to a sight line Grade Correction Click here to open a new form to apply grade corrections based on the longitudinal slope of the road. The software will intelligently read the vertical profile of the road and apply the sight distance length adjustments as specified. Inputs are as follows:   Use Grade Correction Table Adds the values to the Minimum Sight Distance, based on the Grade input and the Correction value. Upgrade Establish changes to the Minimum Sight Distance based on uphill grade   Grade 1- 4 Type in grades (%)   Correction Type in a distance to add to the Minimum Sight Distance value.  Positive to increase and negative to decrease. Downgrade Establish changes to the Minimum Sight Distance based on downhill grade   Grade 1- 4 Type in grades (%).  Use negative values for the downhill grades   Correction Type in a distance to add to the Minimum Sight Distance value. Positive to increase and negative to decrease. Apply Apply and exit. Eye Height Specify the eye height (start location for the sight line) Eye Offset Specify the eye offset (start location for the sight line) Target Height Specify the target height (end location for the sight line) Target Offset Specify the target offset (end location for the sight line) Visible Sight Lines Set display for visible sight lines   Colour Click on the colour swatch to open a colour selection form.  Click OK to select the new colour.   Lineweight Type in an integer for the lineweight to apply. Obstructed Sight Lines Set display for obstructed sight lines   Colour Click on the colour swatch to open a colour selection form.  Click OK to select the new colour.   Lineweight Type in an integer for the lineweight to apply. OK Apply and exit. Cancel Exit the form without saving
Report	Users have the option to display the results of the sight distance check in a table format. This table will update dynamically as the sight distance command is computed. All information regarding the sight lines used as part of the compuation are listed, Users can filter the list by specifying a chainage range and the display of visible and obstructed sight lines can be toggled on/off. The report can be outputted to a table in CAD or a CSV file. Once selected, the following form will display Chainage Establish report extents and compliance to display   Start Start chainage/station to commence report   End End chainage/station to finish report   Show Visible Toggle on/off the display of the visible sight lines   Show Obstructed Toggle on/off the display of the obstructed sight lines   Report Settings This will open up the Report Settings to enable configuration of the report output.  Inputs as follows: Table Title The title of the outputted table - used when outputted to a CAD table Table Style Specify the AutoCAD or BricsCAD Table Style Table Font Specify the font of the outputted CAD table Item List Spreadsheet view listing available items to report.  Tick items on/off to include in the report.  Width is used for any Table outputs to the drawing   Visible Toggle on/off the display of the item in the report   Name The name of the item (this cannot be edited by the user)   Display Name Specify the display name. This value is used when the report is outputted to a CAD table or CSV   Decimal Places Specify the decimal places of the value   Width Specify the column width for this item in the CAD table Save Settings Apply and exit. Close Exit the form without saving.   Table Output Output the report to a CAD table (either AutoCAD or BricsCAD table)   File Output Output the file to a CSV file. The file will automaticallty load (in the default program for the file type) once saved.
	Close the sight distance tab. Once this tab is closed, the sight distance check will no longer automatically update when Model Viewer is refreshed.