3.2 Template Points

THE POINT PROPERTIES DIALOG

POINT CONTRAINTS

EDITING POINTS WITH THE LEFT ACTIVE TEMPLATE WINDOW

NULL POINTS

TESTING POINT CONTROLS 

 

When the template is processed using the corridor modeling command, the points of a template are connected to form breakline features. Each point will be connected longitudinally to the next template drop location to form 3D longitudinal breakline surface features. The breaklines are drawn using the symbology defined with the Feature Definition that is assigned to each point.

Since the template points are connected to generate the completed surface, establishing a standard name for template features that are used on each template is very important to the quality of the proposed design surface. For example, if a Shoulder point is named SHDR_lt on the first template, and it is named Shoulder_Left on the next, the software will not automatically connect these points to generate the breakline feature. Following a point naming convention is important to obtain the best results with Corridor Modeling.

It is equally important to ensure that the feature definition assigned to points is consistent from template to template.

Each template point name must be unique to the template. The software automatically appends a number to the point name if the same name is used during template creation.

There is no limit to the number of points in a template.

 

 

THE POINT PROPERTIES DIALOG

The Point Properties dialog is used to review and edit various properties associated with the template points, including the definition of the point constraints. To access the Point Properties dialog, in the Create Template dialog double-click on the point in the Current Template window. The Point Properties dialog, shown below, is opened.

The dialog contains the following options:

Name displays the point name. The point name can be keyed-in or selected from the drop-down list. If the point name is selected from the list, the corresponding Feature Definition is automatically assigned. Point names must be unique to the template.

Use Feature Name Override displays the name of the feature that will be created in the surface to correspond to the point. This field is optional. If it is blank, then the point name will be used as the feature name.

• The option is intended primarily for end condition components to create connectivity from one station to the next when the template end conditions change. For example, if you want all surface tie-in points to belong to one feature, then set the feature name of all the ending end condition points on each side of the template to the same name (i.e. all Cut and Fill end points on the right would be given the feature name R-Tie and all the ones on the left would be given the feature name L-Tie).
• If the point has a Feature Name Override defined, the point name is displayed in red in the Template window.

Feature Definition is used to define the feature definition of the point. If no style is specified, then it comes from the first component of which the point is a member.

The Superelevation Flag is used to identify the point as a candidate to be used for assigning superelevation control lines. This option should only be toggled on for pavement points on the surface of the pavement.

Alternate Surface allows you to specify the name of an alternate surface for a point. You may choose multiple alternate surface names. Select from the list of available surfaces in the active template.

Member Of indicates in which components the point is included.

Constraints - The Constraints portion of the Point Properties dialog allows you to review/edit the constraints on a point.

• Type specifies the constraint type: None, Horizontal, Vertical, Slope, Vector-Offset, Project to Surface, Project to Design, Horizontal Maximum, Horizontal Minimum, Vertical Maximum, Vertical Minimum, Angle Distance. The constraints are described in more detail below.
• Setting up the appropriate constraint types is critical to achieve the desired results when pavement layers, superelevation, and transitioning are introduced to the design.
• Label displays the optional label for the constraint. Constraints that are labeled can have their value changed during design processing. The same label name can be assigned to more than one constraint and more than one point. See Section 10.4 for details.
• Horizontal Feature Constraint is used to allow a point to target elements in the design file that are defined with the specified Feature Definition within a specific Range. Use of this option is not recommended.

 

POINT CONTRAINTS

Point constraints are used to manage the behavior of points in a template. They are used so that if a point is moved in a template, either by the user editing the template or by the application of a horizontal or vertical control during design processing, all the points related to the point being moved behave in a rational and predictable manner.

For example, when a Simple component is inserted into the active template, it is comprised of four points which are connected to define the component as shown in the example below.

The constraints for all the points in a template can be displayed by choosing the Display Constraints option on the Create Template dialog.

Three of the four points are constrained with relation to the insertion point. If the original insertion point is moved, the other three points move in relation to the first point.

• A point can have at most two constraints. If two constraints are defined, the point is said to be “fully constrained”. A point that is fully constrained is represented by a red plus sign. In the example above, points 2, 3, and 4 are fully constrained.
• A point that is partially constrained, meaning that it has only one constraint on it, is shown as a yellow plus sign.
• An unconstrained point is shown as a green plus sign.

Point constraints are two-dimensional and one-way. Two-dimensional means that the constraints can only affect the points offset and elevation (x and y coordinates in the cross-section view). One-way means there is a child-parent relationship between points. In other words, if point 2 is constrained by point 1, point 1 is said to be the parent of point 2 and moving point 1 will affect point 2, but you cannot move point 2 to affect point 1. The example below shows a sample of this where the blue arrow indicates a parent/child relationship from point 1 to point 2:

  

Constraints are displayed as blue lines between the parent and the child point. At the midpoint of the constraint line, there is a short white line designating the constraint type as follows: 

• Horizontal line = Horizontal Constraint
• Vertical line = Vertical Constraint
• Sloped line = Slope Constraint

Multiple lines will be shown for points with two constraints.

Floating the cursor over a point will temporarily display an arrow designating the direction of the constraint (the arrow points to the child point) and a pop-up menu displaying information about the point.

 

» Point Constraint Types

Horizontal - The child point remains at the given horizontal distance from the parent point. 

• In the example above, point B has been constrained to point A with one constraint as shown below.
• If point A is moved horizontally, point B will maintain its relative distance from point A.
• If point A is moved vertically, point B is unaffected. 

Vertical - The child point remains at the given vertical distance from the parent point.

• In the example above, point B has been constrained to point A with one constraint as shown below.
• If point A is moved horizontally, point B is unaffected.
• If point A is moved vertically, point B will maintain its vertical relationship to point A. 

Slope - The child point will maintain the given slope from the parent point.

• In the example above, point C has been defined with a Horizontal and a Slope constraint as shown below:
• Slope constraints are absolute. Slopes going from lower-left to upper-right are positive regardless of whether the child point is to the left or right of the parent.
• Slope constraints can also have Rollover Values assigned to them. Rollover values are used to set the slope constraint based on variety of high side and low side slope parameters. A Reference Point is specified which defines the controlling slope to the parent point.
• The example above documents the Rollover Values can as defined in CTDOT’s example templates for the shoulder break point behavior. See the online help for more information on the available parameters. 

Horizontal Maximum - The child point has two parent points and remains at the given horizontal distance from the parent point that is farthest to the right (has the maximum horizontal or X value). 

Horizontal Minimum - The child point has two parent points and remains at the given horizontal distance from the parent point that is farthest to the left (has the minimum horizontal or X value). 

Vertical Maximum - The child point has two parent points and remains at the given vertical distance from the parent point that is highest (has the maximum vertical or Y value). 

Vertical Minimum - The child point has two parent points and remains at the given vertical distance from the parent point that is lowest (has the minimum vertical or Y value). 

Vector Offset - The child point has two parent points and will be projected onto the vector defined by the two parents. If the offset is not zero, then the child point will maintain a perpendicular

offset from the parent vector at the specified offset value. Negative values indicate an offset to the left of the vector defined by the parent points. Positive values indicate an offset to the right. 

Project to Surface - This constraint must be used in conjunction with one of the previously define constraints. The other constraint will define the projection direction. The child point will then be projected to the surface with the name or parametric label given when the design is processed. If the surface does not exist, or no solution is found, then the point will remain where it is placed in the template. 

Project to Design - This constraint is like the Project to Surface, except that the point is projected to the design surface of the template. A projection value is given to indicate whether the projection is to be to the left or to the right. The point must also be constrained by one of the previous constraints, excluding the Project to Surface, so that a direction for the projection may be determined. A negative value limits the projection to the left of 0; a positive value limits the projection to the right. A value of 0 will seek to the left and to the right of 0 to project the point. If no solution is found, then the point will remain where it is placed in the template. 

Angle Distance - This constraint takes two parent points, a distance, and an angle. The selected point is then fully constrained to the location defined by the first parent, and the angle from the first parent relative to the vector defined by the two parent points. This constraint creates a rigid-body rotation. When selected, no other constraint types are available.

 

EDITING POINTS WITH THE LEFT ACTIVE TEMPLATE WINDOW

In addition to the Point Properties dialog, points can be edited from a pop-up menu that is accessed by right-clicking on a point in the Active Template window. The menu is shown below.

 

NULL POINTS

A null point is a template point that is purposely not related to any particular component. It’s most often used as a reference for controlling other points. To create a null point, right-click in the current template window and select Add New Component > Null Point, or select Add > Null Point from the pull-down menu of the Create Template dialog to initiate the command.

 

TESTING POINT CONTROLS 

The behavior of fully constrained points can be tested by right-clicking on the point and selecting Test Point Controls as shown below. Select the desired option to test the behavior of a template as the point is moved either horizontally, vertically, or both at the same time.