Creating a Design Profile with Tangent to Tangent Width Curves Method

In this comprehensive tutorial, we'll create a sophisticated design profile for branch alignment using the tangent-to-tangent width curves creation method—a fundamental technique for professional civil engineering design. Navigate to the profile dropdown menu, select "Profile Creation Tools," then choose your designated view window. For this demonstration, we'll maintain the default naming convention while selecting our alignment dev branch, specifying a design profile with a complete label set for professional documentation standards.

Click OK to proceed. If you encounter unresponsive interface buttons—a common issue in complex CAD environments—save your work, close the application, and reopen it before continuing. This ensures optimal software performance and prevents potential data loss during critical design phases.

Now we'll leverage the "Draw Tangents with Curves" option, which provides superior control over profile geometry. However, before beginning the design process, we must configure our curve settings—a critical step that determines the quality and compliance of your final design. Within the curve settings dialog, you'll find three primary curve types: parabolic, circular, and asymmetric curves, each serving specific engineering applications.

Professional best practice dictates using parabolic curves for most roadway applications due to their superior driving dynamics and compliance with modern design standards. The interface presents options for both crest curves (convex vertical curves at hilltops) and sag curves (concave vertical curves in valleys), allowing you to specify either length parameters or K-values as your design foundation. Length-based design offers more intuitive control, with 150-unit defaults providing a solid starting point for most applications.

Before proceeding with the tangent-to-curves creation method, take a moment to understand the comprehensive toolset available in the Profile Layout Tools toolbar—these tools form the backbone of professional profile design. The toolbar includes PVI (Point of Vertical Intersection) creation and deletion tools, essential for managing vertical alignment control points. When you have excessive tangent sections or need to eliminate unnecessary intersections, the PVI deletion tool streamlines your design by removing unwanted elements.

The PVI movement functionality offers both toolbar-based and grip-edit methods, providing flexibility in your design workflow. Additional tools include single-line drawing capabilities for simplified geometry, dedicated curve drawing tools for complex vertical alignments, and orientation/conversion utilities for integrating existing AutoCAD lines and splines into your profile design.

Advanced features include tabular PVI insertion for precise coordinate-based design, raise/lower tools for bulk elevation adjustments, and profile data copying for standardizing designs across multiple alignments. The build method selection—PVI-based versus entity-based—determines how the software interprets your design intent, with PVI-based typically offering more predictable results for conventional roadway design.

With our curve settings configured, select "Draw Tangents with Curves" and focus on the profile view window. Begin by zooming to an appropriate scale and snapping precisely to the endpoint of the existing terrain profile—accuracy at this stage prevents downstream design complications.

As you develop your design profile, observe the terrain's natural characteristics: the upward curve transitioning to a downward slope, then rising again. Professional profile design involves creating a balanced alignment that minimizes earthwork while maintaining safe driving conditions. Position your first point above the terrain crest, accounting for adequate clearance and sight distance requirements. Continue to the sag area, ensuring proper drainage characteristics, then snap to the terminal endpoint.

Upon completion, your profile will display three distinct tangent sections connected by two vertical curves—a crest curve and a sag curve. This configuration represents a typical roadway profile that balances engineering requirements with natural terrain characteristics. Close the Profile Layout Tools to complete this phase of the design process.

Save your work before proceeding—maintaining regular backups is essential in professional design environments where data integrity directly impacts project success. In our next session, we'll explore grid editing methods for precise profile refinement, enabling you to optimize your design to meet exact project specifications and regulatory requirements.