In Civil 3D, when you type CCALC in the command line, it actually opens the Curve Calculator dialog.

What is the Curve Calculator?

The Curve Calculator in Civil 3D is used for solving circular curve geometry, often used in alignments, road designs, and parcel layouts. It helps calculate unknown curve parameters based on given values.

What Can You Do with the Curve Calculator?

You can enter different curve parameters, and the tool will compute missing values. The standard curve elements include:

• Radius (R) – The distance from the center to the curve.
• Arc Length (L) – The curved distance between two points on the arc.
• Chord Length (C) – The straight-line distance between the start and end of the curve.
• Delta (Δ) – The central angle of the curve.
• Tangent Length (T) – The distance from the curve’s start point to the point of intersection of the tangents.

How to Use the Curve Calculator (CCALC)?

1. Type CCALC in the command line and press Enter.
2. The Curve Calculator dialog box appears.
3. Input known values (e.g., radius and arc length).
4. Click Calculate to compute the missing values.
5. Apply the results in your alignment or design work.

Why Use CCALC?

✅ Helps ensure accurate curve calculations for roads and railways.
✅ Saves time by solving complex curve formulas automatically.
✅ Ensures consistency in geometric designs.