Overview The Arc primitive represents a segment of a circle in 3D space. It is defined by a center point, radius, start angle, end angle, and the number of segments used for tessellation. When the angle range equals 2π, the arc forms a complete circle.
Use Cases:
Creating circular arcs and curves
Drawing complete circles
Rounded corners and fillets
Circular patterns and designs
Constructor let arc = OGArc :: new ( "arc-1" . to_string ());
const arc = new Arc ( options ?: IArcOptions );
Rust Constructor Parameters Unique identifier for the arc instance
TypeScript Constructor Parameters Configuration options for the arc
Optional unique identifier (auto-generated if not provided)
Starting angle in radians
Number of line segments to approximate the arc (higher = smoother)
Arc color as a hexadecimal number (e.g., 0x00ff00 for green)
Enable thick line rendering using Line2
Line width when fatLines is enabled
Methods set_config arc . set_config ( center : Vector3 , radius : f64 , start_angle : f64 , end_angle : f64 , segments : u32 );
Updates the arc’s geometric parameters. arc . setConfig ( options : IArcOptions );
Updates the arc configuration and regenerates geometry. generate_geometry // Called automatically by setConfig
Generates vertices along the arc using the specified number of segments. For closed arcs (full circles), it automatically creates a face.
get_geometry_serialized let geometry : String = arc . get_geometry_serialized ();
// Used internally for rendering
Returns serialized vertex buffer data as a JSON string.
get_brep_serialized let brep : String = arc . get_brep_serialized ();
const brep = arc . getBrep ();
Returns the complete BREP representation including vertices, edges, and faces.
getConfig const config = arc . getConfig ();
Returns the current arc configuration. discardGeometry Disposes of the current geometry (called automatically before regeneration). Properties Unique identifier for the arc instance
Center point of the arc (default: origin)
Radius of the arc (default: 1.0)
Starting angle in radians (default: 0.0)
Ending angle in radians (default: 2π)
Number of segments for tessellation (default: 32)
Internal BREP representation containing vertices, edges, and optionally a face for closed arcs
Arc color (TypeScript only, settable)
Code Examples Creating a Semicircle use opengeometry :: primitives :: OGArc ; use openmaths :: Vector3 ; use std :: f64 :: consts :: PI ; let mut arc = OGArc :: new ( "arc-1" . to_string ()); arc . set_config ( Vector3 :: new ( 0.0 , 0.0 , 0.0 ), // center 5.0 , // radius 0.0 , // start angle PI , // end angle (180 degrees) 32 // segments ); arc . generate_geometry ();
import { Arc , Vector3 } from "opengeometry" ; const semicircle = new Arc ({ center: new Vector3 ( 0 , 0 , 0 ), radius: 5 , startAngle: 0 , endAngle: Math . PI , segments: 32 , color: 0x00ff00 });
Creating a Full Circle use std :: f64 :: consts :: PI ; let mut circle = OGArc :: new ( "circle-1" . to_string ()); circle . set_config ( Vector3 :: new ( 0.0 , 0.0 , 0.0 ), 3.5 , 0.0 , 2.0 * PI , // Full circle 64 // Higher segments for smoother circle ); circle . generate_geometry ();
const circle = new Arc ({ center: new Vector3 ( 0 , 0 , 0 ), radius: 3.5 , startAngle: 0 , endAngle: Math . PI * 2 , segments: 64 , color: 0xff0000 });
Creating a Quarter Arc const quarterArc = new Arc ({ center: new Vector3 ( 5 , 0 , 5 ), radius: 2.0 , startAngle: 0 , endAngle: Math . PI / 2 , // 90 degrees segments: 16 , color: 0x0000ff });
Using Fat Lines for Arcs const thickArc = new Arc ({ center: new Vector3 ( 0 , 0 , 0 ), radius: 10 , startAngle: 0 , endAngle: Math . PI * 1.5 , segments: 48 , color: 0xff00ff , fatLines: true , width: 30 });
Updating Arc Parameters arc . setConfig ({ center: new Vector3 ( 0 , 0 , 0 ), radius: 7.5 , startAngle: Math . PI / 4 , endAngle: Math . PI * 1.75 , segments: 40 , color: 0xffff00 }); // Change color arc . color = 0x00ffff ;
Live Demo
Arc Demo Try the Arc primitive in the browser
See Also
Curve Smooth curves through control points
Line Straight line segments
Polyline Connected line segments
