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Polylines in Bitbybit

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View Full Source & Details on GitHub

The Polyline class in Bitbybit provides tools for working with polylines, which are essentially paths or sequences of connected straight line segments.

What is a Polyline in Bitbybit?

A polyline in Bitbybit is typically represented as an object with a points property. This property holds an array (a list) of 3D points [x, y, z]. { points: [[x1,y1,z1], [x2,y2,z2], [x3,y3,z3], ...] }

A polyline can also be isClosed, meaning there's an implied segment connecting the last point back to the first point, forming a closed loop or polygon outline.

Core Capabilities of the Polyline Class​

The Polyline class helps you define, analyze, and manipulate these sequences of points. Here's a high-level look at its features. For the exact input parameters (like DTOs) and detailed behavior, please refer to the full Polyline API documentation or the GitHub source linked above.

1. Creating Polylines​

  • From Points (create()): The primary way to create a polyline is by providing a list of its points. You can also specify if the polyline should be considered closed.

2. Getting Information About Polylines​

Understanding your polyline's properties:

  • Points (getPoints()): Retrieve the list of points that make up the polyline.
  • Length (length()): Calculate the total length of the polyline by summing the lengths of all its segments.
  • Number of Points (countPoints()): Get the total count of points in the polyline.

3. Modifying and Transforming Polylines​

Changing existing polylines:

  • Reverse (reverse()): Reverse the order of points in the polyline. This effectively flips its direction.
  • Transform (transformPolyline()): Apply a 3D transformation (like translation, rotation, scaling) to all points of the polyline.

4. Converting Polylines​

Changing the representation:

  • To Line Segments (polylineToLines(), polylineToSegments()): Convert a polyline into a list of individual line segments.
    • polylineToLines() returns a list of line objects ({start, end}).
    • polylineToSegments() returns a list of segment arrays ([[startPt], [endPt]]).
    • If the polyline isClosed, an additional segment connecting the last point to the first is included (unless they are already the same point).

5. Intersection (Advanced)​

Finding where polylines cross:

  • Self-Intersection (polylineSelfIntersection()): Find all points where a polyline crosses over itself. This does not consider intersections between adjacent segments.
  • Two Polyline Intersection (twoPolylineIntersection()): Find all points where two different polylines intersect each other.
    • Both intersection methods use a tolerance to account for floating-point inaccuracies.

6. Organizing and Sorting (Advanced)​

  • Sort Segments into Polylines (sortSegmentsIntoPolylines()):
    • A powerful utility that takes a collection of potentially disconnected and unordered line segments.
    • It attempts to connect these segments end-to-end (within a tolerance) to form one or more continuous polylines.
    • It can identify both open and closed polylines from the input segments.

7. Fillet Calculations (Advanced Geometry)​

  • Max Fillet Radii (maxFilletsHalfLine()): For each corner (vertex) of the polyline, calculate the maximum possible radius for a smooth, rounded fillet that can be applied, based on a "half-line" constraint (tangent points within the first half of each segment).
  • Safest Fillet Radius (safestFilletRadius()): Determine the single smallest fillet radius from the maxFilletsHalfLine results. This is the largest radius that could be applied uniformly to all corners of the polyline without overlaps, given the half-line constraint.