Fuselage Geometry

The Fuselage model defines the main structural bodies of the UAV. A fuselage is defined as one or more "segments," each consisting of a series of cross-sections connected together.

Structure: Segments and Lofts

The fuselage structure is modular. Multiple "Segments" can be defined under a single fuselage definition. For instance, a fuselage might consist of three separate segments: "Nose Cone", "Main Tube", and "Motor Tower".

Each segment contains a series of cross-sections defined along the X-axis (or any direction in space), which are connected via controlled interpolation (lofting).

Coordinate Frame

Fuselage segments and sections are defined in the SETUAV_BODY frame.

• X-axis: Longitudinal axis.
• Y-Z plane: The plane of the cross-section.

Parameters

Identification and Mass

Parameter	Type	Description
tag	str	Unique identifier for the fuselage (e.g., "main_fuselage").
mass	g	Total fuselage mass.

Geometry: Segments

The fuselage geometry is the sum of parts defined under the segments array. Each segment has the following properties:

Parameter	Type	Description
tag	str	Segment-specific tag (e.g., "nose_cone").
sections	list	List of cross-sections forming the segment (min 2).
blending	object	Surface generation parameters specific to this segment (optional).

Section Properties

Each section has the following properties:

Parameter	Unit	Description
position	object	Section position (required).
position.x	mm	Longitudinal position from the nose.
position.y	mm	Lateral offset from the XZ-plane (optional, default: 0).
position.z	mm	Vertical offset from the XY-plane (optional, default: 0).
profile	object	Cross-section shape definition (required).
rotation	object	Section properties (optional).
rotation.x	deg	Rotation around X-axis (roll, optional, default: 0).
rotation.y	deg	Rotation around Y-axis (pitch, optional, default: 0).
rotation.z	deg	Rotation around Z-axis (yaw, optional, default: 0).

Profile Types

Each section under sections must have a specific profile.

Circle

profile: {type: "circle", diameter: 80}

Ellipse

profile: {type: "ellipse", width: 100, height: 120}

Rectangle

# Can be rounded with optional 'corner_radius'
profile: {type: "rectangle", width: 100, height: 120, corner_radius: 10}

Surface Blending

These parameters control how sections within a segment are connected.

Parameter	Default	Description
ruled	false	If true, connects sections with straight lines (ruled surface).
max_degree	3	Degree of the B-spline surface (1-8).
continuity	G2	Surface continuity target: G0, G1, G2.

Example Configuration

This example defines a Skywalker-style fuselage in two segments: Main tube and motor tower.

tag: "skywalker_X8"
mass: 450
type: "fuselage"
geometry:
  segments:
    # Segment 1: Main Fuselage Line
    - tag: "main_body"
      blending: {ruled: false}
      sections:
        - {position: {x: 0}, profile: {type: "circle", diameter: 5}}  # Pointy nose
        - {position: {x: 200}, profile: {type: "ellipse", width: 150, height: 90}} # Wide body
        - {position: {x: 800}, profile: {type: "circle", diameter: 20}} # Thin tail

    # Segment 2: Motor Tower (Extends from top of fuselage)
    - tag: "motor_tower"
      blending: {ruled: true}
      sections:
        - {position: {x: 600, z: 50}, profile: {type: "ellipse", width: 40, height: 80}} # Tower base
        - {position: {x: 650, z: 120}, profile: {type: "circle", diameter: 40}} # Firewall