Members

Members are the structural elements that connect nodes. They represent beams, columns, braces, and any linear structural element in your model.

What are Members?

Each member is defined by:

  • Start and end nodes - The two points the member connects
  • Section - The cross-sectional shape and properties
  • Material - The material properties (steel, timber, etc.)
  • End releases - How the member connects to its nodes (rigid or pinned)

Creating Members

Members are created automatically in Draw mode:

  1. Press D or click the Draw tool to enter Draw mode
  2. Click to place the start node
  3. Click again to place the end node - a member is created between them
  4. Continue clicking to create connected members
  5. Press Escape to finish the chain

Click on an existing node to start a new chain from that point.

Member Properties

Select a member to view and edit its properties in the Properties panel:

Section

The cross-sectional shape determines structural behaviour. Select from the dropdown or click the book icon to open the Section Library.

Material

The material defines stiffness (Young's Modulus) and density for self-weight. Select from the dropdown or click the book icon to open the Material Library.

End Releases (Member Fixity)

Control how the member connects at each end. The Properties panel shows i-end and j-end fixity controls with preset options:

  • Fixed (FFFFFF) - Fully rigid connection (default)
  • Pinned - Rotations released at that end

The 6-character code represents: Dx, Dy, Dz, Rx, Ry, Rz (F = Fixed, R = Released).

Member Orientation

Each member has a local coordinate system:

  • Local x-axis - Along the member length (from i-node to j-node)
  • Local y-axis - Minor bending axis (typically vertical for horizontal members, but represents the direction of vertical load)
  • Local z-axis - Major bending axis (typically horizontal, axis of rotation for primary bending)

Results like bending moments and shear forces are reported in the local coordinate system.

Tension/Compression Only

Members can be set to carry only tension or only compression. This is useful for modelling cables (tension-only) or struts that buckle (compression-only). Set this property in the Properties panel when a member is selected.

Sideways (Section Rotation)

The Sideways toggle rotates the cross-section 90° about the member's longitudinal axis. This is useful when you need to orient an I-beam with its web horizontal (e.g., for a lintel or spandrel beam). Toggle it in the Properties panel when a member is selected.

Loads

When a member is selected, the Properties panel provides a Loads section with quick-access buttons to open the load dialogs for the selected member. You can apply node loads to either end, or distributed/concentrated loads along the member length.