Members

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). The code is read in the member's local frame; on a sideways member the releases follow the 90° section roll (see Sideways below).

Tension/Compression Only

Members can be set to carry only tension or only compression. This is useful for modelling diagonal cross-bracing where only the tension diagonal is engaged under each load direction (tension-only), or struts that buckle out of action under reversed load (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.

Because the section is genuinely rolled, everything defined in the member's local frame follows the roll: Local-axis point and distributed loads, thermal gradients, end releases, and the transverse components of a Local end-eccentricity offset all rotate 90° with the section so they keep acting on the cross-section as drawn — a Local Y load, a release about local y, or a top-of-section eccentricity follows the rolled section, and the on-canvas glyphs roll to match. Global-axis loads and Global eccentricity offsets are unaffected.

End Eccentricity

The Eccentricity section in the Properties panel lets you offset the structural endpoints of a member from the joint nodes you drew. This mirrors the “Member Eccentricity” / “Insertion Point” / “Joint Offsets” feature found in other FEA tools, and produces a true textbook M = N · e moment from any axial force.

For each end (A and B) you can enter an offset vector with x, y and z components in the active length unit. Choose between two reference axes:

• Local axes (default) — interpreted in the member's own coordinate frame: x along the member from i to j, y and z the two transverse directions. On a sideways member the transverse y / z follow the section's 90° roll, so a top-of-section offset stays on the rolled top. Use this when the offset is described relative to the member (e.g. “0.3 m along the beam to clear the column face”).
• Global axes — straight global X / Y / Z. Use this when the offset is defined by surrounding geometry (e.g. “this brace's structural line sits 0.3 m below the top chord”).

The 3D viewer shows a thin dashed line from each joint to its offset endpoint and an ECC chip at the member midpoint so you can see at a glance where the structural line actually runs. Member force diagrams, the deflected shape, and member loads all ride along the offset line, and design-check member lengths use the offset-adjusted length too.

Clearing every axis of the offset (or typing 0 in each box) removes the eccentricity entirely and the member reverts to bit-identical behaviour with a non-eccentric beam.

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.