Nodes & supports
Nodes are the points of the model. Elements connect nodes; supports and nodal loads are attached to nodes.
Coordinates
Every node has an X and a Z coordinate in the current length unit. The x axis points right and the z axis points down on screen—so a column from the ground up runs from Z = 0 to Z = −3, not +3. The axis indicator in the corner of the grid shows the current orientation. See Coordinate system & sign conventions.
Adding nodes
| Method | How |
|---|---|
| Dialog | Nodes tab → Add node, or right-click the canvas → Add node. Enter X and Z. |
| Mouse | Nodes tab → Add using mouse (or hold Ctrl while choosing Add node from the canvas menu), then click on the canvas. Each click adds a node; press Esc to stop. |
| While drawing elements | In Add element → Add using mouse mode, clicking empty canvas creates a new node and connects it. |
| Copy & paste | Select nodes (and elements), Ctrl+C, Ctrl+V, then click where the copy should go. |
Labels are assigned automatically (1, 2, …) and can be renamed in the table.
Snapping
With Snap to grid on (S or the S chip) mouse-placed and dragged nodes land on multiples of the Grid snap step (default 0.1 m, changeable in Settings → Viewer settings → Grid). Turn snapping off for free placement, or type exact coordinates in the table afterwards.
Placing a node on an existing element
If you click within ~0.1 m of an element while adding a node, EduBeam asks what you mean:
- Connect to structure — the element is split into two (
1aand1b), hinges at the outer ends are preserved and any distributed load is divided between the halves. This is the quickest way to add an interior support or a load point. - Place individual node — the node is created on top of the element but not connected to it.
Editing nodes
- Table: edit label, X and Z in place.
- Drag: move a node in the viewer (undoable). On touch screens, long-press a node to start moving it.
- Edit node dialog: coordinates, supports and the LCS angle in one place, with a live preview of the support symbol.
- Delete: the trash icon in the table, Delete in the node's popover, or select and press Delete. Deleting a node deletes the elements and loads attached to it.
Supports
A support is simply a set of restrained degrees of freedom (DOFs). Each node has three:
| DOF | Meaning |
|---|---|
| Dx | translation along x (horizontal) |
| Dz | translation along z (vertical) |
| Ry | rotation about y (in-plane rotation) |
Tick the boxes in the Supported DOFs column of the Nodes tab, in the Node supports popover of a selected node, or in the Edit node dialog. The symbol drawn in the viewer follows from the combination:
| Restrained | Support | Symbol |
|---|---|---|
| Dx + Dz + Ry | Fixed (clamped) | hatched block |
| Dx + Dz | Pinned | triangle |
| Dz | Vertical roller (free to slide horizontally) | triangle on rollers |
| Dx | Horizontal roller (free to slide vertically) | rotated roller |
| Dz + Ry | Sliding clamp (vertical guide) | clamp on rollers |
| Dx + Ry | Sliding clamp (horizontal guide) | rotated clamp |
| Ry | Rotational restraint only | rotational clamp |
| none | Free node | — |
A reaction is computed—and drawn—for every restrained DOF.
Truss joints
Truss members are beam elements with both end hinges released (see Elements). A pinned support (Dx + Dz) at a truss joint is the usual choice; do not restrain Ry at a node where every connected element is hinged, otherwise the rotation of that node is undefined.
Inclined (skewed) supports
Set Nodal LCS angle (degrees, −180…180) in the node popover or the Edit node dialog. The node's local axes rotate by that angle and the support DOFs are interpreted in the rotated system, so a roller on a 30° slope is Dz with an LCS angle of 30. The support symbol rotates accordingly and the reaction is reported in the rotated direction.
Stability
The solver needs at least three restrained DOFs in total and a mechanism-free structure. Missing or insufficient supports produce the error Model needs at least 3 constrained DOFs… or simply no results. See Troubleshooting.
Nodal loads and settlements
Forces, moments and prescribed displacements (support settlements) are applied at nodes—see Loads.
Dimension lines
Right-click the canvas → Add dimension to draw a dimension line between two points. End points snap to nodes when dragged close to them; select the line and use Edit to type coordinates or Flip dimension to put the label on the other side. Dimension lines are cosmetic and are saved with the project.