Troubleshooting

No results are drawn

Results appear only when the model can be solved. Check, in this order:

1. Read the message at the top left of the viewer.
   • No materials defined / No cross sections defined: add one with the Add new button.
   • A blue Needs supports chip: the model is simply unfinished. Add supports. Point at the chip to see, as a dashed outline, how the structure can still move.
   • A red message: something is wrong. It names the problem, or reads Errors in the model: N when there are several. Click Show details and fix each item (see the table below). The nodes or hinges involved are circled on the canvas.
   • A yellow message: warnings. The model was solved anyway; you can hide them.
2. Enough supports? The solver needs at least three restrained DOFs, and the supports must hold the structure. A beam on two rollers (Dz + Dz) has only two and slides away. Add a Dx somewhere, or an Ry at one support.
3. Are the elements connected? Two nodes at the same coordinates are still two separate nodes. Delete the stray one and reconnect, or place nodes on elements with Connect to structure.
4. Too many hinges? Hinges at both ends of a column, or a square of pin-jointed bars without a diagonal, make a mechanism. EduBeam circles the hinges and shows the motion.
5. A stiffness of zero? E, A or Iy accidentally entered as 0, or in the wrong unit, makes part of the structure move almost without resistance. EduBeam reports that as unstable.

Show details lists each problem with a hint, and can show the motion

Messages

Show details opens a dialog titled Cannot solve model (errors), Not ready to solve yet (supports still needed) or Model warnings. Its Troubleshooting link leads here.

Still needed

Message	Meaning / fix
The structure needs supports before it can be solved.	Fewer than three restrained DOFs in total. Add supports.
A separate part of the structure (nodes …) has fewer than 3 restrained DOFs and can move freely.	The model is in pieces and one piece floats. Connect it, or support it.

Errors

Message	Meaning / fix
Structure has enough supports but they do not hold it: it can still …	The supports are all parallel, or their lines of action meet in one point. The dashed outline shows the motion; change the direction of one support. The same message names a separate part if only one piece is affected.
The supports hold the structure, but it is still a mechanism: its members can turn about the hinges at node …	The hinges let members turn against each other, as in a frame with hinges at the top of both columns or a pin-jointed square without a diagonal. Remove a hinge, or add a member or a support.
Structure is unstable: node … moves practically without resistance.	Nearly a mechanism, or a stiffness close to zero. Check supports, hinges, and the values of E, A and Iy.
Structure is a mechanism: the stiffness matrix is singular.	Something can move freely that the checks above did not catch. Check that every part is held by at least three restraints and that hinges do not leave a member free to rotate.
Element … references missing node / material / cross section …	The referenced object was deleted, usually in a hand-edited JSON file. Reassign it in the Elements table.
Element … must reference exactly 2 nodes.	A broken element in an imported file. Delete and recreate it.
Nodal load / Prescribed displacement #n references missing node …	Delete the load or give it a node.
Element load #n references missing element …	Delete the load.
Solver failed due to an internal model inconsistency…	A generic failure. Undo the last step, or save the file and report it.

Warnings

The model is solved anyway, but check these:

Message	Meaning / fix
Node … is not connected to any element and is ignored by the solver.	A stray node. Delete it, or connect it.
Node … is supported but no element connects to it, so the support carries nothing.	A support on a stray node.
Element … references the same node at both ends.	A zero-length element. Delete it.
Nodal load / Prescribed displacement #n contains invalid values.	A component that is not a number. Edit the load.

Results look wrong

Symptom	Likely cause
Loads act upward	Global z points down, so positive Fz/fz is downward. Negative values point up. See conventions. With y-up axes it is the other way round.
Deflection is 1000× too big or too small	A unit mix-up: E entered in Pa while the unit is MPa, or Iy in cm⁴ while the unit is m⁴. Check the units chip at the bottom right of the viewer.
Deflection slightly larger than the textbook formula	Timoshenko shear deformation. Increase the section's shear coefficient, or use a slender member, to approach Euler–Bernoulli values. See Checking results by hand.
A sign looks "wrong"	Read the sign from the labels, not the side of the diagram. Positive M is sagging. End forces in Element results follow the element's local axes, not the N-V-M convention.
Two identical columns show opposite shear signs	The sign of V follows each element's direction. Swap the nodes of one to compare.
Numbers like 4 · 10¹	The scientific number format. Choose Automatic in Settings → Language & Locale → Number format.
Diagrams are huge or tiny	Purely visual. Adjust Results scale in Settings → Viewer settings.
A local-coordinate load points the wrong way	The element's local x runs from its initial to its end node. Swap the nodes, or flip the sign.
An inclined member's load is off	LCS is ticked by default, so fz acts perpendicular to the member. Untick it for a vertical load.
A temperature load does nothing	A determinate structure deforms freely under temperature, without internal forces. Check that α ≠ 0 and, for the gradient, that the section height h is set.

Interface issues

Symptom	Fix
Shortcuts do nothing	Click the canvas first: keys are ignored while a text field has focus.
Cannot pan	Panning uses the middle or right mouse button by default; change it in Settings → Controls & Shortcuts. On a trackpad, two-finger scrolling zooms; click and drag with two fingers to pan.
My model disappeared	Opening a link, a file or an example, and clearing, keep the old model: ☰ → Recent structures, or Ctrl+Z.
Wrong language	Settings → Language & Locale, or add ?lang=en to the address.
Settings changes do not stick	Local storage is blocked (private window, strict privacy mode). Settings, autosave and Recent structures need it.

Reporting a bug

Open a GitHub issue with your browser and OS, what you expected, and, most useful of all, a share link or the project file that reproduces the problem.