Result Types

AutoCalcs provides a comprehensive set of analysis results to help you understand your structure's behavior under load. Results can be viewed visually on the 3D model.

Displacement

Deformation of the structure

Shows how the structure moves from its original position. Displacements include:

  • Translation (Dx, Dy, Dz) - Movement in X, Y, Z directions
  • Rotation (Rx, Ry, Rz) - Rotation about X, Y, Z axes

The visual display shows the deformed shape of the structure, usually magnified so you can see the behavior patterns. Member deflection is drawn as a lightweight line overlay; labels and hover readouts show displacement magnitudes where available.

Reactions

Support forces

Forces and moments that the supports exert on the structure to maintain equilibrium. By Newton's third law, the loads transferred to the foundation are equal in magnitude and opposite in direction.

  • Forces (Fx, Fy, Fz) - Reaction forces in global directions
  • Moments (Mx, My, Mz) - Reaction moments (for fixed supports)

Displayed as arrows at support nodes. Arrow direction indicates force direction.

Axial Force

Member internal force along its axis

The force stretching or compressing a member.

  • Positive (+) - Tension (stretching)
  • Negative (-) - Compression (squashing)

Displayed as a diagram along the member length. Important for designing trusses, columns, and bracing.

Shear Force

Member internal force perpendicular to axis

Forces trying to slice the member.

  • Vy (Major Shear) - Shear force in the local y-direction (typically vertical shear for beams)
  • Vz (Minor Shear) - Shear force in the local z-direction (typically horizontal shear)

Displayed as a filled diagram perpendicular to the member axis.

Bending Moment

Internal bending resistance

The moment causing the member to bend.

  • Mz (Major Moment) - Moment about the local z-axis (typically causing vertical bending). This is the primary moment for floor beams.
  • My (Minor Moment) - Moment about the local y-axis (causing sideways bending).

Displayed as a filled diagram drawn on the tension side of the member.

Torsion

Twisting moment

The internal twisting moment about the member's own longitudinal axis (Mx). It arises wherever load is applied away from the shear centre, on curved or cranked members, or where one end is held against rotation while the rest twists.

This is uniform (St. Venant) torsion, resisted by the section's torsion constant J and shear modulus G. Warping (non-uniform) torsion is not modelled. For open thin-walled sections such as I-beams, channels, angles and tees that are restrained against warping at their ends, two things follow: the true torsional stiffness is higher than J alone, so the reported rotation can be larger than reality, and the warping normal stresses (which often govern torsion in these shapes) are not included in the results. Run a separate torsion check to your design code for such members, and note that the built-in steel design checks cover torsion for closed hollow sections only. Closed sections (hollow tubes and boxes) carry torsion almost entirely through St. Venant shear, so this result applies to them directly.

Member Stress

Elastic member stress contour

Colours members from the solved member forces and section geometry. In rendered and outlined views, the per-fibre quantities are evaluated over the member surface; in wireframe view, and for uniform or station-based quantities, the display is a continuous station gradient along the member. Turn it on from the left sidebar and right-click the button to choose the quantity:

  • Combined Stress (Axial + Bending) (default) - signed elastic normal stress from axial force plus biaxial bending at each fibre: σ = P/A + Mzy/Izz + Myz/Iyy. It does not include shear or torsion; use Total Shear, Von Mises, Tresca or Rankine for quantities that include shear/torsion effects.
  • Axial - uniform axial stress, P/A.
  • Bending Stress Magnitude - absolute bending-only normal-stress component at the governing fibre, excluding axial, shear, and torsion.
  • Torsional Shear Stress - Saint-Venant torsional shear from T and J. Closed and solid sections use outer-fibre shear; open thin-walled sections use wall-thickness shear. Warping torsion is not included; see Torsion above.
  • Total Shear - combined transverse and torsional shear at the worst cross-section point.
  • Principal σ₁ / σ₂ - the maximum and minimum in-plane principal stresses.
  • Von Mises Stress - distortion-energy equivalent stress (ductile metals).
  • Tresca Stress - maximum-shear equivalent stress (ductile, conservative).
  • Rankine Stress - maximum tensile principal stress (brittle materials, e.g. concrete/masonry).

A colour legend in the bottom-right shows the value range in your unit system (MPa or ksi). Signed quantities (Combined, Axial, σ₁, σ₂) follow the model convention, with tension in blue and compression in red. Magnitude/equivalent quantities use a low-to-high ramp and do not imply compression or tension by colour. Hover over a rendered or outlined member to read the stress at the cross-section fibre under the cursor for the per-fibre quantities: Combined, Bending Stress Magnitude, Torsional Shear Stress, σ₁/σ₂, Von Mises Stress, Tresca Stress, Rankine Stress and Total Shear.

These are elastic beam-theory post-processing stresses recovered from the solved 1D member forces. They are member-level stresses, not a local shell/solid stress analysis of the web, flange, support, load-introduction, weld, bolt, or connection region. They do not include local stress concentrations, flange/web junction effects, bearing effects, fillet/root-radius hot spots, or warping normal stresses. For steel, normal stress and the ductile-metal equivalent stress quantities are suitable for engineering review within the usual beam-element assumptions. Von Mises and Tresca are ductile-metal yield criteria, so they are greyed out for concrete and timber members; Rankine Stress (max tensile principal) is the appropriate elastic brittle-material criterion. For concrete and timber the stresses are indicative only: they show the gross-section elastic stress field but are not a capacity check. Concrete member stress contours use the concrete shape geometry and section properties only; they do not include reinforcing bars, cracked-section behaviour, transformed-section properties, strain compatibility, or code stress-block design.

Plate Result Contours

... Plate result contour

Colours plate elements by the selected plate result quantity. Use the left sidebar contour button after analysis, then right-click it to choose what the contour shows.

  • Deflection - resultant or vertical plate displacement.
  • Bending - plate moments such as Mx, My, Mxy, and principal moments.
  • Transverse shear - Qx and Qy in the plate local directions.
  • Membrane and fibre stress - signed membrane stress, principal stresses, and top/bottom-fibre equivalent stresses: von Mises, Tresca, Bach and Rankine.
  • Wood-Armer - unsigned concrete plate design-moment demands for top (+local z face) and bottom (-local z face) reinforcement layers.

The contour legend appears in the viewport and uses the current unit settings. Smooth and banded display modes change only how the field is drawn; they do not change the solved plate results.

Units

Results are displayed in your currently selected unit system (Metric or Imperial).

Metric (SI)

  • Displacement - mm or m
  • Force (Axial, Shear, Reactions) - kN
  • Moment (Bending, Torsion) - kN·m

Imperial (US)

  • Displacement - in or ft
  • Force - kip or lbf
  • Moment - kip·ft or lb·ft

You can change unit settings at any time in the Settings dialog.

Result Sign Conventions

Member Internal Forces

Internal forces follow the member's local coordinate system:

  • Axial - Tension is positive
  • Shear - Positive shear acts in positive local y/z direction on a positive face
  • Moment - Positive moment acts counter-clockwise about local axis (Right Hand Rule)

Reactions

Reactions follow the global coordinate system:

  • +Fy - Upward reaction force
  • +Fx - Reaction to the right