User Interface

Calculus has a straightforward layout: a large 3D workspace with panels around the edges for tools, properties, and menus. This page explains each part of the interface.

3D Viewport

The main area of the screen is your 3D model workspace. This is where you see your structural model and interact with it — creating objects, selecting them, and editing their geometry.

Camera

The viewport uses an orthographic camera (no perspective distortion), which is standard for structural engineering work. The Z-axis points up, matching structural engineering conventions.

Navigation

Action	Mouse	Touch
Rotate the view	Right-click + drag	Two-finger rotate
Pan (move sideways)	Middle-click + drag	Two-finger drag
Zoom	Scroll wheel	Pinch

Additional view controls:

• Press Home to fit the entire model in the viewport
• Press V, then click a point to set the rotation center — the view will orbit around that point
• Use View → Smooth Camera to enable smooth transitions when rotating and panning

Work Plane

The work plane is the flat surface where new objects are created when you click in the viewport. By default, this is the global XY plane at ground level (Z = 0).

You can reposition it to work at different levels or angles:

• Set by 3 points — Click three points to define a custom plane
• Set by object — Align the work plane to an existing beam or plate
• Reset to global — Return to the default ground-level plane

These commands are available in the Command Palette (Ctrl+K, then search "work plane").

Snap Points

When you're placing or editing objects, the cursor automatically snaps to precise points on existing geometry. You'll see a visual indicator when a snap is active.

Snap type	What it snaps to
Origin	Object insertion points
End	Endpoints of beams, plate edges, lines
Mid	Midpoints of edges and beam axes
Cross	Intersections between two objects
Ortho	Points along horizontal/vertical axes from a reference point
Near	Nearest point on an edge or line
Axis	Points along the global X, Y, or Z axis from a reference

Snapping is always active during creation and editing commands. This ensures your model geometry is precise without having to type coordinates.

Selection

Single selection: Click on an object to select it. It highlights, and its properties appear in the sidebar.

Multi-selection: Hold Ctrl and click to add or remove objects from the selection.

Area selection: Click and drag on empty space to draw a selection box:

• Drag left to right → selects objects fully inside the box
• Drag right to left → selects objects that touch or are inside the box

TIP

This left-to-right vs. right-to-left selection behavior is the same as in Tekla Structures and AutoCAD.

Handle selection: Hold Alt while dragging a selection box to select individual handles (control points) on objects instead of the whole object. This is useful for editing individual vertices of a plate or endpoints of a beam.

Handles

When you select an object, you'll see handles — small control points on its geometry:

• Point handles on beam endpoints, plate vertices, and bolt reference points
• Line handles on edges
• Face handles on surfaces

To move a handle, select it (using Alt + area select, or clicking directly on a handle), then press M to start the move command.

Menu Bar

The menu bar sits in the top-left corner with four menus:

File

Command	Shortcut	What it does
Open file	Ctrl+O	Open a .calculus model, catalog file, IFC, or 3D reference file
Save as	Ctrl+S	Download the model as a .calculus file
Clear model	—	Remove all objects from the model (asks for confirmation first)
Export IFC 4x3	—	Export the model (or selected objects) to IFC format
Theme	—	Switch between Light, Dark, and System themes
Background color	—	Change the viewport background color

Edit

Command	Shortcut	What it does
Undo	Ctrl+Z	Undo the last action (up to 30 steps)
Redo	Ctrl+Y	Redo the last undone action
Move	Ctrl+X	Move selected objects
Copy	Ctrl+C	Copy selected objects
Delete	Delete	Delete selected objects

View

Command	Shortcut	What it does
Fit model in view	Home	Zoom to show the entire model
Representation	—	Switch between Solid and Wireframe display
View filter	—	Show or hide specific object types (beams, plates, bolts, etc.)
Profile chamfers	—	Show or hide fillet/chamfer details on extruded profiles
Smooth camera	—	Enable or disable smooth camera transitions
Zen mode	—	Hide all panels for a distraction-free view of the model

Library

Opens the management dialogs for your catalogs:

• Profile Catalog — Steel sections and custom profiles
• Material Catalog — Steel, concrete, timber, and other materials
• Bolt Catalog — Bolt assemblies and components
• Rebar Catalog — Reinforcement bar grades and sizes

See the Catalogs page for details.

Toolbar

The horizontal toolbar at the top-center of the screen provides quick access to all object creation tools. Each button has a keyboard shortcut shown below.

Tool	Shortcut	What it creates
Beam	1	Beams and columns
Plate	2	Plates and gussets
Cut Part	3	Boolean cuts (openings, notches, copes)
Cut Plane	4	Trimming planes
Bolt	5	Bolt groups
Weld	6	Welds
Rebar	7	Reinforcement bars
Grid	8	Structural reference grids
Line	L	Construction lines
Comment	9	Text comments
Mark	M	Labels
Dimension	D	Dimensions

Hint Panel

The hint panel sits below the toolbar and gives you context-sensitive guidance:

• When no command is active: "Press Ctrl+K to open command palette"
• During point picking: "Pick the start point", "Pick the end point"
• When handles are selected: "You can move selected handles with M"

You can toggle hints on or off in the File menu.

Property Sidebar

The collapsible panel on the right side of the screen. It has tabs:

Properties Tab

When one or more objects are selected, this tab shows all their editable properties:

• Profile — Cross-section for beams, thickness for plates
• Material — Material assignment
• Class — Color classification (0–14, same convention as Tekla Structures)
• Position — Vertical and horizontal positioning (top/center/bottom, left/center/right) with offset values
• Geometry — Start/end points, vertices, angles
• Connection details — Bolt standards, sizes, grades, weld shapes and sizes
• Numbering — Part mark prefix and starting number
• User-defined attributes — Custom key-value data you can attach to any object

When multiple objects of the same type are selected, you can edit shared properties in bulk.

Models Tab

Manage what's loaded in the model space:

• View the current structural model
• Add, remove, or toggle visibility of analytical models
• Add, remove, position, or toggle visibility of reference models (IFC, glTF, PLY overlays)

Notifications Tab

Shows application messages (success, warnings, errors). A badge shows unread notifications.

Command Palette

Press Ctrl+K anywhere to open a searchable list of all commands. Start typing to filter (e.g., "mirror", "bolt", "work plane"), use arrow keys to highlight, and press Enter to run it. Each command also shows its keyboard shortcut if one exists.

This is the fastest way to access any command you don't remember the shortcut for.

Status Bar

The thin bar at the bottom-left shows:

• How many objects and handles are currently selected
• A loading spinner when background operations are running

Display Options

Solid vs. Wireframe

Switch between Solid (filled) and Wireframe (edges only) representation using the View menu. Wireframe is useful for seeing inside dense structures.

View Filter

In the View menu, you can toggle visibility for each object type individually. For example, hide bolts and welds to focus on the steel frame, or hide everything except rebar to review reinforcement.

Zen Mode

Hides the menu bar, toolbar, and status bar — leaving only the 3D viewport and the property sidebar. Useful for presentations or when you need maximum screen space for the model.

Themes

Choose from Light, Dark, or System (matches your OS setting) themes. You can also customize the viewport background color independently.