Line Charts

Line charts display data as a continuous 3D line connecting data points, where each point's vertical position represents a numeric value and its horizontal position represents a category or sequential index. Hydrant renders lines as 3D tubes or beams with configurable thickness, color, animation, and cross-section shape.

Overview

A line chart scene is built from one or more dataset selections. Each selection produces a single line entity — a polyline connecting all data points in order. Multiple selections create multiple lines that can share the same X-axis through alignment settings.

Entity Hierarchy

Line chart scenes use the following entity structure:

Data Container — Top-level group that holds all dataset selections
- Line Group (one per selection) — Groups the line from a single selection; carries the selection's transform (position, rotation)
  - Line — The polyline entity with point data, color, and width
- Line Group (second selection, if present) — Another line from a second dataset
Graph Block — Optional L-shaped container (ground + back wall)
Grid / Scale — Optional axis lines and numeric labels

Line Appearance

These settings are configured per dataset selection in the Data panel under Line Settings.

Line Width — Thickness of the line (0.01 – 0.5). Controls the tube radius or beam size in world units.

Line Color — Color of the line. Each selection can have its own color.

Line Style — Cross-section shape of the line:

Round — Cylindrical tube shape (default). Creates smooth, organic-looking lines.
Square — Rectangular beam shape. Creates sharper, more geometric lines that pair well with grid-heavy designs.

Point Spacing — Distance between data points along the X-axis (0.01 – 3.0). Smaller values create compact lines; larger values spread data points apart. This setting is hidden when multi-dataset alignment is enabled, since the global alignment spacing takes precedence.

Scale & Value Mapping

The Y-axis scale determines how data values map to vertical positions on the line. Scale settings are configured in the Data panel and work identically to bar charts.

Scale Mode:

Zero-Based (Include 0): Y-axis starts at 0
Data Range (Fit to Data): Y-axis spans from minimum to maximum data value
Manual Range: Custom minimum and maximum values

When multiple selections share a scene, the scale is computed globally so all lines use the same value range, making them directly comparable.

Colors

Line color is set per selection in the Data panel under Line Settings. Unlike bar charts (which can assign colors per data point), each line is rendered as a single continuous color.

Per-line color overrides can be applied via the Scene Tree (Object Inspector) on the line entity.

Animation

Line charts use a draw-on animation where the line progressively reveals from left to right, as if being drawn by an invisible pen.

Animation timing is configured per selection in the Data panel under Animation Timing.

Animation Type:

Staggered (One after the other) — When multiple lines exist, each line begins its draw-on animation after the previous line has finished (or started, depending on timing). This creates a sequential reveal.
Delayed — All lines animate simultaneously with a configurable delay between them.
Not Animated — Lines appear fully drawn immediately.

Delay Before — Pause before the line begins drawing (0.0 – 5.0 seconds).

Delay After — Pause after the line finishes drawing (0.0 – 5.0 seconds).

Draw-On Behavior

The draw-on animation uses arc-length based progress, meaning the line reveals at a uniform visual speed along its path regardless of how data points are spaced. At 50% progress, exactly half the total line length is visible — not half the data points. This ensures smooth, consistent animation even when data points are unevenly distributed.

Labels

Labels for line charts are configured in the Labels panel. Line charts support all standard label types:

Value Labels — Show the numeric value at each data point along the line
Category Labels — Show category names below the data points
Scale Labels — Appear on the Y-axis
Custom Labels — User-defined, freely positioned or data-linked

Anchor Points

Value and category labels can be anchored to specific positions relative to each data point:

Value — Attaches at the data point's actual Y position on the line (default for value labels)
Bottom — Attaches at the baseline (Y = 0)

During animation, labels for data points that have not yet been drawn remain hidden and appear as the line reaches each point.

Graph Block

The graph block is an optional L-shaped container configured in the Scene panel. It provides spatial context for the line and serves as a mounting surface for the scale.

Grid and Scale

Grid lines and scale numbers provide visual reference for reading values. These are configured in the Scene panel.

Interaction

In the 3D editor, line chart scenes support the following interactions:

Click a line group in the Scene Tree to select it. The selected group shows a bounding box wireframe and anchor points.
Hover over entities in the Scene Tree to highlight them.
Data Container — Select the data container to see the combined bounding box of all line groups, with anchor points at the 27 bounding box positions (combinations of Left/Center/Right, Bottom/Middle/Top, Back/Center/Front).

Multi-Dataset Support

Line charts excel at comparing multiple datasets. A single scene can display multiple lines from different selections, overlaid on the same axes.

Alignment

When multiple selections are present, the Multi-Dataset Alignment section in the Data panel controls how lines are positioned relative to each other.

Enable Alignment — Toggle alignment mode. Enabled by default when multiple selections exist.

Matching Axis — The column used to align data points across datasets (e.g., "Year", "Date"). Set to "Auto" by default, which detects the shared column. When alignment is enabled, data points with the same category value across different selections are placed at the same X position.

Point Spacing — Distance between aligned data points (0.01 – 3.0). This global spacing overrides per-selection point spacing.

Sync Animation — Synchronize animation timing across all datasets so all lines draw on at the same pace. Enabled by default.

The alignment section also displays match statistics showing unique categories, per-selection stats, and overlap percentage between datasets.

Independent Lines

When alignment is disabled, each line group uses its own X-axis spacing and can be positioned independently using the per-selection Transform settings (position, rotation).

Entity Overrides

Line groups and individual line entities can be customized through the Object Inspector in the Scene Tree:

Position — Offset the line from its computed position
Rotation — Rotate the line group
Scale — Resize the line group
Color — Override the line color
Visibility — Show or hide the line
Opacity — Adjust line transparency

Overrides persist across data reprocessing.