[bar-3d-categorical] 3D Bar Chart for Categorical Comparison

[MarkusNeusinger]

Description

A three-dimensional bar chart where bars rise from a 2D categorical grid, with height encoding the value. Two categorical axes define the grid position and the vertical axis shows magnitude. This extends the existing bar chart family into 3D space, complementing scatter-3d, surface-basic, and wireframe-3d.

Applications

• Comparing sales across product categories and regions simultaneously
• Displaying survey responses across two demographic dimensions
• Showing experimental results with two categorical factors
• Visualizing frequency tables with two grouping variables

Data

• x_category (str) — first categorical dimension
• y_category (str) — second categorical dimension
• value (float) — bar height
• Size: 3–10 categories per axis

Notes

• Bars should have slight spacing for clarity
• Color can encode value or a third variable
• Adjustable viewing angle for best perspective
• Grid lines on the base plane for reference

[claude]

✅ Spec ID: bar-3d-categorical

Rationale: Extends the bar chart family into 3D space with two categorical axes forming a grid and bar height encoding values — no existing 3D bar spec exists. The -categorical modifier distinguishes this from a simple extruded bar chart by emphasizing the dual-category grid layout.

Valid and useful plot type. No duplicates or similar specs found among the 15 existing bar variants or 4 existing 3D specs.

[claude]

✅ Spec ID: bar-3d-categorical

Rationale: Combines the bar plot type with 3D rendering and two categorical axes forming a grid — distinct from all existing 2D bar variants and other 3D specs (scatter-3d, surface-basic, wireframe-3d-basic). Valid and useful plot type for multi-dimensional categorical comparison.

[github-actions]

✅ Specification Ready: bar-3d-categorical

PR: #5267

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specification.md

bar-3d-categorical: 3D Bar Chart for Categorical Comparison

Description

A three-dimensional bar chart where bars rise from a 2D categorical grid, with height encoding the measured value. Two categorical axes define the grid position on the base plane while the vertical axis shows magnitude. This visualization extends the bar chart family into 3D space, making it effective for comparing values across two categorical dimensions simultaneously.

Applications

• Comparing sales figures across product categories and geographic regions simultaneously
• Displaying survey responses across two demographic dimensions (e.g., age group vs education level)
• Showing experimental results with two categorical factors in factorial designs
• Visualizing frequency tables or cross-tabulations with two grouping variables

Data

• x_category (str) - first categorical dimension (e.g., product type, region)
• y_category (str) - second categorical dimension (e.g., time period, segment)
• value (float) - bar height representing the measured quantity
• Size: 3-10 categories per axis, forming a grid of 9-100 bars

Notes

• Bars should have slight spacing between them for visual clarity and depth perception
• Color can encode the value magnitude or a third categorical variable
• Viewing angle should be adjustable; a default elevation of ~30 degrees and azimuth of ~45 degrees provides good readability
• Grid lines on the base plane help relate bars to their categorical positions
• Consider adding value labels on top of bars when the grid is small (under 25 bars)
• A color bar or legend should indicate the mapping when color encodes a variable

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Next: Add approved label to merge this specification to main.

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