TALA

Proprietary layout engine developed by Terrastruct, designed specifically for software architecture diagrams.

TALA is a separate install from D2, to keep a clean cut between 100% free and open-source D2, and proprietary, closed-source TALA. You can download it here: https://github.com/terrastruct/tala.

Reference

https://terrastruct.com/tala/

Pros

• As a general orthogonal layout engine, TALA is not constrained to one type like hierarchies or trees or radial. For fundamentally non-hierarchical layouts, TALA can produce diagrams like a human would on a whiteboard.
• top and left can be used to lock positions.
• Considers and prefers symmetry.
• First-class consideration for containers.
• direction can be set per-container.
• near can be specified to be to another shape.
• sql_table connections point to exact row.
• Dynamic label positioning to avoid obstructions.
• Connections for grid cells use TALA's routing engine instead of always straight lines.

Cons

• Not free.
• Relatively new. ~2 years in production compared to the 10+ years that alternative layout engines have.
• More random than other layout engines. A small change to a label can cascade into an entirely different layout.

Gallery

Using a different seed

TALA's core algorithms use randomness in its initial placements and iterations. If you are not satisfied with a layout, you can produce different ones by specifying the seed with --tala-seed flag. For example, these are the same diagrams as the above, with --tala-seed=2.