Overlays - Bedrock

Overlays are the result of comparing two Blocks from different drawing revisions. They contain aligned images showing additions (green) and deletions (red).

Endpoints

Method	Endpoint	Description
`POST`	`/drawings/{id}/compare`	Compare two drawings
`POST`	`/sheets/{id}/compare`	Compare two sheets
`GET`	`/overlays`	List overlays
`GET`	`/overlays/{id}`	Get overlay details
`DELETE`	`/overlays/{id}`	Delete an overlay

Overlay Object

Field	Type	Description
`id`	string	Unique identifier (e.g., `ovl_01JABCD123`)
`block_a_id`	string	Source Block (older revision)
`block_b_id`	string	Target Block (newer revision)
`job_id`	string	Comparison job that created this overlay
`uri`	string	Combined overlay image URL
`addition_uri`	string	Additions-only image URL
`deletion_uri`	string	Deletions-only image URL
`aligned_a_uri`	string	Aligned source block image
`aligned_b_uri`	string	Aligned target block image
`score`	number	Similarity score (0-1, lower = more changes)
`summary`	object	Change statistics
`changes`	array	Detected changes (after change detection)
`created_at`	datetime	Creation timestamp

Similarity Scores

Score	Interpretation
0.95+	Nearly identical, minor changes
0.80-0.95	Moderate changes
0.60-0.80	Significant changes
< 0.60	Major revisions or different content