> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bedrock.cv/llms.txt
> Use this file to discover all available pages before exploring further.

# Overlays

> Access drawing comparison results.

Overlays are the result of comparing two [Blocks](/cms-api/resources/blocks) from different drawing revisions. They contain aligned images showing additions (green) and deletions (red).

## Endpoints

| Method | Endpoint | Description |
| - | - | - |
| `POST` | [`/drawings/{id}/compare`](/cms-api/overlays/compare-drawings) | Compare two drawings |
| `POST` | [`/sheets/{id}/compare`](/cms-api/overlays/compare-sheets) | Compare two sheets |
| `GET` | [`/overlays`](/cms-api/overlays/list) | List overlays |
| `GET` | [`/overlays/{id}`](/cms-api/overlays/get) | Get overlay details |
| `DELETE` | [`/overlays/{id}`](/cms-api/overlays/delete) | Delete an overlay |

## Overlay Object

| Field | Type | Description |
| - | - | - |
| `id` | string | Unique identifier (e.g., `ovl_01JABCD123`) |
| `block_a_id` | string | Source [Block](/cms-api/resources/blocks) (older revision) |
| `block_b_id` | string | Target [Block](/cms-api/resources/blocks) (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 |


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.