Reference images

blender_compare_reference renders your current geometry through a camera you author and returns one board: the reference, the model's silhouette, and an overlay. Proportion errors become visible without switching between files. It doesn't need the Rust runtime.

#Match the view first

1. Study the reference. Note its crop, perspective, pose, major widths and heights, negative spaces, and visible connections. A single photo doesn't define the back or the depth.
2. Block out and add a camera. Build the primary masses in bpy and add a named camera that matches the reference: orthographic for drawings, perspective for photos.
3. Compare. Save the .blend and call the tool at 256 or 512 pixels.
4. Fix the largest mismatch. Change the source, regenerate, and compare into a new directory with the same camera and crop. Check another angle before accepting an ambiguous depth change.
5. Then refine. Materials and topology come after the primary form matches.

{
  "assetPath": "C:/assets/subject.blend",
  "referencePath": "C:/references/front.png",
  "cameraName": "ReferenceFront",
  "outputDir": "C:/reviews/front-iteration-01",
  "maxEdge": 256
}

Without cameraName, the active camera is used. The tool respects authored visibility, so hide staging floors and unrelated objects.

#Silhouette measurements

Add maskPath for a reviewed silhouette mask: a white subject on black, at the reference's exact dimensions. The overlay then shows shared coverage in green, missing model coverage in pink, and excess in cyan. The report adds intersection-over-union and missing and excess pixel counts.

Photos aren't masks, and the tool never thresholds one. Without a mask, metrics are null and the overlay is for visual review only.

#Landmarks

For points you can identify in both, such as a hinge, a tip, or a corner, pass named correspondences. referenceUv is normalized from the image's top-left corner; localPoint is object-local and defaults to the origin.

{
  "landmarks": [
    { "name": "hinge", "objectName": "HingeAnchor", "referenceUv": [0.32, 0.45] },
    { "name": "tip", "objectName": "Handle", "localPoint": [0, 0, 1], "referenceUv": [0.6, 0.2] }
  ]
}

The report returns a signed pixel offset for each point. With 3 to 32 landmarks, blender_fit_reference_camera fits focal length and lens shift into a candidate .blend, keeping the camera pose and geometry fixed. Compare again before keeping the new values.

#Limits

• One matching projection can hide a bad 3D model. Check complementary views and a normal multiview render.
• Keep the camera, crop, and mask fixed while judging an edit. Changing them makes scores incomparable.
• The tool doesn't reconstruct meshes, estimate camera pose, segment photos, or repair anything. Transparent materials render opaque in this pass.

The reference modeling guide has the full report format.