Create blob trace
create_blob_traceTrace contour of blob or silhouette from camera, movie, or synthetic source into vector line art with adjustable threshold, blur, and line width.
Instructions
Trace the contour/outline of a blob or silhouette into vector line art: source → monochrome → blur → threshold (the blob mask, optionally inverted) → optional Edge (boundary-band only) → Trace SOP (mask-to-polyline) → wireframe render. This is the CONTOUR-TRACE complement to create_vector_lines (full image vectoriser) and export_sop_to_svg, and is distinct from create_blob_reactive (which tracks blob position/reactivity — it does not draw the outline). Source can be the live camera (may prompt for macOS permission), a movie file, an animated synthetic blob (testable without a camera), or an existing TOP. Creates a new baseCOMP under parent_path. Exposes Threshold, Blur, and LineWidth controls. Returns a summary plus a JSON block with the container path, created node paths, output path, exposed controls, node errors, warnings, and an inline preview image.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| invert | No | Invert the mask so dark regions become the traced blob instead of bright ones. | |
| source | No | Blob source. 'camera' = live webcam (may prompt for macOS camera permission). 'file' = a movie file (movie_file_path). 'synthetic' = an animated noise blob so the trace is testable with no device (the default). 'existing_top' = trace a TOP you already have (existing_top_path). | synthetic |
| pre_blur | No | Gaussian blur (pixels) before thresholding — smooths noisy edges into clean contours. Live 'Blur'. | |
| edge_only | No | Run an Edge TOP before tracing so only the blob's boundary band is traced (hollow outline). | |
| threshold | No | Luminance cutoff that separates blob (foreground) from background. Live 'Threshold'. | |
| background | No | Background colour behind the traced contour (RGB 0..1). | |
| line_color | No | Contour line colour (RGB 0..1). | |
| line_width | No | Contour line width for the wireframe material. | |
| resolution | No | Output resolution [width, height]. | |
| parent_path | No | Parent network where the blob-trace container is created (default '/project1'). | /project1 |
| expose_controls | No | When true (default), expose live Threshold, Blur, and LineWidth controls. | |
| movie_file_path | No | Path to a movie file to trace; used only when source='file'. | |
| existing_top_path | No | Path of an existing TOP to trace; used only when source='existing_top'. |