Create blob trace
create_blob_traceConvert a blob or silhouette from camera, movie, or synthetic source into clean vector line art in TouchDesigner by masking, thresholding, and tracing its contour, with adjustable 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'. |