3D Scan Reverse Engineering

Make the destination component active, or right-click a component in the Browser, then choose Import Scan Reference…. Select an STL, OBJ, or meshed PLY file. STL and OBJ do not provide a trustworthy unit contract, and scanner exports vary in axis convention, so confirm the source units and the up axis before continuing.

The review shows the full-resolution vertex and triangle counts, bounds, coordinate conversion, available normals/colors/UVs, linked OBJ resources, and import diagnostics. Nothing enters the model until you accept that review. A point-only PLY is not a triangle mesh and cannot be used as a scan reference.

The original file and the required display data are retained inside the .jc3 by content hash. Save As or copying the project to another computer does not require the scanner folder or a sidecar cache. Older projects build the improved display data automatically from the scan already stored in the project; you do not need to reimport it.

To work through Agent Tower, open Project Files and import the STL, OBJ, or PLY first. Select an OBJ together with its MTL and texture files so the full set travels with the project. Tower identifies the archive entry from the open project and streams it into the same import path; you do not need to find a document ID or expose a computer file path to the agent. Large scan files use dedicated paged project storage, while the normal attachment limits for PDFs, images, and other project files remain unchanged.

To remove a placed reference, right-click it in the Browser and choose Delete. Undo restores it together with its dependent measurements and datums. Native sketches and features remain in the model, and the original scan evidence stays in the project.

Orbit, pan and zoom use the normal Drafting controls. Dense scans use complete connected surface levels, so moving or zooming never replaces part of the model with scattered triangles. Hover highlighting pauses during a camera gesture and refreshes when you stop. Display detail sharpens as you move closer and after motion settles.

Choose Scan display quality in Drafting view settings. Automatic favors responsive motion and sharpens after a short pause. High quality keeps the tighter target during motion and at rest for close inspection and video. Both choices use the same fixed memory limits and keep complete coverage; if a tighter level will not fit, JetCad3 quietly retains the complete coarser surface. This is normal display adaptation and does not produce an error.

Hidden references, references under a hidden parent, references outside isolation, and inactive Drafting workspaces release their display resources while retaining their placement and authored eye state. Showing or reactivating one restores a complete surface before sharpening it. In a complex assembly, superseded detail requests are coalesced and the current complete surface stays usable through a replacement. If a reference cannot display even its coarsest complete surface, a notice identifies that reference; ordinary changes in display detail remain quiet.

Display quality never changes the retained scan, fitted evidence, measurements, or native model. Committed picks resolve against the exact full-resolution source even when the visible surface is a coarser level. Existing projects gain these improvements when reopened and do not need reimporting. Hide reference, Disable Selection, and Lock remain available in the reference's right-click menu.

Named regions let you isolate the evidence needed for a bore, mounting face, casting surface, or clearance check. Regions can come from brush and lasso selection, a seed on connected geometry, islands, boxes, spheres, cylinders, or a captured screen polygon. Add, subtract, intersect, and replace refine the selection without exposing millions of triangle IDs.

Use Inspect Health to find disconnected islands, open boundaries, non-manifold edges, degenerate triangles, inconsistent normals, duplicate or opposed facets, ambiguous geometric welds, and nearby thin-wall risks. Scanner STL files often repeat the same coordinate for every facet; JetCad3 derives geometric adjacency for analysis while preserving the original facets and source triangle identity. Preparation can crop or mask a region, remove islands or outliers, repair normals, fill controlled boundary holes, smooth protected surfaces, and decimate at a selected tolerance.

Preparation is reversible. Every accepted operation creates a new variant, and the Browser can switch which variant supplies measurements. The original remains unchanged. JetCad3 identifies unchanged, altered, and inferred areas so a repaired hole is never mistaken for observed scanner data.

Right-click a reference or named region and choose Analyze Scan or Analyze Region. Geometry Summary calculates an area-weighted centroid, covariance, principal axes, normal clusters, and robust coordinate statistics. The X, Y, and Z radial presets calculate cylindrical profiles, distributions, radial envelopes, and periodic count and phase candidates around the selected document axis.

Each saved analysis appears under Scan Analyses. Its recipe, output types, assumptions, and engineering decisions remain inspectable after save and reopen. Periodic count and phase start as inferred candidates. You choose whether to accept them as current design intent; accepting scan evidence does not claim that the part follows a particular manufacturing standard.

Advanced Recipe… exposes the same bounded numerical graph used by Agent Tower and official MCP. Recipes can combine projections, filters, statistics, histograms, envelopes, correlation, table comparison, small equation solves, and bounded custom residual searches. Results use compact summaries and paged project-owned detail. Jobs report progress and can be cancelled. These operations are built into JetCad3, so an agent can perform them while shell access is disabled.

Agent feature proposals run as background jobs with progress and cancellation. A full search across all primitive types can take longer than a numerical summary. Select a named region and request only the relevant shape types when you already know what to look for. Cancelling a job releases its worker so queued analysis can continue. Scan processing runs in isolated background processes; completed analysis no longer hangs during shutdown or blocks project saves and queued jobs.

A named region can fit a line, plane, circle, arc, cylinder, cone, sphere, or torus. The preview reports the measured dimensions, observed coverage, conditioning, inliers and outliers, and RMS, percentile, and maximum evaluated residuals. A small patch that does not constrain a complete cylinder is reported as underconstrained instead of producing a confident-looking bore diameter.

Measured values, accepted nominal choices, scanner uncertainty, and manufacturing tolerance stay separate. A small fit residual describes how closely the selected mesh follows the fitted shape; it does not prove scanner accuracy.

Accepted fits can create reusable datums or align a placed reference. A 3-2-1 datum uses ordered plane evidence. Plane/axis/locator and fit-frame methods cover other mechanical setups. Separate, overlapping scans can be registered from paired landmarks or accepted datums and optionally refined as one rigid placement. Registration never stretches a scan or merges its source mesh.

Measurements include point and feature distance, diameter/radius, offsets, angles, center spacing, coaxiality, parallelism/perpendicularity, bolt-circle geometry, and relationships across components. Uniform scale calibration is explicit and records the measurement used; alignment never silently rescales a scan.

Create a single section or a spaced section stack from an arbitrary plane. JetCad3 keeps the raw triangle-intersection trace separate from the fitted result, so gaps and open ends remain visible.

A fitted section can become an ordinary sketch containing editable lines, arcs, and circles. Its endpoints, centers, axes, intersections, and applicable tangent points work with normal snapping, constraints, Extrude, Revolve, Hole, and export. Choose a raw sketch when retaining the measured polyline is more useful than fitted curves. Raw traces and fitted curves remain project resources through saving, reopening, and undo.

Mechanical reconstruction uses the same native history as a part modeled from scratch. A typical workflow is:

1. fit a mounting plane and bore cylinder;
2. create a datum from the accepted evidence;
3. extract one or more section sketches;
4. constrain the sketches and create normal Extrude, Revolve, Hole, Pattern, Boolean, Fillet, and Chamfer features; measured spline geometry can use editable involute parameters, root/tip bounds, pressure angle, phase, and tolerance-controlled curve approximation;
5. compare the finished bodies to the observed scan.

A feature can retain scan evidence for the values that informed it. Measured, accepted, and current native values remain visible separately. If you later edit the native dimension, JetCad3 marks that link as edited. Importing a newer scan or refitting a region produces a review of affected evidence and conflicts; it never silently rebuilds the model.

Irregular castings, molded shapes, and body panels can be decomposed into explicit patch regions. Fit editable surface controls at the selected tolerance, preserve sharp boundaries, and choose G0 or G1 continuity only where the observed geometry supports it.

The resulting surface patch is a normal editable Drafting history feature. Trim it with a scan region, accepted section, or sketch; stitch connected patches; then add thickness or close the shell when the geometry is valid. Missing areas are not bridged invisibly, a failed tolerance remains a diagnostic, and an open shell never becomes a solid merely because solid output was requested.

You do not need to reconstruct every object in a scan. Keep an axle, bracket, tube, body panel, or surrounding assembly as a reference in one component and create the new part in another active component. Use fitted axes, datums, sections, snaps, and persistent measurements to locate mounting features. Static clearance checks the new native body against the surfaces the scanner actually observed.

The scan remains reference geometry. It does not contribute stock, mass, cost, or manufacturing output unless you explicitly rebuild native bodies from it.

Compare to Native Model… evaluates full-resolution scan data against freshly evaluated native bodies. Current placement and datum-locked comparison preserve the model as drawn. A separately labeled best-fit diagnostic may calculate a rigid comparison transform, but it never moves the saved model. Reports include deviation statistics, tolerance, coverage, altered or inferred areas, and explicit numerical or sampling bounds. The maximum is the largest evaluated sample, not a certified continuous maximum. Preparation and analysis report progress, and cancellation reaches the running work. Inspection meshing uses curve tolerances appropriate for native curved bodies.

Inspect Static Clearance… checks scan-to-native or scan-to-scan pairs in their actual component placements. An open or incomplete scan can establish distance to observed surfaces, but it cannot prove that unseen space is empty.

Inspect Assembly Motion Clearance… follows explicit revolute, slider, or cylindrical joint coordinates, including coordinated motion. It solves detached poses and refines uncertain intervals, so the live assembly, viewport pose, saved drives, and undo history remain unchanged. The result reports the worst observed clearance and pose, continuous-path status, numerical bounds, and any unresolved intervals.

Inspection points are temporary. Close the result dialog to remove its points, or right-click a scan reference or saved inspection and choose Clear Scan Overlays. This removes the overlay without deleting your model, scan, or inspection report. Agent comparisons and clearance checks leave points hidden unless the agent explicitly requests a visual overlay.

Saved inspections export as Markdown, PDF, or JSON with selected units, source and variant hashes, frames, measured and nominal values, fit quality, coverage, error bounds, and optional Project Archive screenshots.

A scan reference has two dedicated mesh exports:

• Immutable Original… reproduces the retained source bytes and verifies their hash.
• Active Prepared Variant… writes the chosen derived variant as binary PLY with its identity, units, coordinate convention, and provenance.

STEP, STL, 3MF, and sketch DXF export still operate on native bodies and sketches. A scan reference is not presented as a reconstructed solid.

The manual tools, built-in Agent Tower, and official external MCP share the same scan services, analysis, component ownership, undo, jobs, cancellation, and revision checks. Agents discover references from the current project; you should not be asked to find a document, component, region, or feature ID.

Tower reads scan inputs from Project Archive and writes reports or mesh exports back as project artifacts. Large meshes and coordinate arrays never enter the conversation. You can ask an agent to inspect mesh health, isolate and fit a bore, create a datum, extract sections, build native history, fit editable surfaces, compare the result, or run a defined-motion clearance study.

This workflow does not control a scanner, import raw point clouds or proprietary scanner projects, sculpt arbitrary meshes, invent hidden features, apply nonrigid deformation, perform structural or dynamic simulation, search every possible assembly degree of freedom, create new CAM strategies, or operate connected machinery.

The recorded 32 GiB Apple Silicon qualification covers a 30-million-triangle individual scan and about 100 million triangles across four scans. Actual responsiveness depends on the source, storage, analyses, and visible detail. Windows and Linux capacity qualification is still pending.