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From image to CAM without losing the idea
Kerfspan keeps creative interpretation and CNC constraints in one reversible workflow. Dark geometry is retained metal; light geometry is removed. Work from broad intent toward physical detail:
Prepare Import, inspect Tone, choose a style, and save promising Candidates. Panel Set the real sheet, place the artwork, and confirm the cutting profile. Support Connect islands and stabilize long features without hiding important detail. Validate Locate blockers, preview reversible repairs, and finish manual corrections. Export Review scale and responsibility, then hand SVG/DXF to CAM.
What Kerfspan can promise It checks measurable geometry against your selected profile. “Ready for CAM review” does not certify material strength, machine setup, heat behavior, cut order, fixturing, or installation safety.
Read the canvas
Original Imported source and composition.
Tone The light/midtone/shadow field used by photo styles.
Artwork Generated creative treatment.
Material Retained metal and cut-outs—the main edit view.
Back-lit Visual reading of illuminated openings.
Problems Located validation findings and repair previews.
Step 1 · Prepare
Build the visual language first
Import PNG, JPEG, or WebP. Convert HEIC/HEIF first. Line art is thresholded locally; photographic styles use Kerfspan’s private analysis service. Inspect Tone before compensating with manual edits.
Image interpretation
Brightness and contrast set the overall range. Shadow detail controls dark information, surface smoothing suppresses texture, and tone separation strengthens light/midtone/shadow groups. The percentages describe the interpreted source, not final material coverage.
Choose a style by intent
Prepared Line art Clean drawings and logos.
Bold portrait Poster, Icon, Graphic, Silhouette Grouped shapes and strong recognition.
Engraved Linework, Woodcut, Flow, Contours Marks or ribbons that express light and form.
Geometric Slats, Hatch, Radial, Dots A regular system carries the image.
Decorative Ornamental symmetry Mirrored extracted linework.
Style guidance translates the current sheet and profile into a starting pitch, width, or diameter. Any mandatory clamp is explained beside the affected control. It is a starting point, not machine verification.
Candidates
Save visually meaningful alternatives before large changes. Candidates sync inside the project and restore the creative treatment. They differ from project Recovery points, which protect the broader editing workflow.
Good loop: Tone → style → recommendation → one deliberate adjustment → save Candidate → compare in Material and Back-lit.
Step 2 · Panel
Turn the composition into physical intent
Set real dimensions and orientation before judging pattern sizes. Position, scale, and freely rotate the artwork without stretching it. Arrow keys move it 1 mm; Shift+Arrow moves it 10 mm. Unused letterbox area remains retained metal.
Cutting-profile language
Kerf / tool diameter Expected removed path width, used for feasibility checks.
Minimum finished web Metal that must remain between neighboring cuts after machining.
Minimum opening Smallest removable feature the process should produce.
Provisional A useful starting profile without recorded machine evidence.
Verified Material, thickness, machine, source, evidence, verifier, and date are recorded.
The General plasma starting point uses a conservative 3 mm finished web and 2 mm opening. A 2 mm web can be explored, but must be confirmed for the actual process. Each project and retained export carries its exact profile snapshot.
Finished-edge workflow Kerfspan exports intended finished-part edges. Apply inside/outside kerf compensation exactly once in CAM. The profile kerf value supports checking; it is not permission to compensate twice.
Frame, anchors, and construction
The frame is retained material around the artwork. Anchor edges identify allowed structural attachment. In One-piece panel construction, all retained regions must connect to the main panel or selected anchors.
Step 3 · Support
Connect the panel with the least visual cost
Suggest smart supports creates a dashed proposal. Review it before accepting. Protect important detail avoids central/high-contrast features; Follow features prefers hair, brows, folds, shadows, and other darker structures. Filter direction aligns ties to Slats, Hatch, or Radial cuts, while long-slat stabilization controls unsupported span.
If no feature-aligned safe position exists, Kerfspan may offer a visible fallback or place nothing. Add a manual support instead of forcing an unsafe or destructive suggestion.
Manual support controls
Drag or tap start/end to create a support.
Drag the centre to move it; drag either endpoint for free angle and length.
Use numeric centre, angle, length, and width for exact work.
Arrow/Shift+Arrow moves 1/10 mm; P/N selects adjacent supports.
Delete/Backspace removes; Escape clears selection or an unfinished support.
Add, Remove, Restore, and Edit
Add retains metal; Remove creates a cut-out; Restore reveals the generated artwork beneath earlier manual work. Every new gesture remains an ordered, physical-unit operation instead of being baked into one bitmap. Choose freehand, straight, or connected-region behavior in Tool settings. Freehand smoothing steadies the path, Shift constrains a stroke to 15° increments, and a stroke can begin outside the sheet when its physical brush overlaps it.
Choose Edit and select an operation on the canvas or in the Manual edits list. Strokes can be moved, resized, hidden, changed between Add/Remove/Restore, or deleted without rewinding later work. Region edits can be hidden, changed, or deleted. One committed gesture or edit creates one Undo step; Pan never changes geometry.
Attachment rule: make endpoints overlap retained material enough to survive the selected kerf and process, then validate the combined result.
Step 4 · Validate
Use checks as a review queue, not a verdict
Run all checks on the current combined geometry. Blocking errors prevent SVG/DXF export. Structural warnings are advisory and may deserve strengthening or operator review. Select a row or Locate, use Next to cycle occurrences, and press Escape to clear the highlight.
What common findings mean
Disconnected retained piece: connect it or remove it in a one-piece panel.Opening too small: enlarge the removed region or close it.Cuts too close: add metal locally, move a cut, or revise the pattern.Thin outside a full-width core: inspect a bottleneck relying on undersized metal.Long unsupported span: add a stabilizer or revise the span assumption.
Automatic repair
Repairs are a previewable, reversible layer. Choose categories, build the preview, inspect it at useful zoom, then accept or discard. The planner protects long slat cuts from destructive whole-cut closure and can add small local amounts of metal when that meets the configured web.
Every attempt leaves an actionable report—even when no safe change was kept. Review physical area changed, finished connectivity, full-width-core survival, raster sampling uncertainty, the exact profile/model contract, why planning stopped, and the suggested next action. Planner diagnostics contain geometry counts and rejection reasons, never the photograph.
Manual corrections after accepted repairs override only conflicting generated cells; unaffected repairs remain. Re-running checks evaluates the combined geometry and does not delete accepted repairs. Changing artwork, placement, panel geometry, polarity, or profile can make them stale and require regeneration.
Step 5 · Export
Hand off a traceable result
PNG is available when geometry exists and is watermarked if validation is missing, stale, or blocking.SVG/DXF require current validation with zero blockers and preserve true panel scale in the chosen units.Variable Dots preserve circle primitives in vector export when possible.
Optional vector simplification reduces polyline nodes within a physical deviation limit. Kerfspan checks deviation, intersections, nesting, topology, and a rasterized manufacturing result; any regression automatically falls back to the exact raster trace.
The status bar and Export stage report the real X/Y millimetres per raster cell. Coordinate decimals do not create finer source geometry.
Every newly retained export carries a tamper-evident release manifest with exact geometry/file hashes, profile, units, compensation contract, processing versions, and validation findings. It follows encrypted sync and sharing.
Names include project, panel, style, frame, purpose, and timestamp.
Portable project downloads omit the original photograph; a successfully synced server project retains it.
CAM review checklist
Confirm units, sheet size/orientation, material polarity, frame, profile evidence, scale, duplicate contours, lead-ins, cut order, heat strategy, fixturing, and exactly one CAM kerf-compensation step. Test a new setup on a coupon or lower-risk part.
No automatic release claim Zero geometry blockers means Ready for CAM review. Machine and operator responsibilities remain.
Raster precision is not machine tolerance. Ordinary contours follow the displayed physical cell grid. The release manifest identifies exactly what was exported, but the target CAM and a suitable test cut still determine production acceptance.
Projects & recovery
Know where the latest work lives
Projects are complete encrypted server bundles with a browser-side offline cache and durable upload queue. The library opens its local cache immediately and refreshes the server in the background, so slow networking does not block navigation. Cards expose artwork preview, size, style, validation state, and source availability. Rename, duplicate, download, share, or move to recoverable Trash.
Saving… A local or server write is in progress.
Saved to server The server acknowledged this revision.
Waiting / Offline Cached on this device and queued.
Sync failed Tap Sync; queued work still needs attention.
Local cache failed Stop before closing—the latest edit may not be safely cached.
Ctrl/Cmd+S asks for an immediate save. Up to ten Recovery points follow significant validation, repair, support, and export events. Concurrent edits become conflict copies rather than silently overwriting work; compare them, rename the keeper, and Trash the duplicate.
Devices & sharing
Same workspace or independent copy?
Link your own devices
Open Projects → Devices on a linked device. Name the new device, create a one-time invitation, then scan its QR code or send its private link. The receiving browser joins the same workspace. Confirm Saved to server before changing devices and Sync on arrival.
An invitation expires, can be cancelled before use, and can be claimed once. A browser already linked elsewhere must explicitly confirm replacement. The current device cannot revoke itself accidentally; another linked device can disconnect a lost device.
Share a project
Share creates an encrypted snapshot for one recipient. The imported project is an independent editable copy—including available source, candidates, supports, repairs, recovery points, and retained exports. Later edits do not synchronize between the copies.
Do not clear site data to “log out” until every pending edit is synced or downloaded. Clearing it removes the offline cache and upload queue. To move the browser to another workspace, open that workspace’s invitation and confirm replacement.
Mobile & keyboard
Keep the canvas in reach
On narrow screens the canvas stays fixed. Tap a numbered stage to open controls as a bottom sheet, close it to inspect the result, and use Candidates/Problems for review. The bottom rail scrolls horizontally and retains Projects, Sync, Undo/Redo, and tools.
Install the app
On Windows, open Kerfspan in Edge or Chrome and choose the install icon in the address bar (or the browser’s Apps / Install menu). On Android, choose Install app or Add to Home screen. On iPhone/iPad, open Kerfspan in Safari, use Share, then Add to Home Screen. Open the installed app online once after an update so its PWA files and workspace state can refresh.
Keyboard reference
Keys Action
Ctrl/Cmd +S Save/sync now Ctrl/Cmd +Z Undo when canvas owns focus Ctrl/Cmd +Y Redo (also Shift+Z) F , + , − , 0 Fit, zoom in/out, reset I , K , R , B Icon style, Add, Remove, Support P / N Previous / next support Arrows / Shift +Arrows Move support or artwork 1 / 10 mm Delete Delete selected support Esc Clear highlight/selection, cancel, or return to Pan
Text fields retain their native undo. Workflow/review/project tabs support Left/Right, Home, and End. Browser pinch zoom is available in Pan; editing modes reserve one primary pointer for the active gesture.
Privacy & safety
Understand the boundary of the system
Complete project and share bundles are encrypted at rest on the server.
Photographic styles send the source to Kerfspan’s private analysis service.
Linked browsers use a secure HttpOnly device credential and retain an offline project cache.
Device/share secrets use the URL fragment rather than an ordinary request path or query.
Revocation blocks future server access but cannot remotely erase data already cached on an offline device.
Protect the operating-system account, use HTTPS, send invitations privately, revoke lost devices from another linked device, and avoid shared browser profiles for sensitive artwork.
Operator responsibility Kerfspan does not model stock defects, mechanical loading, consumable condition, gas/air quality, thermal distortion, lead-ins, sequencing, fixturing, or safe machine operation. Verify those in CAM and at the machine.
Troubleshooting
Recover without losing work
Sync spins or turns red Stay online, tap Sync, and watch the pending count. A failed older project can keep the global status red even when the current project synced. Look for conflict copies. Do not clear site data first.
A project is missing on another device Confirm both appear under Projects → Devices, the source says Saved to server, and the destination completed Sync. Share creates a separate copy; it does not link workspaces.
Tone controls are missing Select Tone. Prepare should reveal Image interpretation; expand Adjust tone if collapsed.
Repair layer needs regeneration An upstream dependency changed. Rebuild the preview against the current artwork, placement, panel, polarity, and profile.
SVG/DXF is disabled Generate geometry, run all checks, and resolve every blocker. PNG remains available and is watermarked while unvalidated.
The canvas is lost Select Pan and press F or Fit. This reframes the complete panel.
Smart supports find no safe placement Add a manual tie in a dark feature, widen attachment material, or revise the pattern. Only lower profile limits when the real setup supports them.
Processing performance
Measure this device without exposing artwork
Kerfspan records the latest elapsed times for rendering, geometry checks, repair planning, smart supports, and saving in this browser. Only task names, durations, outcome, device layout, and timestamps are stored—never image pixels or geometry.
No measurements yet Run a render, check, repair, support plan, or save on this device.
Clear timing history
Validation, repair planning, and smart-support graph work run outside the interface thread. Cancel stops that Worker immediately; a superseded or stale result cannot replace newer work. The last accepted geometry stays visible until a new result is accepted.
When reporting a slow operation: include the task name and elapsed time shown here, the device/browser, panel dimensions, and approximate artwork complexity. Do not send the source image unless you intend to share it.
No handbook topic matches that search.
Try a shorter term such as “sync”, “slats”, “kerf”, or “export”.