Prepare the paths
CNC Vector File Maker and CNC Path Preparation weld the design and separate through-cuts, pockets and drills. Inside / Outside Path Offset applies the bit radius the right way for each contour.
CNC · 14 tools
CNC router file preparation
Inside and outside offsets, pockets, tabs, drill holes, path order, entry points and G-code generation for a router cutting the file you designed.
A CNC router cuts with a round bit, and everything about preparing a file follows from that. The bit has a diameter, so an outline must be offset outward for a part and inward for a hole or the part comes out one bit width wrong. The bit is round, so it cannot cut a sharp internal corner. The bit pushes, so a part cut free will move unless tabs hold it. And the bit enters somewhere, so each path needs a sensible start point.
These tools take a cutting file and produce a toolpath-ready version: the correct offsets for the bit diameter, pockets for engraved areas, tabs, drill holes at the right size, an entry point per path, an order that finishes inner features before outlines, and optionally the G-code itself, previewed before it goes anywhere near a machine.
Try it here
CNC Path Preparation
Weld, simplify and close paths for toolpaths.
How a cnc job runs
Hold the parts
CNC Tabs Generator leaves 6 to 10 mm tabs, 1 to 2 mm thick, on each part outline. Drill Hole Generator adds holes sized to the bit, and Pocket Shape Generator marks areas to clear rather than cut.
Order and enter
Path Ordering finishes pockets and holes before outlines and minimises rapid moves. Entry Point Generator places each start on a straight section, away from corners.
Generate and check
G-code Generator writes GRBL-style code with the feeds and depths you enter; G-code Viewer / Preview draws it so you see every move before the spindle starts. Export DXF for VCarve, Aspire or Fusion if you prefer to CAM there.
All cnc tools
14 tools · Inside/outside offsets, tabs, drill holes, path order and G-code.CNC Vector File MakerClean, offset and ordered DXF for CNC routers.CNC Path PreparationWeld, simplify and close paths for toolpaths.Toolpath PreviewPreview the tool centre-line for a bit diameter.Inside / Outside Path OffsetOffset outer profiles out and holes in by the tool radius.Pocket Shape GeneratorConcentric pocket clearing passes.CNC Tabs GeneratorHolding tabs on outer profiles.Drill Hole GeneratorDrill holes on a grid or at corners.CNC Cut Length CalculatorTotal toolpath length of a file.CNC Material LayoutArrange parts on the spoilboard sheet.CNC Sheet NestingNest parts for the router bed.Path OrderingInside-first ordering with minimal rapids.Entry Point GeneratorChoose where each cut starts.G-code GeneratorSimple 2.5D G-code from cutting paths (advanced).G-code Viewer / PreviewVisualise G0/G1 moves from a G-code file.
On the machine
Bit diameter and offsets
A 6 mm bit means a 3 mm offset outward on parts and inward on holes. Internal corners come out with a 3 mm radius; for square-cornered joints, add dog-bone or T-bone reliefs, which the offset tool can place at internal corners.
Tabs
Tabs hold a freed part against the bit's push. On 12 mm MDF, four tabs of 8 mm long by 1.5 mm thick per part; on 3 mm material, two tabs of 5 by 1 mm. Cut them off with a flush trim afterwards.
Depth passes
Cut depth per pass is usually the bit diameter or less in MDF and half of it in hardwood and acrylic. The G-code generator steps down automatically from the total depth and per-pass value you enter.
Climb versus conventional
Path direction sets the milling mode. Conventional (clockwise around outside contours with a right-hand bit) is safer on cheap machines; climb gives a cleaner edge on rigid ones. Path Direction Reverser in the vector group flips it.
What usually goes wrong
- Cutting on the line. Without an inside/outside offset every part is a bit width too small and every hole a bit width too big.
- No tabs on small parts. They spin, fly, and take the bit with them.
- Outlines before pockets. The part moves after it is freed and the pocket lands off-position.
- Plunging into a corner. Entry points on a straight section avoid the burn and the witness mark.
- Running generated G-code without a preview. The viewer takes seconds; a crashed spindle takes a day.
Common questions
Which controllers read the G-code?
The generator writes plain G0/G1 moves with feed rates, spindle on/off and safe-height retracts, which GRBL, Mach3, Mach4, LinuxCNC and most Chinese controller boards accept. Check the safe height and units line before running.
Are feeds and speeds calculated?
No. Feed rate, spindle speed and depth per pass depend on the machine, bit and material, and you enter them. The tool applies them consistently; it does not choose them.
Can I make a sign with raised letters and a pocketed background?
Yes: put the letters on the through-cut or leave-standing layer and the background on a pocket layer with Pocket Shape Generator. The path order clears the pocket first.
How do I quote a CNC job?
CNC Cut Length Calculator sums the toolpath length including passes; divide by the feed rate for cutting time and add rapid moves. The cost group turns that into a price with material and labour.