Fillet Guide
Get Started

Getting started with Fillet

Fillet is CAD for the parts you 3D print. In five steps you'll draw a plate, round its corners, drill two screw holes and send it to your slicer.

Know the editor

This is the plate you’re about to make, finished. Every design uses the same seven areas, and the other guides call them by these names.

The Fillet editor with the finished mounting plate: tool strip along the top, browser on the left listing Body 1, Sketch 1 and the clearance parameter, the plate with rounded corners and two screw holes on the print bed, the view cube top right, Print check on the right, and four steps on the timeline
  1. ToolbarUndo, redo, printer, Export and agents.
  2. Tool stripEvery modelling tool, grouped by job.
  3. BrowserBodies, sketches and parameters.
  4. ViewportYour part, on your printer's bed.
  5. View cubeStandard views, Fit all and visual styles.
  6. InspectorSettings for what you're doing or have picked.
  7. TimelineEvery step, in order. Tap one to change it.

Two colours tell you what’s going on. Orange is the step you’re working on. Blue is what you’ve picked.

Sketch the outline

Every part starts as a flat drawing. Here it’s an 80 × 30 mm rectangle on the bed.

  1. Open Fillet and tap New Design.
  2. Tap Sketch in the tool strip, then tap XY (the bed) in the bar that appears. The view turns to look straight down.
  3. Tap Rectangle in the sketch bar and drag from corner to corner with Apple Pencil.
  4. Tap Select (the arrow), tap the rectangle, and type 80 in Width and 30 in Height.
  5. Tap Finish sketch.

In landscape, Start a sketch on the bed in the inspector does step 2 in one tap.

No Pencil? Tap the hand button in the sketch bar, just left of Finish sketch (in portrait it’s the bar’s last button). Your finger then draws instead of turning the view.

The sketch inspector for Sketch 1 with the rectangle selected: Rectangle set to Corner, Width 80 mm and Height 30 mm
Draw roughly, then type the real sizes.

Make it solid

Extrude pushes the sketch up into a plate.

  1. Tap Extrude. The rectangle is the only shape, so it’s picked for you.
  2. Type 6 in Distance, or drag the orange arrow on the part.
  3. Tap Done.
The Extrude 1 inspector: 1 profile picked, Operation New, Distance 6 mm
The arrow and Distance set the same thing.

Round the corners

Fillet rounds edges. Round the four upright corners so the plate has no sharp points.

  1. Tap Fillet.
  2. Tap each of the four upright corner edges. For the one at the back, drag with one finger to turn the view first.
  3. Type 5 in Radius.
  4. Tap Done.

The part shows the round as you type, so you see it before you tap Done.

The Fillet 1 inspector: 4 edges picked in 4 tangent chains, Tangent chain on, Radius 5 mm
Each tap adds one edge to the count.

Drill the screw holes

Hole drills holes that fit a real screw. Pick the screw, and Fillet fills in the sizes.

  1. Tap Hole.
  2. Tap the top of the plate near each end. The first tap picks the face, and each tap adds a hole.
  3. Tap Preset and choose Socket head counterbore › M3.
  4. Under Extent, tap Through all.
  5. Tap Done.
The Hole 1 inspector: 2 holes picked, Preset M3 socket head counterbore, and a hint that it adds the clearance parameter of 0.2 mm
Screw holes get 0.2 mm of clearance.

If your screws bind once printed, raise clearance under Parameters in the browser, and every hole follows. Tune the fit for your printer →

Send it to your slicer

With nothing selected, the inspector shows Print check. Three green ticks mean the part is ready to print.

  1. Check that Print check says Fits the bed, No overhangs and Watertight.
  2. Tap Export in the toolbar and choose 3MF.
  3. Save the file to Files, then open it in Bambu Studio, PrusaSlicer or your slicer of choice.

That’s a printable part, about 17 g of PLA. Every step stays on the timeline: tap Fillet 1 there, type a new radius and tap Done, and the steps after it update.

The Export menu open over the inspector with 3MF (Bambu Studio, PrusaSlicer…), STL and STEP (other CAD apps). Under it, Print check shows Fits the bed 80 × 30 × 6 mm, No overhangs and Watertight, and Material 17.36 g of PLA
Export sits at the top right. 3MF opens in most slicers.
Change your design with the timelineEdit, reorder, suppress or roll back any step.Check a part and export it for printingPick a printer, check the part and send it to your slicer.

Questions and answers

How do I move around the model?
Drag with one finger to turn it, drag with two fingers to slide it, and pinch to zoom. Double-tap with two fingers to fit everything in view. With Apple Pencil, you draw and pick, and your fingers keep moving the view. On a keyboard’s trackpad, scroll with two fingers to slide and pinch to zoom.
Why is a tool grey?
It can’t run yet. Tap it anyway and Fillet says why. In an empty design, Fillet says Needs a body. Extrude a sketch first.
How do I change how the part looks?
Use the buttons under the view cube. Tap a face of the cube for a straight-on view, tap Fit all to frame the part, and use the chip under them to pick one of six styles, from Shaded to Hidden line. They change the view, never the design.
Do I need an account?
No. Fillet works offline, never asks you to sign in and never needs a network.
Where are my designs?
Wherever you save them: On My iPad, iCloud Drive or any Files location. Each design is one .fillet file. Files, iCloud and importing STEP →
What changes in portrait or Split View?
The panels make room for the part. The browser floats over it: tap Browser in the tool strip to show it. The inspector appears once you start a step or pick something, and in the narrowest windows it’s a drawer under the view that you drag taller or shorter. An empty design has no Start a sketch on the bed button there, so tap Sketch, then XY.
Does it work the same on a Mac?
Yes. Click where this guide says tap, and drag to turn the view. On a trackpad, scroll with two fingers to slide the view, and pinch or hold ⌘Cmd while you scroll to zoom. With a mouse, the scroll wheel zooms and Shift-right-drag slides. Press ⌘Cmd0 to fit everything in view.
Sketch a profileRound, bevel and hollow: Fillet, Chamfer and ShellDrill holes for screwsCheck a part and export it for printing

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