Fillet Guide
Select & Change

Use parameters and expressions

Give a size a name, such as wall = 2, and type that name wherever a number goes. Change the value once, and every step that uses it follows.

Name a value

Parameters live at the bottom of the browser, the sidebar on the left. If it’s hidden, tap Browser at the left end of the tool strip.

  1. Under Parameters, tap Add parameter. A card appears, named p1 and set to 10 mm.
  2. Tap p1, type a name such as wall, and press Return.
  3. Tap the field after = and type the value, such as 2.
The Parameters list with one new card, p1 = 10 mm, and Add parameter under it.The same card renamed: wall = 2 mm.
Add parameter makes p1. Give it a name and a value.

A name uses letters, digits and _, and can’t be a unit or function such as in or sin. If Fillet can’t use a name, it says why under the card and keeps the old one.

Use it in any field

Type the name wherever a number goes, and mix in sums and units: height - wall, width / 3, 1 in + wall.

  1. Open a step: tap its station on the timeline, or start a new one.
  2. Tap a field and type an expression with the name, such as height - wall.
  3. Tap Done.

The field keeps what you typed and shows what it comes to underneath.

Two parameter cards: height = 40 mm and wall = 2 mm.The Holes step in the inspector. Distance reads height - wall, with = 38 mm under it.
In this pen holder, height is 40 and wall is 2, so the holes are cut 38 mm deep.

Every number field takes maths, with or without parameters, including a sketch’s Width and a hole’s X and Y.

Expression referenceEvery unit and function you can type, and what each red message means.

Change it once

Change a parameter’s value, and every step that uses it rebuilds. In the pen holder, set hole_d to 16 for fatter markers. The holes grow, and the block grows 2 mm around them to keep its walls. Nothing else needs touching.

If a step turns red

A step remembers each profile by the spot you tapped. If a change moves a profile away from that spot, the step turns red on the timeline. Set width to 120, and the outer holes slide away: Holes failed: A selected profile no longer exists — reselect it.

The timeline: Base, Block, Pen holes, and Holes in red with a red dot.
The step that needs you turns red.
  1. Tap the red station.
  2. Tap Clear next to the profile count.
  3. Tap each profile again, then tap Done.
The Holes step: A selected profile no longer exists — reselect it, and 3 profiles picked with Clear.
Clear the old picks, then tap the profiles again.

Rename or delete a parameter

To rename a parameter, tap its name and type a new one. Fillet rewrites every expression that uses it, so nothing breaks.

To delete one, tap the trash button on its card. Steps that used it turn red, with a message such as Unknown parameter ‘hole_d’. Undo brings it back.

Expression referenceDrill holes for screwsChange your design with the timelineRepeat with patterns

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