Import format: open a design from a link

Any suspension design can be opened in opensus from a link. https://opensus.app/app/?example=fsae opens a built-in example; https://opensus.app/app/?design= followed by URL-encoded JSON opens your own hardpoints. This lets a forum post, a spreadsheet or an AI assistant hand someone a working geometry.

Opening a link never loses work: whatever design was already open is kept under Project → Saved first.

Examples

Link Opens
/app/?example=fsae Formula SAE car: pushrod double wishbones front and rear
/app/?example=sedan E30-style sedan: MacPherson front, semi-trailing arm rear

Design JSON

{
  "name": "My car",
  "example": "fsae",
  "front": {
    "type": "doubleWishbone",
    "camber": -1.5,
    "toe": 0.1,
    "points": {
      "ucaOuter": [-8, 550, 330],
      "lcaOuter": [3, 570, 125]
    }
  },
  "rear": {
    "type": "fiveLink",
    "points": { "tieInner": [-130, 215, 185] }
  }
}

Every field is optional:

Field Meaning
name Name shown in the header
example Start from an example (fsae or sedan) instead of the default car
front, rear One axle, given as its left corner and mirrored to the right
type doubleWishbone, macpherson, fiveLink or semiTrailing. Points not listed keep that type's defaults
camber, toe Static camber and toe-in in degrees at the loaded position
points Point name → [X, Y, Z] in mm, in opensus coordinates: ISO 8855, measured from the axle line, centreline and ground

Put the JSON in the design parameter, URL-encoded. In JavaScript: "https://opensus.app/app/?design=" + encodeURIComponent(JSON.stringify(design)). In Python: "https://opensus.app/app/?design=" + urllib.parse.quote(json.dumps(design)).

If part of a link can't be used, such as an unknown point name or a coordinate that isn't a number, opensus opens the rest and lists what it skipped.

Point names

These are the names to use in points, with each type's default front-corner position.

Double A-arm (doubleWishbone)

Name Point Default front position, mm
ucaFront Upper arm, front inner 110, 280, 292
ucaRear Upper arm, rear inner -110, 280, 288
ucaOuter Upper ball joint -8, 550, 330
lcaFront Lower arm, front inner 120, 200, 113
lcaRear Lower arm, rear inner -120, 200, 117
lcaOuter Lower ball joint 3, 570, 125
tieInner Tie rod inner -68, 215, 148
tieOuter Tie rod outer -70, 565, 165
wheelCentre Wheel centre 0, 604, 222
rodOuter Pushrod at lower arm 0, 530, 135
rodInner Pushrod at rocker 0, 260, 420
rockerPivot Rocker pivot 0, 220, 370
rockerAxis Rocker axis 40, 220, 370
springRocker Coilover at rocker 0, 170, 410
springChassis Coilover at chassis 0, 60, 300
arbPivot Sway bar pivot 70, 175, 300
arbAxis Sway bar axis 70, 115, 300
arbTip Sway bar arm tip -30, 175, 300
arbDrop Drop link at rocker -30, 175, 395

MacPherson strut (macpherson)

Name Point Default front position, mm
lcaFront Lower arm, front inner 130, 210, 118
lcaRear Lower arm, rear inner -130, 210, 122
lcaOuter Lower ball joint 5, 575, 120
strutTop Strut top mount -25, 500, 620
strutBase Strut base on upright -5, 545, 300
strutGuide Strut axis guide -10, 534, 380
tieInner Tie rod inner -110, 220, 190
tieOuter Tie rod outer -110, 560, 195
wheelCentre Wheel centre 0, 604, 222
Name Point Default front position, mm
upperFrontIn Upper front link inner 160, 260, 320
upperFrontOut Upper front link outer 30, 540, 335
upperRearIn Upper rear link inner -150, 270, 325
upperRearOut Upper rear link outer -35, 540, 335
lowerFrontIn Lower front link inner 170, 210, 125
lowerFrontOut Lower front link outer 40, 565, 118
lowerRearIn Lower rear link inner -170, 210, 125
lowerRearOut Lower rear link outer -40, 565, 118
tieInner Tie rod inner -130, 215, 180
tieOuter Tie rod outer -130, 560, 190
wheelCentre Wheel centre 0, 604, 222
springUpright Coilover at upright 0, 500, 175
springChassis Coilover at chassis 0, 400, 470

Semi-trailing arm (semiTrailing)

Name Point Default front position, mm
armInner Arm pivot, inboard 200, 170, 250
armOuter Arm pivot, outboard 295, 500, 250
wheelCentre Wheel centre 0, 604, 222
springArm Spring at arm 50, 400, 160
springChassis Spring at chassis 50, 400, 330
damperArm Damper at arm -50, 500, 190
damperChassis Damper at chassis -20, 470, 480

Project files

For a complete design (every point, link, spring, damper, tire and setting), use a project file instead: Download → opensus project saves a .opensus.json file, and Project → Upload project opens one. Project files use the same ISO 8855 millimetre coordinates.

Last updated 2026-11-07 · View as Markdown