Motus.OMPL.NET 0.5.0

Motus.NET

Standalone .NET 8 robotics motion-planning library for the Motus toolkit. Planning, validation, and export only — no UI, no vendor runtime, and no connection to physical robots.

Motus.OMPL.NET is the OMPL adapter layer: it targets unified native motus_native (OMPL + optional FCL) via Motus.Native (see docs/ompl-port-plan.md). Until the native library is built, managed RRT-Connect and C# mesh collision (including attach) are used.

Arbitrary serial manipulators can be loaded from URDF (UrdfRobotLoader) or bundled JSON presets. FK/IK use DH profiles on bundled presets (analytic IK for Universal Robots) and numerical IK on generic URDF chains.

Licensed under MIT.

Rhino 8 / Grasshopper

Windows and macOS hosts use managed planning and collision by default — no Linux .so, no LD_LIBRARY_PATH. See docs/rhino-host.md.

Install

dotnet add package Motus.Core
dotnet add package Motus.Geometry
dotnet add package Motus.OMPL.NET
dotnet add package Motus.Native
dotnet add package Motus.OMPL.Native
dotnet add package Motus.Presets

Load a robot

// Bundled preset
var preset = PresetLoader.LoadByModelName("UR5e");

// URDF (revolute serial chain)
var robot = UrdfRobotLoader.Load("path/to/robot.urdf", new UrdfLoadOptions {
    BaseLink = "base_link",
    TipLink = "tool0"
});
var fk = KinematicsResolver.CreateFkSolver(robot.Preset, robot.Chain);

Planners

Motion Programs (0.5.0)

var planner = new IndustrialMotionPlanner(robot.Preset);
var request = new MotionProgramRequest(
    robot,
    start,
    new MotionSegment[]
    {
        new PtpSegment(ptpGoal, blendRadiusMeters: 0.004),
        new LinSegment(linGoal, stepMeters: 0.005, blendRadiusMeters: 0.003),
        new CircSegment(circVia, circGoal, arcSamples: 12)
    });

var result = planner.Plan(request);

• Segment model: PtpSegment, LinSegment, CircSegment
• Current blend behavior: deterministic fallback to exact-stop when a requested blend is not feasible/supported
• Export includes motion metadata (motionType, segmentIndex, blendRadiusMeters) for replay/debugging

Attach (pick-style)

var ctx = PlanningContext.Create(robot, scene)
    .Attach("workpiece", workpieceBox, tcpLocalFrame);
var checker = CollisionCheckerFactory.Create(robot, attached: ctx.Attached);
var result = new RrtConnectPlanner(checker).Plan(
    new PlanningRequest(robot, start, goal, ctx.ToPlanningOptions()));

MotusCapabilities.Describe() reports native OMPL/FCL availability for hosts.

Planning group (SRDF-style)

// From SRDF (official MoveIt config, pairs with unmodified URDF)
var groups = SrdfLoader.LoadGroups("robot.srdf");
var ctx = PlanningContext.Create(robot, scene).ForGroup(groups[0]);
var result = new RrtConnectPlanner(checker).Plan(
    new PlanningRequest(robot, start, goal, ctx.ToPlanningOptions()));

// Or manual joint list (partial-DOF lock)
var group = new PlanningGroup("arm", "base_link", "tool0",
    ["shoulder_pan", "shoulder_lift", "elbow", "wrist_1", "wrist_2"]);
var ctx2 = PlanningContext.Create(robot, scene).ForGroup(group);

Non-group joints stay locked at the start configuration during planning.

Native OMPL + FCL: optional on Linux when motus_native is built with OMPL/FCL. Win/Mac NuGet ships stubs — managed RRT and C# mesh collision run by default (see docs/rhino-host.md).

Units

Internal units are radians, seconds, and meters. Use Motus.Core.Units for degree/radian conversion.

0.5.0 Migration Notes

See CHANGELOG.md (Unreleased) for upgrade details.

Build & test

dotnet build Motus.NET.slnx
dotnet test Motus.NET.slnx

Native motus_native (optional):

cmake -S native -B native/build -DMOTUS_USE_OMPL=ON -DMOTUS_USE_FCL=ON
cmake --build native/build
# Linux: export LD_LIBRARY_PATH=native/build

Requires the .NET 9 SDK or newer to read the .slnx solution; the libraries target net8.0.

Releases

Push a version tag (v0.5.0) to run .github/workflows/release.yml: build, test, pack, publish to nuget.org via trusted publishing, and create a GitHub Release with .nupkg assets.

Configure the nuget.org trusted publisher policy (one-time):

1. nuget.org → Account → Trusted Publishing → Add
2. Provider: GitHub, owner lasaths, repository Motus.NET, workflow filename release.yml (exact match)
3. Re-run the failed Release workflow on the tag after the policy is saved (or push the next tag)

Safety

Motus does not send commands to physical robots. Robot presets and URDF imports are planning/visualization defaults — verify all limits and calibration before any hardware use. See docs/safety.md.

AI-assistance disclaimer

This library and its bundled robot presets were developed with AI assistance. All values are approximate and must be independently verified against official manufacturer datasheets and the real controller before any physical use.

Attribution

• Managed RRT-Connect fallback implements the RRT-Connect algorithm (Kuffner & LaValle, ICRA 2000). Native planning uses OMPL (BSD-3-Clause) when built.
• Robot presets are approximate values from public datasheets, for planning/visualization only.