Pre-configured WPILib SimGUI window layouts for REBUILT 2026

The repo ships pre-configured WPILib Simulation GUI layouts in Simgui_layouts/. Each subfolder is a self-contained template: copy its simgui.json (and any image assets) to the project root before launching the simulator, and the GUI will load the layout automatically on startup.

Available layouts

Folder	Description
`Simgui_layouts/VisionSim/`	Visualizes ground-truth pose vs. vision-estimated pose and shows per-camera AprilTag detection wireframes on the Field2d widget

How to use a layout

Pick a layout subfolder

Browse the Simgui_layouts/ directory and choose the layout that matches what you want to test. For vision debugging, use Simgui_layouts/VisionSim/.

Copy files to the project root

Copy simgui.json and all image files from the chosen subfolder into the repository root (the same directory that contains build.gradle):

# From the repository root — copy the VisionSim layout
cp Simgui_layouts/VisionSim/simgui.json .
cp Simgui_layouts/VisionSim/*.png .

The VisionSim layout ships with three image assets used as icons on the Field2d widget:

File	Purpose
`swerve_module.png`	Icon for each of the four simulated swerve modules
`tag-blue.png`	Marker for AprilTags visible to the simulated cameras
`tag-green.png`	Marker for other AprilTag field positions

Run the simulator

Launch the simulator — the GUI reads simgui.json from the project root automatically:

./gradlew simulateJava

All widget positions, sizes, and data source paths defined in simgui.json are restored immediately when the GUI opens.

The root-level simgui.json is listed in .gitignore. Your local working copy will never be committed. The canonical, checked-in copies always live inside the Simgui_layouts/ subfolders — those are the templates you copy from. This means each developer can freely modify their local layout without affecting teammates.

VisionSim layout

The VisionSim layout is designed to let you verify the full PhotonVision → Limelight conversion pipeline at a glance. The Field2d widget is pre-wired to display:

Field2d object	What it shows
`EstimatedRobot`	Where the robot thinks it is (odometry + vision correction)
`EstimatedRobotModules`	The four swerve modules at their computed positions and steering angles
`GroundTruthRobot`	Where the robot actually is in the physics simulation
`Vision_limelight-a_MT1`	MegaTag1 pose estimate from camera A
`Vision_limelight-a_MT2`	MegaTag2 pose estimate from camera A
`Vision_limelight-b_MT1`	MegaTag1 pose estimate from camera B
`Vision_limelight-b_MT2`	MegaTag2 pose estimate from camera B
`Vision_limelight-c_MT1`	MegaTag1 pose estimate from camera C
`Vision_limelight-c_MT2`	MegaTag2 pose estimate from camera C

Vision estimate objects disappear from the field automatically when no AprilTags are visible to that camera (the object’s poses list is cleared). To stress-test vision correction, use the D-pad on the driver controller (active only in simulation):

POV-right — injects 0.5 m translation drift and ±15° heading drift into the pose estimator. The ground-truth pose does not change; watch the estimated pose jump away from the ground truth and then converge back as vision corrections arrive.
POV-left — cycles through four preset reset positions (auto start on correct alliance side, auto start on wrong alliance side, field origin on correct side, field origin on wrong side).

For more details on the full simulation architecture see Simulation Overview, and for the vision pipeline internals see Vision Sim.

Get Started

Subsystems

Autonomous

Simulation

Configuration & Tuning

Pre-configured WPILib SimGUI window layouts for REBUILT 2026

Available layouts

How to use a layout

VisionSim layout

​Available layouts

​How to use a layout

​VisionSim layout

Available layouts

How to use a layout

VisionSim layout