PathBlender: Check FRC Auto Paths Together

Why I built PathBlender

Hi everyone, I’m Tony, the creator of PathBlender.

In the FIRST Robotics Competition (FRC), three teams work together as an alliance. Each team may have an autonomous routine that works on its own, but those routines can interfere with each other when all three robots share the field.

I built PathBlender to help teams compare those routines before a match. It puts routes from different teams on one field and one shared timeline, so you can see where robots might overlap and explore whether choosing another route or changing a start time would help.

PathBlender is free and open source.

Try it in your browser · Download the desktop app

If the project looks useful, I’d appreciate a Star on GitHub. You can also follow me for updates and future projects.

A quick demonstration

This 27-second video shows checking a potential collision, adjusting a robot’s start time, and replaying the routes:

What you can do

Import Choreo .traj, PathPlanner .path / .auto, and Collaborative PathPlanner .ghostauto files.

• Import Choreo .traj, PathPlanner .path / .auto, and Collaborative PathPlanner .ghostauto files.

Play multiple robots together, pause, and scrub through a shared timeline.

• Play multiple robots together, pause, and scrub through a shared timeline.

Adjust start times to compare different combinations.

• Adjust start times to compare different combinations.

Inspect potential robot overlaps and field-boundary violations.

• Inspect potential robot overlaps and field-boundary violations.

Switch between 2D and 3D views.

• Switch between 2D and 3D views.

Save sessions and export GIF replays or solution packages with the desktop app.

• Save sessions and export GIF replays or solution packages with the desktop app.

Teams can keep using their existing path-planning tools and bring the exported routes into PathBlender for comparison.

Try your first path check

You can try the workflow without installing anything or sharing team files:

Open PathBlender in your browser.

• Open PathBlender in your browser.

Select “Try your first path check” on the welcome screen.

• Select “Try your first path check” on the welcome screen.

Play the three synthetic practice routes together.

• Play the three synthetic practice routes together.

Select a reported conflict to inspect that moment.

• Select a reported conflict to inspect that moment.

Adjust a start time and replay the routes to compare the result.

• Adjust a start time and replay the routes to compare the result.

The practice routes are synthetic examples, not recordings from a real match.

Use it with alliance partners

Ask each team for the relevant path or auto files from its robot project. You don’t need the team’s entire codebase. For a PathPlanner .auto, include the referenced .path files in the same import.

A USB drive is a straightforward way to exchange files at an event. If internet is available, a shared link or attachment also works.

Import the routes, compare them on the shared timeline, and discuss which routines and start times work together. Apply agreed changes in the team’s planning tool or robot code, then test them on the robot.

This longer walkthrough shows configuring two teams’ routines and checking them together:

Browser or desktop

The browser version is the quickest way to try PathBlender.

For use at competitions, download the macOS, Windows, or Linux desktop app beforehand so you can work without relying on venue internet. Desktop also includes session saving and export features for sharing your comparison with alliance partners.

No account is required. Path files are processed locally and are not uploaded to a server.

What the checks can tell you

PathBlender is a planning aid. Its results depend on the imported paths, timing, and robot dimensions.

PathPlanner trajectories are regenerated locally, so their timing may differ from actual robot execution. Code-driven actions can also affect timing in ways the imported paths do not fully describe.

A clear timeline does not guarantee that the robots will avoid collisions on the field. Use the comparison to guide your discussion, then validate changes on the robot.

Feedback and source code

I’d like to hear how your team currently compares autonomous routines with alliance partners, and what would make this workflow more useful.

Please report import problems, confusing controls, or other suggestions through GitHub Issues. You don’t need to publish private path files to describe a problem.

View the source code and give PathBlender a Star · Follow me on GitHub

PathBlender’s own code is licensed under Apache-2.0. Third-party assets and components have separate terms; see the repository’s NOTICE for attribution and details.

This post was drafted with AI assistance.

FIRST®, FIRST® Robotics Competition, and FIRST® Tech Challenge are registered trademarks of FIRST® (www.firstinspires.org), which is not overseeing, involved with, or responsible for this activity, product, or service.