Troubleshooting
No points appear in Live mode — work down this list:
- Press Test Sensor. It prints the sensor's identity, health, and available scan modes. No response means Houdini can't talk to the sensor.
- Check the port. Leave Port blank for auto-detect, or set it explicitly (e.g.
COM3). - Check the motor lead. The 5V cable must be plugged in — the motor won't spin on data power alone.
- Give it a moment. The motor takes about two seconds to spin up on the first cook.
- Lots of gaps is normal. On an open desk, most returns are invalid (nothing in range). Point the sensor at a wall to see a dense arc.
The sensor won't connect at all — no Windows chime and nothing new in Device Manager means a cable or port problem, not a driver problem: try a different USB port and swap the data cable — a faulty data cable stops the device enumerating entirely. If it enumerates but stays silent, check the adapter's baud switch is set to 256000.
"Port is in use" / permission errors — a serial port can only be opened by one program. Close anything else that might hold it:
- Another Houdini session in Live mode → set its Mode → Off.
- A separate tester/serial app → close it.
- A crashed process → the motor may keep spinning; unplug the 5V lead or restart to release the port.
Guides ended up in my simulation — you fed the solver from Output 0 (Points & Guides). Switch to Output 1 (Points), which strips the rplidar_viz guide geometry. Or turn off the Visualize guides, or delete the rplidar_viz group downstream. See Outputs and Attributes.
Tracking locks onto furniture instead of the hand — almost always the missing background bake. A real room clusters into 7–11 blobs per scan, and the largest is usually a chair or a wall corner — Single mode is picking the biggest thing present. Go Live, clear the interaction area completely, press Bake Background, then turn on Subtract Background. If it still wanders, tighten Blob Size min/max (a hand is roughly 0.05–0.15 m). See Background subtraction.
Tracking sees nothing at all after a background bake — you most likely baked while standing in the interaction area, so you were recorded as part of the static scene. Step out and bake again. Re-bake whenever the sensor moves or the room is rearranged. If it's an object hugging a wall that disappears, lower the Foreground Margin — a return has to be at least that much closer than the background to count as foreground.
Blob ids keep changing / a track keeps restarting — raise Hold Time so brief dropouts (a hand turning edge-on) don't end the track. Raise Max Speed if the motion is genuinely fast, and Min Points if the blob is breaking apart into specks at the edge of its range.
Playback shows nothing — confirm Mode = Playback and a valid file in Recording File (or leave it blank for the newest), and that Recording Directory points at where your .jsonl files live. Playback is driven by the playbar clock, so the timeline has to be playing or scrubbed.
Still stuck? Find me on the JVtools Discord — the invite link is in the Utilities folder on the HDA node.
