Cannot connect to the worker
BLUX runs its solvers in a separate worker process and talks to it over a loopback connection on your machine. If Blender cannot reach that worker, you see:
Failed to connect to BLUX GPU simulation worker
This almost always means one of two things: Taichi is missing from the interpreter BLUX picked, or no supported GPU backend is available.
Step 1: run the environment check
Section titled “Step 1: run the environment check”- Open Edit > Preferences > Add-ons > Blux Physics Suite.
- Under Solver, click Check Solver Environment.
- Read the result.
| Result | Meaning | Fix |
|---|---|---|
| OK | The interpreter runs and Taichi imports. | Go to step 2. |
| Error, with Install it with: pip install taichi | The interpreter was found, but Taichi is not installed in it. | Run python -m pip install taichi==1.7.4 numpy in that interpreter. |
| A Found: row with Use It | A working interpreter exists elsewhere on your system. | Click Use It. |
| A red message under Interpreter | The path you entered is not valid. The message says why, and which interpreter is used instead. | Fix or clear the path. |
| Nothing is found | BLUX could not locate any Python. | Install Python 3.11 to 3.13 and set the Interpreter path. |
BLUX looks for the interpreter in this order: the Interpreter preference, BLUX_PYTHON_PATH, python or python3 on PATH, then common Windows install locations. The row under the button shows which one was picked.
Step 2: try the CPU backend
Section titled “Step 2: try the CPU backend”If the check is OK but the worker still fails to start, set Backend to CPU only and try again. CPU is slow, but if it works, the problem is the GPU driver or backend rather than the install. Then try Vulkan or CUDA explicitly, and update your GPU driver.
Step 3: restart the worker
Section titled “Step 3: restart the worker”If the worker is running but unresponsive, use Restart Worker in the Diagnostics panel. It ends the worker, cleans up leftover sockets and starts a new one.
Still stuck?
Section titled “Still stuck?”Note the exact message and the output of Check Solver Environment. Ask in the BLUX community on Discord, or send a message with the contact form. See Getting help for what to include.