changed the docker.py

Dockerfile

@@ -11,6 +11,9 @@ ENV LD_LIBRARY_PATH=${CUDA_HOME}/lib64:${LD_LIBRARY_PATH}
 # Fix OpenMP threads to a valid integer (libgomp warning)
 ENV OMP_NUM_THREADS=4
 
+# Force headless: never try X11 DISPLAY
+ENV DISPLAY=""
+
 # ---------------- System deps + Python 3.12 + headless GL ----------------
 RUN apt-get update && apt-get install -y --no-install-recommends \
     software-properties-common \

app.py

@@ -12,6 +12,19 @@ import numpy as np
 import torch
 import pyvista as pv
 
+os.environ.setdefault("OMP_NUM_THREADS", "4")
+
+# Optional: extra VTK headless hints (you already used similar locally)
+os.environ.setdefault("VTK_DEFAULT_RENDER_WINDOW_OFFSCREEN", "1")
+os.environ.setdefault("LIBGL_ALWAYS_SOFTWARE", "1")
+os.environ.setdefault("MESA_LOADER_DRIVER_OVERRIDE", "llvmpipe")
+os.environ.setdefault("MESA_GL_VERSION_OVERRIDE", "3.3")
+
+# Force headless: never try to open an X11 window
+os.environ["DISPLAY"] = ""
+
+pv.OFF_SCREEN = True  # Tell PyVista to always render offscreen
+
 from scipy.spatial import cKDTree
 from vtk.util import numpy_support as nps
 import matplotlib.cm as cm