diff --git a/src/c3nav/mapdata/render/engines/__init__.py b/src/c3nav/mapdata/render/engines/__init__.py
index 36070ee1..66e4e4ad 100644
--- a/src/c3nav/mapdata/render/engines/__init__.py
+++ b/src/c3nav/mapdata/render/engines/__init__.py
@@ -2,6 +2,7 @@ from django.conf import settings
 from django.core import checks
 
 from c3nav.mapdata.render.engines.svg import SVGEngine  # noqa
+from c3nav.mapdata.render.engines.stl import STLEngine  # noqa
 
 
 @checks.register()
diff --git a/src/c3nav/mapdata/render/engines/base3d.py b/src/c3nav/mapdata/render/engines/base3d.py
index 45a52b14..2511046d 100644
--- a/src/c3nav/mapdata/render/engines/base3d.py
+++ b/src/c3nav/mapdata/render/engines/base3d.py
@@ -16,6 +16,9 @@ class Base3DEngine(RenderEngine):
         self.np_scale = np.array((self.scale, self.scale, self.scale))
         self.np_offset = np.array((-self.minx * self.scale, -self.maxy * self.scale, 0))
 
+    def _add_geometry(self, geometry, fill: Optional[FillAttribs], stroke: Optional[StrokeAttribs], **kwargs):
+        if fill is not None:
+            self.vertices.append(self._place_geometry(geometry))
 
     def _append_to_vertices(self, vertices, append=None):
         if append is not None:
diff --git a/src/c3nav/mapdata/render/engines/stl.py b/src/c3nav/mapdata/render/engines/stl.py
new file mode 100644
index 00000000..6aab4841
--- /dev/null
+++ b/src/c3nav/mapdata/render/engines/stl.py
@@ -0,0 +1,24 @@
+import numpy as np
+
+from c3nav.mapdata.render.engines.base3d import Base3DEngine
+
+
+class STLEngine(Base3DEngine):
+    facet_template = (b'  facet normal %f %f %f\n'
+                      b'    outer loop\n'
+                      b'     vertex %f %f %f\n'
+                      b'      vertex %f %f %f\n'
+                      b'      vertex %f %f %f\n'
+                      b'    endloop\n'
+                      b'  endfacet')
+
+    def _create_facet(self, facet) -> bytes:
+        return self.facet_template % tuple(facet.flatten())
+
+    def render(self) -> bytes:
+        facets = np.vstack(self.vertices)
+        facets = np.hstack((np.cross(facets[:, 1]-facets[:, 0], facets[:, 2]-facets[:, 1]).reshape((-1, 1, 3))*1e10,
+                            facets))
+        return (b'solid c3nav_export\n' +
+                b'\n'.join((self._create_facet(facet) for facet in facets)) +
+                b'\nendsolid c3nav_export\n')
diff --git a/src/c3nav/mapdata/render/renderer.py b/src/c3nav/mapdata/render/renderer.py
index 42cbe20d..b7143356 100644
--- a/src/c3nav/mapdata/render/renderer.py
+++ b/src/c3nav/mapdata/render/renderer.py
@@ -4,7 +4,7 @@ from shapely import prepared
 from shapely.geometry import box
 
 from c3nav.mapdata.cache import MapHistory
-from c3nav.mapdata.models import MapUpdate, Level
+from c3nav.mapdata.models import Level, MapUpdate
 from c3nav.mapdata.render.data import LevelRenderData, hybrid_union
 from c3nav.mapdata.render.engines.base import FillAttribs, StrokeAttribs