diff --git a/src/c3nav/mapdata/render/engines/base.py b/src/c3nav/mapdata/render/engines/base.py
index 720cdba8..cfdf169d 100644
--- a/src/c3nav/mapdata/render/engines/base.py
+++ b/src/c3nav/mapdata/render/engines/base.py
@@ -29,11 +29,13 @@ class RenderEngine(ABC):
     filetype = 'dat'
 
     # draw an svg image. supports pseudo-3D shadow-rendering
-    def __init__(self, width: int, height: int, xoff=0, yoff=0, scale=1, buffer=0, background='#FFFFFF', center=True):
+    def __init__(self, width: int, height: int, xoff=0, yoff=0, zoff=0,
+                 scale=1, buffer=0, background='#FFFFFF', center=True):
         self.width = width
         self.height = height
         self.minx = xoff
         self.miny = yoff
+        self.base_z = zoff
         self.scale = scale
         self.orig_buffer = buffer
         self.buffer = int(math.ceil(buffer*self.scale))
diff --git a/src/c3nav/mapdata/render/engines/opengl.py b/src/c3nav/mapdata/render/engines/opengl.py
index 1803d4a9..5fbaf805 100644
--- a/src/c3nav/mapdata/render/engines/opengl.py
+++ b/src/c3nav/mapdata/render/engines/opengl.py
@@ -153,10 +153,10 @@ class OpenGLEngine(Base3DEngine):
 
         scale_x = self.scale / self.width * 2
         scale_y = self.scale / self.height * 2
-        scale_z = (scale_x+scale_y) / 2
+        scale_z = 0.05
 
         self.gl_scale = (scale_x, -scale_y, scale_z)
-        self.gl_offset = (-self.minx * scale_x - 1, self.maxy * scale_y - 1, 0)
+        self.gl_offset = (-self.minx * scale_x - 1, self.maxy * scale_y - 1, -self.base_z * scale_z)
 
         self.vertices = []
 
diff --git a/src/c3nav/mapdata/render/renderdata.py b/src/c3nav/mapdata/render/renderdata.py
index 69a5bb2c..1177587e 100644
--- a/src/c3nav/mapdata/render/renderdata.py
+++ b/src/c3nav/mapdata/render/renderdata.py
@@ -37,6 +37,7 @@ class Cropper:
 class LevelRenderData:
     def __init__(self):
         self.levels = []
+        self.base_altitude = None
 
     @staticmethod
     def rebuild():
@@ -106,6 +107,7 @@ class LevelRenderData:
                         break
 
             render_data = LevelRenderData()
+            render_data.base_altitude = level.base_altitude
             access_restriction_affected = {}
 
             for sublevel in sublevels:
diff --git a/src/c3nav/mapdata/render/renderer.py b/src/c3nav/mapdata/render/renderer.py
index 6b6055ce..6af24459 100644
--- a/src/c3nav/mapdata/render/renderer.py
+++ b/src/c3nav/mapdata/render/renderer.py
@@ -29,9 +29,6 @@ class MapRenderer:
         return box(self.minx-1, self.miny-1, self.maxx+1, self.maxy+1)
 
     def render(self, engine_cls, center=True):
-        engine = engine_cls(self.width, self.height, self.minx, self.miny,
-                            scale=self.scale, buffer=1, background='#DCDCDC', center=center)
-
         # add no access restriction to “unlocked“ access restrictions so lookup gets easier
         access_permissions = self.access_permissions | set([None])
 
@@ -39,6 +36,9 @@ class MapRenderer:
 
         level_render_data = LevelRenderData.get(self.level)
 
+        engine = engine_cls(self.width, self.height, self.minx, self.miny, float(level_render_data.base_altitude),
+                            scale=self.scale, buffer=1, background='#DCDCDC', center=center)
+
         if self.full_levels:
             levels = tuple(chain(*(
                 tuple(sublevel for sublevel in LevelRenderData.get(level.pk).levels