diff --git a/combine_obj.py b/combine_obj.py
new file mode 100644
index 0000000..b02b523
--- /dev/null
+++ b/combine_obj.py
@@ -0,0 +1,83 @@
+from collections import defaultdict
+import sys
+from obj import parse_obj_file
+from obj import VertexPosition
+from obj import VertexNormal
+from obj import VertexTexture
+from obj import ObjFile
+from obj import Object
+from obj import Face
+from obj import FacePTN
+from generate import renderer
+from generate_cpp import generate_obj_file
+
+global_vertex = {
+    VertexPosition: {},
+    VertexNormal: {},
+    VertexTexture: {},
+}
+
+global_names = defaultdict(int)
+
+def merge_vertex(vertex, type):
+    d = global_vertex[type]
+    if vertex not in d:
+        d[vertex] = len(d)
+
+def merge_vertices(vertices, type):
+    for vertex in vertices:
+        merge_vertex(vertex, type)
+
+def rewrite_ptn(obj_file, ptn):
+    return FacePTN(
+        position=global_vertex[VertexPosition][obj_file.position[ptn.position]],
+        normal=global_vertex[VertexNormal][obj_file.normal[ptn.normal]],
+        texture=global_vertex[VertexTexture][obj_file.texture[ptn.texture]],
+    )
+
+def rewrite_face(obj_file, face):
+    return Face(
+        ptn=[rewrite_ptn(obj_file, face_ptn) for face_ptn in face.ptn]
+    )
+
+def rewrite_object(obj_file, object):
+    global global_names
+    global_names[object.name] += 1
+    name_suffix = global_names[object.name]
+    return Object(
+        name=f"{object.name}_{name_suffix}",
+        faces=[rewrite_face(obj_file, face) for face in object.faces],
+        material=object.material,
+    )
+
+def rewrite_objects(obj_files):
+    for obj_file in obj_files:
+        for object in obj_file.objects:
+            yield rewrite_object(obj_file, object)
+
+def reorder_vertices(type):
+    d = global_vertex[type]
+    dd = {v: k for k, v in d.items()}
+    for i in range(len(dd)):
+        yield dd[i]
+
+def rewrite_obj_file(obj_files):
+    for obj_file in obj_files:
+        merge_vertices(obj_file.position, VertexPosition)
+        merge_vertices(obj_file.normal, VertexNormal)
+        merge_vertices(obj_file.texture, VertexTexture)
+
+    return ObjFile(
+        position=reorder_vertices(VertexPosition),
+        normal=reorder_vertices(VertexNormal),
+        texture=reorder_vertices(VertexTexture),
+        objects=list(rewrite_objects(obj_files))
+    )
+
+if __name__ == "__main__":
+    filenames = sys.argv[2:]
+    obj_files = [parse_obj_file(fn) for fn in filenames]
+    obj_file = rewrite_obj_file(obj_files)
+    render, out = renderer(indent_length=4)
+    render(generate_obj_file(sys.argv[1], obj_file))
+    sys.stdout.write(out.getvalue())
diff --git a/generate_cpp.py b/generate_cpp.py
index 5b728fb..9bd1e75 100644
--- a/generate_cpp.py
+++ b/generate_cpp.py
@@ -4,11 +4,11 @@ import sys
 
 def generate_vec3(vs):
     for v in vs:
-        yield f"{{{v.x:.6f}f, {v.y:.6f}f, {v.z:.6f}f}},"
+        yield f"{{{v.x.to_string()}f, {v.y.to_string()}f, {v.z.to_string()}f}},"
 
 def generate_vec2(vs):
     for v in vs:
-        yield f"{{{v.x:.6f}f, {v.y:.6f}f}},"
+        yield f"{{{v.x.to_string()}f, {v.y.to_string()}f}},"
 
 def generate_vec(name, type, func, vs):
     yield f"const vertex_{type} {name}_{type}[] = {{"
diff --git a/obj.py b/obj.py
index 49089c7..f805a3c 100644
--- a/obj.py
+++ b/obj.py
@@ -2,23 +2,36 @@ from dataclasses import dataclass
 import sys
 import os
 
+@dataclass(frozen=True)
+class FixedPoint:
+    s: int # sign
+    w: int # whole
+    f: int # fraction
+    b: int # base
+
+    def to_string(self):
+        s_s = "-" if self.s < 0 else ""
+        w_s = f"{self.w}"
+        f_s = f"{self.f}".rjust(self.b, '0')
+        return f"{s_s}{w_s}.{f_s}"
+
 @dataclass(frozen=True)
 class VertexPosition:
-    x: float
-    y: float
-    z: float
+    x: FixedPoint
+    y: FixedPoint
+    z: FixedPoint
 
 @dataclass(frozen=True)
 class VertexNormal:
-    x: float
-    y: float
-    z: float
+    x: FixedPoint
+    y: FixedPoint
+    z: FixedPoint
 
 @dataclass(frozen=True)
 class VertexTexture:
-    x: float
-    y: float
-    z: float
+    x: FixedPoint
+    y: FixedPoint
+    z: FixedPoint
 
 @dataclass(frozen=True)
 class ObjectEvent:
@@ -44,10 +57,10 @@ class Object:
     faces: list[Face]
     material: Material
 
-    def __init__(self, name):
+    def __init__(self, name, faces=None, material=None):
         self.name = name
-        self.faces = []
-        self.material = None
+        self.faces = [] if faces is None else faces
+        self.material = material
 
 @dataclass
 class ObjFile:
@@ -56,11 +69,11 @@ class ObjFile:
     texture: list[VertexTexture]
     objects: list[Object]
 
-    def __init__(self):
-        self.position = []
-        self.normal = []
-        self.texture = []
-        self.objects = []
+    def __init__(self, position=None, normal=None, texture=None, objects=None):
+        self.position = [] if position is None else position
+        self.normal = [] if normal is None else normal
+        self.texture = [] if texture is None else texture
+        self.objects = [] if objects is None else objects
 
 def parse_float(s):
     sign = -1 if s.startswith("-") else 1
@@ -72,14 +85,7 @@ def parse_float(s):
     i = int(i, 10)
     f = int(f, 10)
 
-    if 'ROUND_PRECISION' in os.environ:
-        max_digits = 4
-        if f_digits > max_digits:
-            f = int(f / (f_digits - max_digits))
-        f_digits = max_digits
-
-    f_10 = (f / 10 ** f_digits)
-    return sign * (i + f_10)
+    return FixedPoint(sign, i, f, f_digits)
 
 def parse_vertex(line, n, type):
     assert len(line) == n