diff --git a/convert.py b/convert.py
index 54c6560..01f302f 100755
--- a/convert.py
+++ b/convert.py
@@ -3,9 +3,8 @@
 import argparse
 import os
 
-from d3.model.ply import PLYExporter
-from d3.model.tools import convert
-from functools import partial
+import d3.model.tools as mt
+import functools as fc
 
 def check_path(path, should_exist):
     """ Check that a path (file or folder) exists or not and return it.
@@ -18,7 +17,7 @@ def check_path(path, should_exist):
 
 def main(args):
     output = args.output if args.output is not None else '.' + args.type
-    result = convert(args.input, output)
+    result = mt.convert(args.input, output)
 
     if args.output is None:
         print(result)
@@ -31,7 +30,7 @@ if __name__ == '__main__':
     parser.set_defaults(func=main)
     parser.add_argument('-v', '--version', action='version', version='1.0')
     parser.add_argument('-i', '--input', metavar='input',
-                        type=partial(check_path, should_exist=True), default=None,
+                        type=fc.partial(check_path, should_exist=True), default=None,
                         help='Input file (.obj)')
     parser.add_argument('-o', '--output', metavar='output',
                         help='Output path')
diff --git a/d3/controls.py b/d3/controls.py
index 6f2a6b4..60894e7 100644
--- a/d3/controls.py
+++ b/d3/controls.py
@@ -3,10 +3,7 @@
 from .geometry import Vector
 
 import pygame
-
-from OpenGL.GL import *
-from OpenGL.GLU import *
-
+import OpenGL.GL as gl
 import math
 
 class Controls:
@@ -26,7 +23,7 @@ class TrackBallControls(Controls):
         self.theta = 0
 
     def apply(self):
-        glRotatef(self.theta * 180 / math.pi, self.vertex.x, self.vertex.y, self.vertex.z)
+        gl.glRotatef(self.theta * 180 / math.pi, self.vertex.x, self.vertex.y, self.vertex.z)
 
     def update(self, time = 10):
 
diff --git a/d3/geometry.py b/d3/geometry.py
index a30d7bf..15822d4 100644
--- a/d3/geometry.py
+++ b/d3/geometry.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-from math import sqrt
+import math
 
 class Vector:
     def __init__(self, x = 0.0, y = 0.0, z = 0.0):
@@ -27,7 +27,7 @@ class Vector:
         return self.x * self.x + self.y * self.y + self.z * self.z
 
     def norm(self):
-        return sqrt(self.norm2())
+        return math.sqrt(self.norm2())
 
     def normalize(self):
         norm = self.norm()
diff --git a/viewer.py b/viewer.py
index 37a696e..eb3204e 100755
--- a/viewer.py
+++ b/viewer.py
@@ -2,15 +2,14 @@
 
 import sys
 import ctypes
-import pygame
 import argparse
 import os
 import math
 
-from pygame.locals import *
-from OpenGL.GL import *
-from OpenGL.GL.shaders import *
-from OpenGL.GLU import *
+import pygame as pg
+import pygame.locals as pgl
+import OpenGL.GL as gl
+import OpenGL.GLU as glu
 
 from d3.model.tools import load_model
 from d3.geometry import Vector
@@ -26,20 +25,20 @@ def main(args):
     camera = Camera(Vector(0,0,5), Vector(0,0,0))
     controls = TrackBallControls()
 
-    pygame.init()
+    pg.init()
     display = (WINDOW_WIDTH, WINDOW_HEIGHT)
-    pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
+    pg.display.set_mode(display, pgl.DOUBLEBUF | pgl.OPENGL)
 
     # OpenGL init
-    glMatrixMode(GL_PROJECTION)
-    glLoadIdentity()
-    gluPerspective(45, (WINDOW_WIDTH / WINDOW_HEIGHT), 0.1, 50.0)
+    gl.glMatrixMode(gl.GL_PROJECTION)
+    gl.glLoadIdentity()
+    glu.gluPerspective(45, (WINDOW_WIDTH / WINDOW_HEIGHT), 0.1, 50.0)
 
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
-    glEnable(GL_DEPTH_TEST)
-    glEnable(GL_CULL_FACE)
-    glEnable(GL_BLEND)
-    glClearColor(0, 0, 0, 0)
+    gl.glBlendFunc(gl.GL_SRC_ALPHA, gl.GL_ONE_MINUS_SRC_ALPHA)
+    gl.glEnable(gl.GL_DEPTH_TEST)
+    gl.glEnable(gl.GL_CULL_FACE)
+    gl.glEnable(gl.GL_BLEND)
+    gl.glClearColor(0, 0, 0, 0)
 
     running = True
 
@@ -49,40 +48,40 @@ def main(args):
     shader = DefaultShader()
 
     while running:
-        for event in pygame.event.get():
-            if event.type == pygame.QUIT:
-                pygame.quit()
+        for event in pg.event.get():
+            if event.type == pg.QUIT:
+                pg.quit()
                 quit()
-            elif event.type == pygame.KEYUP:
-                if event.key == pygame.K_ESCAPE:
-                    pygame.quit()
+            elif event.type == pg.KEYUP:
+                if event.key == pg.K_ESCAPE:
+                    pg.quit()
                     quit()
-            elif event.type == pygame.MOUSEBUTTONDOWN:
+            elif event.type == pg.MOUSEBUTTONDOWN:
                 if event.button == 1:
-                    pygame.mouse.get_rel()
+                    pg.mouse.get_rel()
 
         # Update physics
         controls.update()
 
 
-        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
-        glMatrixMode(GL_MODELVIEW)
-        glLoadIdentity()
+        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)
+        gl.glMatrixMode(gl.GL_MODELVIEW)
+        gl.glLoadIdentity()
 
         camera.look()
 
-        glPushMatrix()
+        gl.glPushMatrix()
         controls.apply()
         shader.bind()
         model.gl_draw()
         shader.unbind()
-        glPopMatrix()
+        gl.glPopMatrix()
 
-        glFlush()
-        pygame.display.flip()
+        gl.glFlush()
+        pg.display.flip()
 
         # Sleep
-        pygame.time.wait(10)
+        pg.time.wait(10)
 
 
 if __name__ == '__main__':