diff --git a/src/SimNDT/core/simulation.py b/src/SimNDT/core/simulation.py
new file mode 100644
index 0000000..d7ebb5f
--- /dev/null
+++ b/src/SimNDT/core/simulation.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+# encoding: utf-8
+"""
+simulation.py
+
+Created by Miguel Molero on 2013-09-30.
+Copyright (c) 2013 MMolero. All rights reserved.
+"""
+
+import numpy as np
+from scipy.misc import imresize
+from scipy.misc import imrotate
+
+from SimNDT.core.material import Material
+
+
+c11 = 4350*4350*7750
+c12 = 4350*4350*7750 - 2260*2260*7750
+c22 = c11
+c44 = 2260*2260*7750
+pzt = Material("pzt",7750.0, c11, c12, c22, c44)
+
+
+
+class Simulation:
+
+    def __init__(self, TimeScale=1, MaxFreq=2, PointCycle=10, SimTime=50, Order=2, Device ="CPU"):
+
+        self.TimeScale         = TimeScale
+        self.MaxFreq           = MaxFreq
+        self.PointCycle        = PointCycle
+        self.SimulationTime    = SimTime
+
+        self.dx = 0
+        self.dt = 0
+        # self.dx = Dx
+        # self.dt = Dt
+        self.t  = 0
+        self.Order    = Order
+        self.Device   = Device
+        self.Platform = 0
+        self.MRI = 0
+        self.NRI = 0
+        self.Im  = 0
+        self.TapGrid   = 0
+        self.Rgrid     = 0
+        self.TimeSteps = 0
+
+    def job_parameters(self, materiales, transducer):
+
+        indVL = [mat.VL for mat in materiales if mat.VL > 400]
+        indVT = [mat.VT for mat in materiales if mat.VT > 400]
+
+        if transducer.PZT:
+            indVL.append(pzt.VL)
+            indVL.append(pzt.VT)
+
+
+        VL	= np.array(indVL)
+        VT	= np.array(indVT)
+        V	= np.hstack( (VL, VT) )
+
+        self.dx = np.float32( np.min([V]) / (self.PointCycle * self.MaxFreq) )
+
+        if self.Order== 2:
+            self.dt = 0.5 * self.TimeScale * np.float32( 0.7071 * self.dx / (	 np.max([V]) ) )
+        elif self.Order == 4:
+            self.dt = self.TimeScale * np.float32( 0.48 * self.dx / (	 np.max([V]) ) )
+
+        self.TimeSteps = round(self.SimulationTime/self.dt)
+        self.t = self.dt*np.arange(0,self.TimeSteps)
+
+        print("Updated simulation job parameters dx="+str(self.dx)+" dt="+str(self.dt)+ " TimeSteps="+str(self.TimeSteps)+" t="+str(self.t))
+
+    def jobByUser(self, dx, dt):
+
+        self.dx = dx
+        self.dt = dt
+
+        self.TimeSteps = round(self.SimulationTime/self.dt)
+        self.t = self.dt*np.arange(0,self.TimeSteps)
+
+    def create_numericalModel(self, scenario):
+
+        #Spatial Scale
+        Pixel_mm = float(scenario.Pixel_mm)
+
+        Mp	= np.shape(scenario.Iabs)[0]*1e-3/Pixel_mm/self.dx
+        self.Rgrid = float(Mp/np.shape(scenario.Iabs)[0])
+        self.TapGrid = np.around(scenario.Tap * self.Rgrid)
+        self.Im = imresize(scenario.Iabs, self.Rgrid, interp='nearest')
+        self.MRI, self.NRI = np.shape(self.Im)
+
+
+    def rotate_model(self, theta, scenario):
+        Theta = theta * (180.0/np.pi) - 270.
+        if Theta != 0:
+            print ("type scenario: ", np.shape(scenario.I))
+            I = imrotate(np.uint8(scenario.I), Theta, interp ='nearest')
+            print ("type scenario I: ", np.shape(I))
+            Iabs = scenario.applyBoundaries(I)
+            self.Im = imresize(np.uint8(Iabs), self.Rgrid, interp='nearest')
+            self.MRI, self.NRI = np.shape(self.Im)
+
+
+
+    def setDevice(self,Device):
+        self.Device = Device
+
+    def setPlatform(self, Platform):
+        self.Platform = Platform
+
+
+    def reLoad(self, Materials, Scenario, Transducer):
+
+        self.job_parameters(Materials, Transducer)
+        self.create_numericalModel(Scenario)
+        
+    def __str__(self):
+        return "Simulation(TimeScale={}, MaxFreq={}, PointCycle={}, SimulationTime={}, Order={}, Device={})".format(
+            self.TimeScale, self.MaxFreq, self.PointCycle, self.SimulationTime, self.Order, self.Device
+        )
+
+    def __repr__(self):
+        return "Simulation(TimeScale={}, MaxFreq={}, PointCycle={}, SimulationTime={}, Order={}, Device={} dx={} dt={})".format(
+            self.TimeScale, self.MaxFreq, self.PointCycle, self.SimulationTime, self.Order, self.Device, self.dx, self.dt
+        )