diff --git a/sample/gadgetToArray.cpp b/sample/gadgetToArray.cpp
index 386fa01..0bd0d0b 100644
--- a/sample/gadgetToArray.cpp
+++ b/sample/gadgetToArray.cpp
@@ -64,12 +64,12 @@ int main(int argc, char **argv)
 
   SimuData *p = loadGadgetMulti(fname, 0, 0);
   double L0 = p->BoxSize/1000;
-  array_type parts(boost::extents[p->TotalNumPart][6]);
+  array_type parts(boost::extents[p->TotalNumPart][7]);
   uint64_t q = 0;
   
   try {
     for (int cpuid=0;;cpuid++) {
-      p = loadGadgetMulti(fname, cpuid, NEED_POSITION|NEED_VELOCITY);
+      p = loadGadgetMulti(fname, cpuid, NEED_POSITION|NEED_VELOCITY|NEED_MASS);
       for (uint32_t i = 0; i < p->NumPart; i++)
         {
           parts[q][0] = p->Pos[0][i]/1000;
@@ -83,6 +83,7 @@ int main(int argc, char **argv)
           parts[q][3] = p->Vel[0][i];
           parts[q][4] = p->Vel[1][i];
           parts[q][5] = p->Vel[2][i];
+          parts[q][6] = p->Mass[i];
           q++;
         }
 
diff --git a/sample/simple3DFilter.cpp b/sample/simple3DFilter.cpp
index 345834c..bc3bd1d 100644
--- a/sample/simple3DFilter.cpp
+++ b/sample/simple3DFilter.cpp
@@ -17,6 +17,7 @@ using namespace CosmoTool;
 
 struct VCoord{
   float v[3];
+  float mass;
 };
 
 using boost::format;
@@ -27,12 +28,12 @@ typedef boost::multi_array<float, 4> array4_type;
 
 ComputePrecision getVelocity(const VCoord& v, int i)
 {
-  return v.v[i];
+  return v.mass * v.v[i];
 }
 
-ComputePrecision getUnity(const VCoord& v)
+ComputePrecision getMass(const VCoord& v)
 {
-  return 1.0;
+  return v.mass;
 }
 
 typedef SPHSmooth<VCoord> MySmooth;
@@ -198,7 +199,7 @@ int main(int argc, char **argv)
   array3_type interpolated(boost::extents[Nres][Nres][Nres]);
   
   computeInterpolatedField(&tree1, boxsize, Nres, cx, cy, cz,
-                           bins, interpolated, getUnity, rLimit2);
+                           bins, interpolated, getMass, rLimit2);
   hdf5_write_array(out_f, "density", interpolated);
   //out_f.flush();
   for (int i = 0; i < 3; i++) {