Added new function to build Scalar Field from Voxels

A new constructor for ScalarField allows you to build a new scalar field for all "surface/inside" voxels, using a default value. This is useful to build, for example, a for density domain for simulation exchange, for all voxels making up the fluid.

Requires PicoGK Runtime 1.6

Added usage example to Ex_SimulationSetup.cs

Examples/Ex_SimulationSetup.cs

@@ -179,14 +179,19 @@ VectorField oInletField
 
             Library.oViewer().SetGroupVisible(10, false);
 
+            // Create a new scalar field, which contains the density of water
+            // at all voxels which are in the fluid domain (997 kg/m³)
+            ScalarField oFluidDensity = new(voxFluid, 997.0f);
+
             OpenVdbFile oFile = new();
 
             voxFluid.m_oMetadata.SetValue("Simulation.Material.Name", "Water");
             voxFluid.m_oMetadata.SetValue("Simulation.Material.Type", "Liquid");
             oFile.nAdd(voxFluid, "Simulation.FluidDomain");
 
-            oFile.nAdd(voxManifold, "Simulation.SolidDomain");
-            oFile.nAdd(oFlowSpeed,  "Simulation.FlowSpeed");
+            oFile.nAdd(voxManifold,     "Simulation.SolidDomain");
+            oFile.nAdd(oFlowSpeed,      "Simulation.FlowSpeed");
+            oFile.nAdd(oFluidDensity,   "Simulation.FluidDensity");
 
             string strVdbFile = Path.Combine(Utils.strDocumentsFolder(), "Sim.vdb");
             oFile.SaveToFile(strVdbFile);

PicoGK_ScalarField.cs

@@ -79,14 +79,25 @@ public ScalarField(in ScalarField oSource)
 
         /// <summary>
         /// Creates a scalar field from an existing voxel field
-        /// the scalar field contains the signed distance values
+        /// setting the voxels inside the object to the specified value
         /// of the voxels
         /// </summary>
         /// <param name="oVoxels">Voxels to create SDF from</param>
+        /// <param name="fValue">Value to set the scalar field to</param>"
+        /// <param name="fSdThreshold">The threshold of the signed distance field
+        /// to be used for the definition of "inside" - usually 0.5 is a good
+        /// value - the surface is at exactly 0 and a value of
+        /// 1.0 means you are 1 voxel outside from the surface.</param>
         public ScalarField(Voxels oVoxels)
             : this(_hCreateFromVoxels(oVoxels.m_hThis))
         { }
 
+        public ScalarField( Voxels oVoxels,
+                            float fValue,
+                            float fSdThreshold = 0.5f)
+            : this(_hBuildFromVoxels(oVoxels.m_hThis, fValue, fSdThreshold))
+        {}
+
         /// <summary>
         /// Sets the value at the specified position in mm
         /// When you set a value, the position gets "activated"

PicoGK__Interop.cs

@@ -748,6 +748,9 @@ public partial class ScalarField : IDisposable
         [DllImport(Config.strPicoGKLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "ScalarField_hCreateFromVoxels")]
         public static extern IntPtr _hCreateFromVoxels(IntPtr hVoxels);
 
+        [DllImport(Config.strPicoGKLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "ScalarField_hBuildFromVoxels")]
+        public static extern IntPtr _hBuildFromVoxels(IntPtr hVoxels, float fScalarValue, float fSdThreshold);
+
         [DllImport(Config.strPicoGKLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "ScalarField_bIsValid")]
         private static extern bool _bIsValid(IntPtr hThis);