Initial Commit

Assets/Imstk/Scripts/StrainParameter.cs

@@ -0,0 +1,100 @@
+/*=========================================================================
+
+   Library: iMSTK-Unity
+
+   Copyright (c) Kitware, Inc. 
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0.txt
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+=========================================================================*/
+
+using Imstk;
+using UnityEngine;
+
+namespace ImstkUnity
+{
+
+    [RequireComponent(typeof(MeshFilter))]
+    /// <summary>
+    /// Assigns a set of strain parameters to a deformable object based on a mesh
+    /// Overlapping regions will be resolved in random order.
+    /// </summary>
+    /// This is used to assign different material properties to different regions of a deformable object.
+    /// in effect creating an anisotropic material. At the moment this is only supported for tetrahedral meshes
+    /// and strain parameters
+    public class StrainParameter : ImstkBehaviour
+    {
+        public MeshFilter region;
+        public Deformable deformable;
+        public bool hideRegion = true;
+
+        public Imstk.PbdFemConstraint.MaterialType materialType;
+        public double  youngsModulus = 5000.0;
+        public double possionsRatio = 0.4;
+
+        private void Start()
+        {
+            Debug.Assert(region != null);
+            Debug.Assert(deformable != null);
+            var renderer = region.gameObject.GetComponent<MeshRenderer>();
+            if (renderer != null && hideRegion)
+            {
+                renderer.enabled = false;
+            }
+        }
+
+        protected override void OnImstkInit()
+        {
+            // Make sure the deformable is initialized
+            deformable.ImstkInit();
+
+            var geom = deformable.GetPhysicsGeometry();
+            if (geom.getTypeName() != Imstk.TetrahedralMesh.getStaticTypeName())
+            {
+                Debug.LogError("StrainParameter: Deformable is not a TetrahedralMesh");
+                return;
+            }
+
+            // Initialize the strain parameters attribute if necessary
+            // Material -1 will be ignored
+            Imstk.TetrahedralMesh tetMesh = Imstk.Utils.CastTo<Imstk.TetrahedralMesh>(geom);
+            var strainParams = tetMesh.getStrainParameters();
+            if (strainParams == null)
+            {
+                strainParams = new VecDataArray3d(tetMesh.getNumCells());
+                for (uint i = 0; i < tetMesh.getNumCells(); i++)
+                {
+                    strainParams[i] = new Vec3d(-1, 0, 0);
+                }
+            }
+            
+            var pointSet = Imstk.Utils.CastTo<Imstk.PointSet>(tetMesh);
+            var pointsInside = GeomUtil.PointsInside(region, pointSet);
+            double materialNumber = (double)materialType;
+            foreach (var point in pointsInside)
+            {
+                if (point >= 0)
+                {
+                    var cells = tetMesh.getCellsForVertex((int)point);
+                    foreach (var cell in cells)
+                    {
+                        strainParams[(uint)cell] = new Vec3d(materialNumber, youngsModulus, possionsRatio);
+                    }
+                }
+            }
+
+            tetMesh.setStrainParameters(strainParams);
+        }
+    }
+
+}