SlyCodePanda · January 15, 2020 05:27 · Jan 15, 2020 · Jan 15, 2020
diff --git a/rayCasting.py b/rayCasting.py
@@ -0,0 +1,126 @@
+import maya.OpenMaya as om
+import maya.cmds as cmds
+
+
+def RayIntersect(mesh, point, direction):
+    # Clear selection.
+    cmds.select(cl=True)
+
+    # Select mesh.
+    om.MGlobal.selectByName(mesh)
+    selList = om.MSelectionList()
+
+    # Return an MSelectionList containing the nodes currently selected.
+    om.MGlobal.getActiveSelectionList(selList)
+
+    # Constructor that returns a new, empty MDagPath object.
+    item = om.MDagPath()
+
+    selList.getDagPath(0, item)
+
+    # Extends the path to the specified shape node parented directly beneath
+    # the transform.
+    item.extendToShape()
+
+    # Returns a new MFnMesh object attached to the given mesh node.
+    fnMesh = om.MFnMesh(item)
+
+    # Creates a 3D point with single precision coordinates.
+    # passed x, y, z, w coordinates.
+    raySource = om.MFloatPoint(point[0], point[1], point[2], 1.0)
+
+    # Creates a 3D vector with specified x, y, z coordinates.
+    rayDir = om.MFloatVector(direction[0], direction[1], direction[2])
+
+    # If faceIDs are specified, then only those faces will be considered for
+    # intersection.
+    faceIDs = None
+    # If both faceIDs and triIDs are given, then the triIDs will be interpreted
+    # as face-relative and each pair of entries will be takes as a
+    # (face, triangle) pair to be considered for intersection.
+    triIDs = None
+
+    # Set this to True if the faceIDs or triIDs arrays are properly sorted into
+    # ascending order.
+    IDsSorted = False
+
+    # maxParam and testBothDirections flags can be used to control the radius
+    # of the search around the raySource point.
+    testBothDirections = False
+    maxParam = 999999
+
+    # MSpace class providing coordinate space constraints.
+    # Calling space type 'kWorld'.
+    worldSpace = om.MSpace.kWorld
+
+    # If accelParams is given then the mesh builds an intersection acceleration
+    # structure based on it. This is used to speed up the intersection
+    # operation.
+    accelParams = None
+    # If true, then hits will be sorted in ascending ray-parametric order, so
+    # hits behind the ray source will be first (if testing both directions).
+    sortHits = True
+
+    # Array of MFloatPoint values.
+    hitPoints = om.MFloatPointArray()
+
+    hitRayParams = om.MFloatArray()
+    hitFaces = om.MIntArray()
+    hitTris = None
+    hitBarys1= None
+    hitBarys2 = None
+
+    # Numerical tolerance of the intersection operation.
+    tolerance = 0.0001
+
+    # Finds all intersection of a ray starting at raySource and travelling in
+    # rayDirection with the mesh.
+    hit = fnMesh.allIntersections(raySource, rayDir, faceIDs, triIDs, IDsSorted,
+                                  worldSpace, maxParam, testBothDirections,
+                                  accelParams, sortHits, hitPoints,
+                                  hitRayParams, hitFaces, hitTris, hitBarys1,
+                                  hitBarys2, tolerance)
+    '''
+    If the ray hits the mesh, the details of the intersection points will be
+    returned as a tuple containing the following:
+    
+        * hitPoints (MFloatPointArray) - coordinates of the points hit, in the
+                                         space specified by the caller.
+        * hitRayParams (MFloatArray) - parametric distances along the ray to the
+                                       points hit.
+        * hitFaces (MIntArray) - IDs of the faces hit.
+        * hitTriangles (MIntArray) - face-relative IDs if the triangle hit.
+        * hitBary1s (MFloatArray - First barycentric coordinate of the points
+                                   hit. If the vertices of the hitTriangle are
+                                   (v1, v2, v3) then the barycentric coordinates
+                                   are such that the hitPoint = 
+                                   (*hitBary1)*v1 + (*hitBary2)*v2 + 
+                                   (1-*hitBary1-*hitBary2)*v3.
+        * hitBary2s (MFloatArray) - second barycentric coordinate of the points
+                                    hit.
+    
+    If no point was hit then the arrays will all be empty.
+    '''
+
+'''
+REFS:
+
+https://help.autodesk.com/view/MAYAUL/2016/ENU/?guid=__py_ref_class_open_maya_1_1_m_fn_mesh_html
+https://www.youtube.com/watch?v=kjp2G7ndzZc
+
+TESTING:
+
+import sys
+
+sys.path.append('/home/reneem/dev/localDev')
+
+import rayCast as rc
+reload(rc)
+
+dir = (0.0, 0.0, -1.0)
+pnt = (0, 0, 3.774)
+msh = "pSphereShape1"
+rayCst = rc.RayIntersect(msh, pnt, dir)
+firstHit = (rayCst[0].x, rayCst[0].y, rayCst[0].z)
+
+'''
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