vcTriangleSet

vcTriangleSet is a geometry set used for creating and storing a collection of triangles and tessellated surface data.

Properties
Methods
Examples

Properties

Name	Type	Access	Description
CreaseAngle	Real	RW	Defines angle tolerance for triangle edge shading in which edge angles less than tolerance are rendered as smooth surfaces during light calculations.
DynamicTextureCoordinates1	Boolean	RW	Defines if texture coordinates of set can be updated during simulation.
DynamicUpdate	Boolean	RW	Defines if geometry of set can be updated during simulation.
Name	String	RW	Defines the name of set.
PointCount	Integer	R	Gets the total number of points in set.
PolygonCount	Integer	R	Gets the total number of triangles in set.
PolygonTable	List of Integer	RW	Defines a polygon table in the form of an ordered list used for generating triangles of set. In order to generate triangles, the vertex count of polygon is given first followed by the index for each vertex and so on for each subsequent polygon. For example, [3,0,1,2,3,0,2,3] would define two polygons with each having three vertices in which two are shared. Any polygon with four or more vertices will be tessellated. The actual positions of vertices are defined in PositionTable. See Example. Use polygon table to generate triangles for more information.
PositionTable	List of Real	RW	Defines a position table in the form of an ordered list used for generating triangles of set. In order to generate triangles, position values should have a known index and be in XYZ order. For example, [123.0,45.0,4.5,15.0,45.0,90.0] would define the position of two points which are aligned on Y-axis. If the number of entries is not enough for all points in set, those points will be deleted from set as a clean up operation. If number is more than is needed for points, additional points are created in set.
TextureCoordinateTable	List of Real	RW	Gets/Sets texture coordinates for points in set. f the number of entries is not enough for all points in set, those points will be deleted from set as a clean up operation. If number is more than is needed for points, additional points are created in set.
Topology	vcTopology	R	Gets the container of topology data for points in set.
TriangleCount	Integer	R	Gets the total number of triangles in set.
TriangleTable	List of Integer	RW	Gets/Sets the triangle table of set, which is an ordered list of vertex indices for each triangle.
UseTextureCoordinates1	Boolean	RW	Turns on/off the use of texture coordinates in set.

Methods

Name	Return Type	Parameters	Description
addPoint	Integer	vcVector vector or Real x, Real y, Real z	Adds a point to set, and then returns index of point in set.
addTriangle	Integer	Integer vertex1, Integer vertex2, Integer vertex3	Adds a triangle to set, and then returns new triangle count of set. See Example. Create sphere with triangle sets for more information.
collapsePoint	None	Integer indexPoint1, Integer indexPoint2	Collapses a point at a given index into another point at a given index in set, thereby updating triangles referencing first point to now reference second point. Generally, this is used to clean up redundant vertices, reduce data count or simplify geometry.
convexHull	vcTriangleSet	Boolean value	Creates a convex hull from geometry of set. If value is True, returns a new triangle set containing the resultant geometry. If value is False, modifies the current geometry of set and returns the same set.
decimate	Real	Real quality, Real maxError	Simplifies triangles of set by merging points within a given maxError tolerance until a given quality level is achieved or tolerance is exceeded.
decompose	None	None	Regroups triangles in set into different sets based on the connection of each triangle to one another.
deleteTriangle	None	Integer index	Deletes a triangle at a given index in set. You should call the update() method after deleting one or more triangles from set.
getClosestPointAndNormal	2-tuple (vcVector point, vcVector normal)	vcVector referencePoint	Returns the closest point to a given referencePoint in the set. The object coordinate system of the set is used to find the point, which is returned along with its surface normal.
getTexCoord1	2-tuple (Real u, Real v)	Integer index	Returns the texture coordinates of a point at a given index in set.
getTextureCoordinates	List of 2-tuple (Real u, Real v)	List of Integer indices	Returns a list containing an ordered pair of UV coordinates for points at given indices in set.
getPoint	vcVector	Integer index	Returns the position vector of point at a given index in set.
getPointIndexesWithin	List of Integer	vcVector position, Real side_length or vcVector position, Real side_length, vcVector normal	Returns a list of indices for points in set within an area defined by a given position and side_length. A normal argument can be given to filter points with the same surface normal. See Example. Get position of points for more information.
getPointNormals	List of vcVector	List of Integer indices or List of Integer indices, vcMatrix convert	Returns a list of surface normal vectors for points at a given list of indices in set. A convert argument can be used to transform each vector by a given matrix.
getPointPositions	List of vcVector	List of Integer indices or List of Integer indices, vcMatrix convert	Returns a list of position vectors for points at a given list of indices in set. A convert argument can be used to transform each vector by a given matrix.
getTriangle	3-tuple (Integer vertex1, Integer vertex2, Integer vertex3)	Integer index	Returns the indices of vertices for a triangle at a given index in set.
getTriangleEdgeNeighbor	2-tuple (Integer triangle_index, Integer vertex_index)	Integer index, Integer vertex	Returns the index of a triangle neighboring another triangle at a given index and vertex in set. The vertex argument should be either 0, 1 or 2. The returned value is an ordered pair identifying neighboring triangle and shared vertex in set.
getTriangleEdgeType	Enumeration	Integer index, Integer vertex	Returns the type of edge for a triangle at a given index and vertex in set. The vertex argument should be either 0, 1 or 2. The returned type is one of seven possibilities: 0 = UNKOWN Type is unknown. 1 = LINE No triangle attached to edge. 2 = CO_PLANAR Two triangles attached to edge and their surface normals are parallel. 3 = SOFT Two triangles attached to edge and angle between surface normals is within angle tolerance of set, that is smooth surface. 4 = HARD Two triangles attached to edge and angle between surface normals is outside angle tolerance of set, that is coarse surface. 5 = BOUNDARY One triangle attached to edge. 6 = NON_MANIFOLD More than two triangles attached to edge.
getTriangleNormal	vcVector	Integer index	Returns the surface normal of a triangle at a given index in set.
mergePoints	None	Real tolerance or Real tolerance, Boolean onlyBoundaryPoints	Merges points of triangles within a given tolerance that are not connected to one another by adding lines. A onlyBoundaryPoints argument can be used to only merge points that border one another and that are within the given tolerance.
setPoint	None	Integer index, vcVector vector	Sets the position vector of a point at a given index in set.
setTexCoord1	None	Integer index, Real u, Real v	Sets the texture coordinates of a point at a given index in set.
setTextureCoordinates	None	List of Integer indices, List of 2-tuple (Real u, Real v) coordinates	Sets the texture coordinates of points at a given list of indices in set.
setTriangle	None	Integer index, Integer vertex1, Integer vertex2, Integer vertex3	Sets the vertex indices of a triangle at a given index in set.
subdivide	None	Real max_edge_length or Real max_edge_length, Integer max_triangles	Modifies triangles in set into smaller triangles with edge lengths smaller or equal to a given max_edge_length. A max_triangles argument can be given to stop subdivision when triangle count reaches a maximum limit.
update	None	None	Updates the set and its bound box.

Examples

Example. Use a polygon table to generate triangles

from vcCommand import *

def first_state():
  app = getApplication()
  comp = app.createComponent()
  feat = comp.RootFeature.createFeature(VC_GEOMETRY,'Geometry')
  tset = feat.Geometry.createGeometrySet(VC_TRIANGLESET)
  tset.PositionTable = [0.0,0.0,0.0,100.0,0.0,0.0,100.0,100.0,0.0,0.0,100.0,0.0]

  #Uncomment any of the three following lines to product the same result

  #tset.TriangleTable = [0,1,2,0,2,3]
  #tset.PolygonTable = [3,0,1,2,3,0,2,3]
  #tset.PolygonTable = [4,0,1,2,3]
  tset.update()
  feat.rebuild()
  comp.rebuild()
  app.render()

#------------------------------------------------------------------------------
addState( first_state )
#------------------------------------------------------------------------------

Example. Get position of points within an area filtered by direction

Clear cube and position frame are used to represent the area defined in getPointIndexesWithin() method with position and radius.

from vcScript import *
import vcVector

#create block and collapse to quickly create triangle set
comp = getComponent()
gf = comp.findFeature('Geometry')
if gf == None:
  gf = comp.RootFeature.createFeature(VC_BLOCK, 'Geometry')
  gf.collapse()

#get triangle set
gc = gf.Geometry
tset = gc.GeometrySets[0]

#use PositionTable to get position of every point in TriangleSet
tset_points = tset.PositionTable

#use position and radius to get position of points within area
position = vcVector.new(50,100,100)
point_index = tset.getPointIndexesWithin(position, 50.0)
point_positions = tset.getPointPositions(point_index)
print point_index

#get point normals to filter
point_normals = tset.getPointNormals(tset.TriangleTable)
for i in range(len(point_normals)):
  for filter in point_normals:
    point_index = tset.getPointIndexesWithin(position, 50.0, filter)
    print point_index

Example. Create sphere with triangle sets

from vcScript import *
import vcVector
import vcMatrix

r = vcVector.new(100.0,0.0,0.0) # Radius of the sphere is 100.0
m = vcMatrix.new()

geofeat = getComponent().RootFeature.createFeature(VC_GEOMETRY,'MyGeometry')
tset = geofeat.Geometry.createGeometrySet(VC_TRIANGLESET)

for i in range(0,361,15): # Step every 15 degrees around Z (first and last coincident)
  for j in range(90,-91,-15): # Half circle in 12 sections around Y,
                                            # starting from south pole
    m.identity() # always reset the origin before rotate
    m.rotateRelZ(i)
    m.rotateRelY(j)
    p = m * r       # transform the radius vector with reoriented origin
    tset.addPoint(p)

for i in range(26): # i is the section around Z (12 in each)
  for j in range(12): # is around the rotating y axis
    tset.addTriangle(i*12+j,(i+1)*12+j,(i+1)*12+j+1)
    tset.addTriangle(i*12+j+1,i*12+j,(i+1)*12+j+1)

geofeat.rebuild()
getApplication().render()

Example. Access geometry and polygon data

from vcScript import *

comp = getComponent()
geoFea = comp.findFeature("Geometry")
geoCont = geoFea.Geometry
for i in geoCont.GeometrySets:
  print i.PolygonTable
  print i.PolygonCount
  print i.PointCount