Module Geometry

Module Geometry

The Blender.Geometry submodule.

Geometry

This new module provides access to a geometry function.

Function Summary
tuple	`BoxPack2D(boxlist)` Takes a list of 2D boxes and packs them into a square.
Vector	`LineIntersect2D(vec1, vec2, vec3, vec4)` Takes 2 lines vec1, vec2 for the 2 points of the first line and vec2, vec3 for the 2 points of the second line.
bool	`PointInTriangle2D(pt, tri_pt1, tri_pt2, tri_pt3)` Takes 4 vectors (one for the test point and 3 for the triangle) This is a 2d function so only X and Y are used, Z and W will be ignored.
list	`PolyFill(polylines)` Takes a list of polylines and calculates triangles that would fill in the polylines.

Function Details

BoxPack2D(boxlist)

Takes a list of 2D boxes and packs them into a square. Each box in boxlist must be a list of at least 4 items - [x,y,w,h], after running this script, the X and Y values in each box will be moved to packed, non overlapping locations.

Example:

       # Make 500 random boxes, pack them and make a mesh from it
       from Blender import Geometry, Scene, Mesh
       import random
       boxes = []
       for i in xrange(500):
               boxes.append( [0,0, random.random()+0.1, random.random()+0.1] )
       boxsize = Geometry.BoxPack2D(boxes)
       print 'BoxSize', boxsize
       me = Mesh.New()
       for x in boxes:
               me.verts.extend([(x[0],x[1], 0), (x[0],x[1]+x[3], 0), (x[0]+x[2],x[1]+x[3], 0), (x[0]+x[2],x[1], 0) ])
               v1= me.verts[-1]
               v2= me.verts[-2]
               v3= me.verts[-3]
               v4= me.verts[-4]
               me.faces.extend([(v1,v2,v3,v4)])
       scn = Scene.GetCurrent()
       scn.objects.new(me)

Returns:: a tuple pair - (width, height) of all the packed boxes.
(type=tuple)

Note: Each boxlist item can be longer then 4, the extra items are ignored and stay untouched.

LineIntersect2D(vec1, vec2, vec3, vec4)

Takes 2 lines vec1, vec2 for the 2 points of the first line and vec2, vec3 for the 2 points of the second line.

Returns:: a 2D Vector for the intersection or None where there is no intersection.
(type=Vector)

PointInTriangle2D(pt, tri_pt1, tri_pt2, tri_pt3)

Takes 4 vectors (one for the test point and 3 for the triangle) This is a 2d function so only X and Y are used, Z and W will be ignored.

Returns:: True or False depending on the points intersection.
(type=bool)

PolyFill(polylines)

Takes a list of polylines and calculates triangles that would fill in the polylines. Multiple lines can be used to make holes inside a polyline, or fill in 2 seperate lines at once.

Parameters:: polylines
(type=List of lists containing vectors, each representing a closed polyline.)

Returns:: a list if tuples each a tuple of 3 ints representing a triangle indexing the points given.
(type=list)

Notes:

2D Vectors will have an assumed Z axis of zero, 4D Vectors W axis is ignored.

The order of points in a polyline effect the direction returned triangles face, reverse the order of a polyline to flip the normal of returned faces.

Example:

The example below creates 2 polylines and fills them in with faces, then makes a mesh in the current scene:

       import Blender
       Vector= Blender.Mathutils.Vector

       # Outline of 5 points
       polyline1= [Vector(-2.0, 1.0, 1.0), Vector(-1.0, 2.0, 1.0), Vector(1.0, 2.0, 1.0), Vector(1.0, -1.0, 1.0), Vector(-1.0, -1.0, 1.0)]
       polyline2= [Vector(-1, 1, 1.0), Vector(0, 1, 1.0), Vector(0, 0, 1.0), Vector(-1.0, 0.0, 1.0)]
       fill= Blender.Geometry.PolyFill([polyline1, polyline2])

       # Make a new mesh and add the truangles into it
       me= Blender.Mesh.New()
       me.verts.extend(polyline1)
       me.verts.extend(polyline2)
       me.faces.extend(fill) # Add the faces, they reference the verts in polyline 1 and 2

       scn = Blender.Scene.GetCurrent()
       ob = scn.objects.new(me)
       Blender.Redraw()

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