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bevel -- Functions for cutting meshes at edges or points, like chamfer

This module provides the chamfer and filet functions, and the associated tools.

edgecut, chamfer, and filet are built using the same cutting algorithm. It cuts the mesh faces by propagation from the given edges. The cutting planes are determined by an offset vector from the original primitive (point or edge).

Most of the time you don't need to set the offset yourself. It can be automatically calculated by several methods, depending on the shape you want to get. Those methods are called cutters and are executed using planeoffsets.

bevel cutter

End-user functions

chamfer(mesh, indices, **cutter)

Cut the given edges or points on the mesh and replace them by a chamfer: a flat surface filling the hole

Example

    >>> cube = brick(width=5)
    >>> chamfer(cube, cube.frontiers(), width=1)
Source code in madcad/bevel.py 
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@singledispatch
def chamfer(mesh, indices, **cutter):
	''' Cut the given edges or points on the mesh and replace them by a chamfer: a flat surface filling the hole

	Example

		>>> cube = brick(width=5)
		>>> chamfer(cube, cube.frontiers(), width=1)
	'''
	raise TypeError('wrong argument type: {}'.format(type(mesh)))

chamfer scheme chamfer result

filet(mesh, indices, **cutter)

Cut the given edges or points on the mesh and replace them by a filet: a round surface tangenting and filling the hole

Example

    >>> cube = brick(width=5)
    >>> filet(cube, cube.frontiers(), width=1)
Source code in madcad/bevel.py 
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@singledispatch
def filet(mesh, indices, **cutter):
	''' Cut the given edges or points on the mesh and replace them by a filet: a round surface tangenting and filling the hole

	Example

		>>> cube = brick(width=5)
		>>> filet(cube, cube.frontiers(), width=1)
	'''
	raise TypeError('wrong argument type: {}'.format(type(mesh)))

filet scheme filet result

edgecut(mesh, indices, **cutter)

Cut a Mesh/Web/Wire around the given edges/points, using the given cutter

Source code in madcad/bevel.py 
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@singledispatch
def edgecut(mesh, indices, **cutter):
	''' Cut a Mesh/Web/Wire around the given edges/points, using the given cutter '''
	raise TypeError('wrong argument type: {}'.format(type(mesh)))

edgecut scheme edgecut result

Cutters (cut methods)

cutter_width(width, fn1, fn2)

Plane offset for a cut based on the width of the filet

Source code in madcad/bevel.py 
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def cutter_width(width, fn1, fn2):
	''' Plane offset for a cut based on the width of the filet '''
	n = normalize(fn1+fn2)
	s = dot(fn1,n)
	return -width/2 * sqrt(1/s**2 - 1) * n

cutter_distance(depth, fn1, fn2)

Plane offset for a cut based on the distance to the cutted edge

Source code in madcad/bevel.py 
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def cutter_distance(depth, fn1, fn2):
	''' Plane offset for a cut based on the distance to the cutted edge '''
	n = normalize(fn1 +fn2)
	cos_b = dot(fn1, n)
	cos_a = sqrt(1-cos_b**2)
	return -depth * n * cos_a

cutter_depth(dist, fn1, fn2)

Plane offset for a cut based on the distance along the side faces

Source code in madcad/bevel.py 
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def cutter_depth(dist, fn1, fn2):
	"""Plane offset for a cut based on the distance along the side faces"""
	return -dist * cross(normalize(cross(fn1,fn2)), fn1-fn2)

cutter_radius(depth, fn1, fn2)

Plane offset for a cut based on the angle between faces

Source code in madcad/bevel.py 
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def cutter_radius(depth, fn1, fn2):
	''' Plane offset for a cut based on the angle between faces '''
	n = normalize(fn1 + fn2)
	s = dot(fn1,n)
	return -depth * (1/s - s) * n