diff --git a/docs/reference/primitives.rst b/docs/reference/primitives.rst
index d7baae54..4196c5f5 100644
--- a/docs/reference/primitives.rst
+++ b/docs/reference/primitives.rst
@@ -36,7 +36,7 @@ Specification priority order:
 	
 	1. Optional argument ``resolution`` passed to ``primitive.mesh()`` or to ``web()`` or ``wire()``
 	2. Optional attribute ``resolution`` of the primitive object
-	3. Value of ``settings.primitives['curve_resolution']`` at bake time.
+	3. Value of ``settings.resolution`` at bake time.
 
 Specification format:
 
@@ -75,8 +75,8 @@ Primitives types
 	.. autoproperty:: direction
 	
 	.. image:: /screenshots/primitives-segment.png
-
-.. autoclass:: ArcCentered
+	
+.. autoclass:: Circle
 
 	.. autoproperty:: center
 	
@@ -86,9 +86,9 @@ Primitives types
 	
 	.. automethod:: tangent
 	
-	.. image:: /screenshots/primitives-arccentered.png
+	.. image:: /screenshots/primitives-circle.png
 
-.. autoclass:: ArcThrough
+.. autoclass:: ArcCentered
 
 	.. autoproperty:: center
 	
@@ -98,9 +98,9 @@ Primitives types
 	
 	.. automethod:: tangent
 	
-	.. image:: /screenshots/primitives-arcthrough.png
-	
-.. autoclass:: Circle
+	.. image:: /screenshots/primitives-arccentered.png
+
+.. autoclass:: ArcThrough
 
 	.. autoproperty:: center
 	
@@ -110,7 +110,7 @@ Primitives types
 	
 	.. automethod:: tangent
 	
-	.. image:: /screenshots/primitives-circle.png
+	.. image:: /screenshots/primitives-arcthrough.png
 
 .. autoclass:: ArcTangent
 
@@ -124,6 +124,12 @@ Primitives types
 	
 	.. image:: /screenshots/primitives-arctangent.png
 	
+.. autoclass:: Ellipsis
+
+	.. autoproperty:: axis
+	
+	.. image:: /screenshots/primitives-ellipsis.png
+	
 .. autoclass:: TangentEllipsis
 
 	.. autoproperty:: center
diff --git a/examples/birfield.py b/examples/birfield.py
index 9aa7749d..d02876e0 100644
--- a/examples/birfield.py
+++ b/examples/birfield.py
@@ -1,5 +1,5 @@
 from madcad import *
-settings.primitives['curve_resolution'] = ('rad', 0.2)
+settings.resolution = ('rad', 0.2)
 
 nballs = 6
 rball = 6/2
diff --git a/examples/compound-planetary.py b/examples/compound-planetary.py
index b4c781d6..62ba9e14 100644
--- a/examples/compound-planetary.py
+++ b/examples/compound-planetary.py
@@ -42,8 +42,8 @@ def spurgear(step, teeth, height, **kwargs):
 
 color_gear = vec3(0.2, 0.3, 0.4)
 
-#settings.primitives['curve_resolution'] = ('sqradm', 0.4)
-settings.primitives['curve_resolution'] = ('sqradm', 0.8)
+#settings.resolution = ('sqradm', 0.4)
+settings.resolution = ('sqradm', 0.8)
 
 ## determine teeth number targeting the desired ratio
 #target = 1/160
diff --git a/examples/differential-asymetric.py b/examples/differential-asymetric.py
index 3b076c5c..ee2a406f 100644
--- a/examples/differential-asymetric.py
+++ b/examples/differential-asymetric.py
@@ -38,7 +38,7 @@ def bolt(a, b, dscrew, washera=False, washerb=False):
 
 		
 
-settings.primitives['curve_resolution'] = ('sqradm', 0.5)
+settings.resolution = ('sqradm', 0.5)
 
 transmiter_angle = pi/6
 transmiter_z = 8
diff --git a/examples/differential-symetric.py b/examples/differential-symetric.py
index 059118a7..1292e014 100644
--- a/examples/differential-symetric.py
+++ b/examples/differential-symetric.py
@@ -31,9 +31,9 @@ def bolt(a, b, dscrew, washera=False, washerb=False):
 			)
 
 # the discretisation paremeter can be set high for exportation, or small for quick computations
-#settings.primitives['curve_resolution'] = ('rad', 0.105)
-#settings.primitives['curve_resolution'] = ('rad', 0.19456)
-settings.primitives['curve_resolution'] = ('sqradm', 0.5)
+#settings.resolution = ('rad', 0.105)
+#settings.resolution = ('rad', 0.19456)
+settings.resolution = ('sqradm', 0.5)
 
 # parameters of the mechanism to design
 transmiter_angle = pi/6
diff --git a/examples/double-universal-joint.py b/examples/double-universal-joint.py
index afc9f384..8011b616 100644
--- a/examples/double-universal-joint.py
+++ b/examples/double-universal-joint.py
@@ -1,7 +1,7 @@
 from madcad import *
 from madcad.joints import *
 from itertools import accumulate
-settings.primitives['curve_resolution'] = ('rad', 0.1)
+settings.resolution = ('rad', 0.1)
 
 # profile separating the bottom and top part allowing them to move around each other and using the maximum volume for the part robustness
 def cardan_sphereprofile(maxangle=0.5):
diff --git a/examples/elliptic-gearbox.py b/examples/elliptic-gearbox.py
index cdc99a59..b481cd1a 100644
--- a/examples/elliptic-gearbox.py
+++ b/examples/elliptic-gearbox.py
@@ -3,9 +3,9 @@
 from madcad.joints import *
 from functools import reduce
 import operator
-#settings.primitives['curve_resolution'] = ('rad', 0.2)
-#settings.primitives['curve_resolution'] = ('sqradm', 0.2)
-settings.primitives['curve_resolution'] = ('sqradm', 0.8)
+#settings.resolution = ('rad', 0.2)
+#settings.resolution = ('sqradm', 0.2)
+settings.resolution = ('sqradm', 0.8)
 
 def ellipsis_perimeter(a, b):
 	return Circle(Axis(O,Z), a).mesh(resolution=('div', 128)).transform(scaledir(X, b/a)).length()
diff --git a/examples/universal-joint.py b/examples/universal-joint.py
index 1f0a2807..2c1afc27 100644
--- a/examples/universal-joint.py
+++ b/examples/universal-joint.py
@@ -1,7 +1,7 @@
 from madcad import *
 from madcad.joints import *
 from itertools import accumulate
-settings.primitives['curve_resolution'] = ('rad', 0.1)
+settings.resolution = ('rad', 0.1)
 
 # profile separating the bottom and top part allowing them to move around each other and using the maximum volume for the part robustness
 def cardan_sphereprofile(maxangle=0.5):
diff --git a/madcad/displays.py b/madcad/displays.py
index 7bdfecee..47f3a812 100644
--- a/madcad/displays.py
+++ b/madcad/displays.py
@@ -32,7 +32,7 @@ def __init__(self, scene, position, size=10, color=None):
 		self.position = fvec3(position)
 		self.size = size
 		self.selected = False
-		self.color = fvec3(color or settings.display['line_color'])
+		self.color = fvec3(color or settings.colors['line'])
 		
 		def load(scene):
 			img = Image.open(resourcedir+'/textures/point.png')
@@ -98,7 +98,7 @@ def __init__(self, scene, axis, interval=None, color=None, pose=fmat4(1)):
 		self.origin = fvec3(axis[0])
 		self.direction = fvec3(axis[1])
 		self.interval = interval
-		self.color = fvec3(color or settings.display['line_color'])
+		self.color = fvec3(color or settings.colors['line'])
 		self.selected = False
 		self.box = Box(center=self.origin, width=fvec3(0))
 		
@@ -162,7 +162,7 @@ def npboundingbox(points):
 
 class AnnotationDisplay(Display):
 	def __init__(self, scene, points, color):
-		self.color = fvec3(color or settings.display['annotation_color'])
+		self.color = fvec3(color or settings.color['annotation'])
 		self.selected = False
 		self.box = npboundingbox(points)
 		# load shader
@@ -248,12 +248,11 @@ def __init__(self, scene, positions, normals, faces, lines, idents, color=None):
 		self.box = npboundingbox(positions)
 		self.options = scene.options
 		
-		s = settings.display
-		color = fvec3(color or s['solid_color'])
-		line = (	(length(s['line_color']) + dot(color-s['solid_color'], s['line_color']-s['solid_color']))
+		color = fvec3(color or settings.colors['surface'])
+		line = (	(length(settings.colors['line']) + dot(color-settings.colors['surface'], settings.colors['line']-settings.colors['surface']))
 					* normalize(color + 1e-6)  )
 		#if length(s['line_color']) > length(color)
-		reflect = normalize(color + 1e-6) * s['solid_reflectivity']
+		reflect = normalize(color + 1e-6) * settings.display['solid_reflectivity']
 		
 		self.vertices = Vertices(scene.ctx, positions, idents)
 		self.disp_faces = FacesDisplay(scene, self.vertices, normals, faces, color=color, reflect=reflect, layer=0)
@@ -300,7 +299,7 @@ class WebDisplay(Display):
 	def __init__(self, scene, positions, lines, points, idents, color=None):
 		self.box = npboundingbox(positions)
 		self.options = scene.options
-		color = color or settings.display['line_color']
+		color = color or settings.colors['line']
 		self.vertices = Vertices(scene.ctx, positions, idents)
 		self.disp_edges = LinesDisplay(scene, self.vertices, lines, color=color, alpha=1, layer=-2e-6)
 		self.disp_groups = PointsDisplay(scene, self.vertices, points, layer=-3e-6)
@@ -556,7 +555,7 @@ def identify(self, view):
 		
 class PointsDisplay:
 	def __init__(self, scene, vertices, indices=None, color=None, ptsize=3, layer=0):
-		self.color = fvec4(color or settings.display['point_color'], 1)
+		self.color = fvec4(color or settings.colors['point'], 1)
 		self.select_color = fvec4(settings.display['select_color_line'], 1)
 		self.ptsize = ptsize
 		self.layer = layer
@@ -643,7 +642,7 @@ def load(scene):
 		self.shader, self.va = scene.resource('viewgrid', load)
 		self.unit = unit
 		self.center = fvec3(center or 0)
-		self.color = fvec4(color) if color else fvec4(settings.display['point_color'],1)
+		self.color = fvec4(color) if color else fvec4(settings.colors['point'],1)
 		self.contrast = contrast
 	
 	def render(self, view):
@@ -670,8 +669,8 @@ def stack(self, scene):
 class SplineDisplay(Display):
 	''' display for spline curve, with handles around'''
 	def __init__(self, scene, handles, curve, color=None):
-		self.color = color or fvec4(settings.display['line_color'], 1)
-		self.color_handles = fvec4(settings.display['annotation_color'], 0.6)
+		self.color = color or fvec4(settings.colors['line'], 1)
+		self.color_handles = fvec4(settings.color['annotation'], 0.6)
 		self.box = npboundingbox(handles)
 		ctx = scene.ctx
 		self.vb_handles = ctx.buffer(handles)
diff --git a/madcad/gear.py b/madcad/gear.py
index 5d886a77..39d07098 100644
--- a/madcad/gear.py
+++ b/madcad/gear.py
@@ -53,8 +53,6 @@
 
 
 
-color_gear = vec3(0.2, 0.3, 0.4)
-
 
 def rackprofile(step, height=None, offset=0, asymetry=None, alpha=radians(20), resolution=None) -> Wire:
 	''' Generate a 1-period tooth profile for a rack
@@ -848,7 +846,7 @@ def samecircle(c1, c2):
 		mesh = exterior + top + bottom + hub
 	else:
 		mesh = exterior + top + structure + bottom + hub
-	return mesh.finish()
+	return mesh.finish() .option(color=settings.colors['gear'])
 
 @cachefunc
 def gear(
@@ -1328,7 +1326,7 @@ def straight_bevel_gear(
 	t_max = acos(cos(gamma_f) / cos_b) / sin_b
 	middle_tooth = 0.5 * (involute(t_max, 0) + involute(-t_max, phase_diff))
 	phase = anglebt(X, middle_tooth * v)
-	return all_teeth.transform(angleAxis(-phase, Z))
+	return all_teeth.transform(angleAxis(-phase, Z)) .option(color=settings.colors['gear'])
 
 def helical_bevel_gear(
 	step:float,
@@ -1487,7 +1485,7 @@ def get_body_points(rho, z, angle):
 	involute = lambda t, t0: spherical_involute(gamma_b, t0, t)
 	t_max = acos(cos(gamma_f) / cos_b) / sin_b
 	middle_tooth = 0.5 * (involute(t_max, 0) + involute(-t_max, phase_diff))
-	return all_teeth.transform(quat(X, middle_tooth * v))
+	return all_teeth.transform(quat(X, middle_tooth * v)) .option(color=settings.colors['gear'])
 
 def _get_intersection(A: vec3, B: vec3, C: vec3, D: vec3) -> float:
 	"""
@@ -1530,7 +1528,7 @@ def _get_intersection(A: vec3, B: vec3, C: vec3, D: vec3) -> float:
 def matrix4placement(z:int, shaft_angle:float) -> mat4x4:
 	"""
 	Return a matrix of transformation given initial state (Z is the initial axis of revolution).
-	This matrix is helpful when you want to place filet gears.
+	This matrix is helpful when you want to place bevel gears.
 
 	Parameters:
 
diff --git a/madcad/kinematic/displays.py b/madcad/kinematic/displays.py
index 3c971841..1200849a 100644
--- a/madcad/kinematic/displays.py
+++ b/madcad/kinematic/displays.py
@@ -583,7 +583,7 @@ def __call__(self, view):
 	
 def kinematic_toolcenter(toolcenter):
 	''' create a scheme for drawing the toolcenter in kinematic manipulation '''
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	angle = 2
 	radius = 60
 	size = 3
@@ -635,10 +635,10 @@ def kinematic_scheme(joints) -> '(Scheme, index)':
 	
 	return scheme, {v: k  for k, v in index.items()}
 
-kinematic_color_names = ['annotation_color', 'schematics_color']
+kinematic_color_names = ['annotation', 'schematic']
 def kinematic_color(i):
 	''' return the scheme color vector for solid `i` in a kinematic '''
-	return fvec4(settings.display[kinematic_color_names[i%2]], 1)
+	return fvec4(settings.colors[kinematic_color_names[i%2]], 1)
 
 
 
diff --git a/madcad/primitives.py b/madcad/primitives.py
index 86f8c8ac..05cbe90f 100644
--- a/madcad/primitives.py
+++ b/madcad/primitives.py
@@ -27,7 +27,7 @@ def fit(self) -> err**2 as float:
 		
 		1. Optional argument `resolution` passed to `primitive.mesh()` or to `web()` or `wire()`
 		2. Optional attribute `resolution` of the primitive object
-		3. Value of `settings.primitives['curve_resolution']` at bake time.
+		3. Value of `settings.resolution` at bake time.
 
 	Specification format:
 		
@@ -55,13 +55,16 @@ def isprimitive(obj):
 	''' Return True if obj match the signature for primitives '''
 	return hasattr(obj, 'mesh') and hasattr(obj, 'slvvars')
 
+# aliases, for those who like them
 Vector = Point = vec3
 
 
 class Axis(object):
 	''' Mimic the behavior of a tuple, but with the primitive signature. '''
 	__slots__ = ('origin', 'direction', 'interval')
-	def __init__(self, origin, direction, interval=None):
+	def __init__(self, origin, direction=None, interval=None):
+		if direction is None:
+			origin, direction = vec3(0), origin
 		self.origin, self.direction = origin, direction
 		self.interval = interval
 	
diff --git a/madcad/scheme.py b/madcad/scheme.py
index fa50e032..33e1246a 100644
--- a/madcad/scheme.py
+++ b/madcad/scheme.py
@@ -86,7 +86,7 @@ def __init__(self, vertices=None, spaces=None, primitives=None, **kwargs):
 		self.primitives = primitives or {} # list of indices for each shader
 		self.components = []	# displayables associated to spaces
 		# for creation: last vertex inserted
-		self.current = {'color':fvec4(settings.display['annotation_color'],1), 'flags':0, 'layer':0, 'space':world, 'shader':'line', 'track':0, 'normal':fvec3(0)}
+		self.current = {'color':fvec4(settings.colors['annotation'],1), 'flags':0, 'layer':0, 'space':world, 'shader':'line', 'track':0, 'normal':fvec3(0)}
 		self.continuous = False
 		self.set(**kwargs)
 		
@@ -558,7 +558,7 @@ def mesh_placement(mesh) -> '(pos,normal)':
 
 def note_floating(position, text, align=(0,0)):
 	''' place a floating note at given position '''
-	return Displayable(TextDisplay, position, text, align=align, color=settings.display['annotation_color'], size=settings.display['view_font_size'])
+	return Displayable(TextDisplay, position, text, align=align, color=settings.colors['annotation'], size=settings.display['view_font_size'])
 
 
 def note_leading(placement, offset=None, text='here'):
@@ -574,7 +574,7 @@ def note_leading(placement, offset=None, text='here'):
 	elif not isinstance(offset, vec3):
 		raise TypeError('offset must be scalar or vector')
 	
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	sch = Scheme(color=fvec4(color,0.7))
 	sch.add([origin, origin+offset], shader='line', space=world)
 	x,y,z = dirbase(normalize(vec3(offset)))
@@ -607,7 +607,7 @@ def note_distance(a, b, offset=0, project=None, d=None, tol=None, text=None, sid
 		elif tol:               text = '{d:.4g}  ± {tol}'
 		else:                   text = '{d:.4g}'
 	text = text.format(d=d, tol=tol)
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	# convert input vectors
 	x = dirbase(project, b-a)[0]
 	z = project if side else -project
@@ -699,7 +699,7 @@ def note_angle(a0, a1, offset=0, d=None, tol=None, text=None, unit='deg', side=F
 		elif tol:               text = '{d:.4g}{unit}  ± {tol}'
 		else:                   text = '{d:.4g}{unit}'
 	text = text.format(d=d, tol=tol, unit=unit)
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	# arc center
 	if o1 == o0:	center = o0
 	else:			center = o0 + unproject(project(o1-o0, x1), d0)
@@ -766,7 +766,7 @@ def note_radius(mesh, offset=None, d=None, tol=None, text=None, propagate=2):
 	
 	arrowplace = place + noproject(offset, normal)
 	note = note_leading((arrowplace,normal), offset=project(offset, normal), text=text or 'R {:.4g}'.format(radius))
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	note.set(shader='line', layer=1e-4, color=fvec4(color,0.3), space=world)
 	note.add([place, arrowplace])
 	return note
@@ -1039,7 +1039,7 @@ def note_label(placement, offset=None, text='!', style='rect'):
 	elif not isinstance(offset, vec3):
 		raise TypeError('offset must be scalar or vector')
 	
-	color = settings.display['annotation_color']
+	color = settings.colors['annotation']
 	x,_,z = dirbase(normalize(offset))
 	sch = Scheme()
 	sch.set(color=fvec4(color,0.7))
@@ -1081,7 +1081,7 @@ def note_iso(p, offset, type, text, refs=(), label=None):
 	#scheme = None
 	
 	#def __init__(self, scene, matrix, color=None):
-		#if not color:	color = settings.display['annotation_color']
+		#if not color:	color = settings.colors['annotation']
 		
 		#if not self.scheme:
 			#type(self).scheme = sch = Scheme(layer=1e-4)
@@ -1115,7 +1115,7 @@ def note_iso(p, offset, type, text, refs=(), label=None):
 		#yield from self.disp.stack(scene)
 		
 def note_base(matrix, color=None, labels=('X', 'Y', 'Z'), name=None, size=0.4):
-	if not color:	color = settings.display['annotation_color']
+	if not color:	color = settings.colors['annotation']
 	if not name:	name = ''
 	if not labels:	labels = [None]*3
 	
@@ -1155,7 +1155,7 @@ def note_base(matrix, color=None, labels=('X', 'Y', 'Z'), name=None, size=0.4):
 	return sch
 	
 def note_rotation(quaternion, color=None, size=0.4):
-	if not color:	color = settings.display['annotation_color']
+	if not color:	color = settings.colors['annotation']
 	
 	direction = vec3(glm.axis(quaternion))
 	angle = glm.angle(quaternion)
diff --git a/madcad/settings.py b/madcad/settings.py
index caf5fbba..02b68d17 100644
--- a/madcad/settings.py
+++ b/madcad/settings.py
@@ -12,9 +12,9 @@
 import sys, os, yaml
 from os.path import dirname, exists
 
-
+# settings for all Display objects and for the scene rendering
 display = {
-	'field_of_view': pi/6,
+	'field_of_view': pi/6,  # camera field of view for scene views
 	'view_font_size': 8,  # font size for annotations
 	'joint_size': 50, # maximum pixel size of joints
 	'sharp_angle': pi/6, # above this threshold angles between mesh triangles are considered sharp, below they are rendered softened
@@ -24,20 +24,47 @@
 	'select_color_line': fvec3(0.5, 1, 0.6), # color for selected lines
 	'highlight_color': fvec3(0.1, 0.2, 0.2),
 	
-	'solid_color': fvec3(0.2, 0.2, 0.2),  # surface color of meshes
 	'solid_color_front': 1., # surface intensity for portions of surface parallel to the view direction
 	'solid_color_side': 0.2, # surface intensity for portions of surface orthogonal to the view direction
 	'solid_reflectivity': 4, # intensity of surface reflections
 	'solid_reflect': 'skybox-white.png', # skybox texture for reflects
-	'line_color': fvec3(0.9, 0.9, 0.9),  # wire color
-	'point_color': fvec3(0.9, 0.9, 0.9),  # points color
-	'schematics_color': fvec3(0.3, 0.8, 1),
 	'line_width': 1.0, # pixel width of edges, may work or not depending on openGL implementation
-	'annotation_color': fvec3(0.2, 0.7, 1),
 	
 	'system_theme': True, # adapt madcad colors to the current desktop theme
 	}
 
+# theme colors for objects in the scene
+colors = {
+	# display elements
+	
+	# mesh surface
+	'surface': fvec3(0.2, 0.2, 0.2),
+	# mesh and primitives lines
+	'line': fvec3(0.9, 0.9, 0.9),
+	# mesh and primitives points
+	'point': fvec3(0.9, 0.9, 0.9),
+	# annotations like dimensions and constraints
+	'annotation': fvec3(0.2, 0.7, 1),
+	# schematics like kinematic schemes
+	'schematic': fvec3(0.3, 0.8, 1),
+	
+	# color for standard parts
+	
+	# screws and nults
+	'bolt': fvec3(0.2),
+	# gears and transmission parts
+	'gear': fvec3(0.2, 0.3, 0.4),
+	# bearing and guiding parts
+	'bearing': fvec3(0.5,0.4,0.35),
+	'bearing_cage': fvec3(0.3,0.2,0),
+	# deformable parts like springs
+	'spring': fvec3(0.2),
+	# circulating elements like balls in bearings
+	'circulating': fvec3(0,0.1,0.2),
+	}
+
+# initial settings for a scene, each scene will duplicate this and will be able to modify them at runtime
+# this dictionnary represent the initial settings of the user
 scene = {
 	'projection': 'Perspective',
 	
@@ -62,9 +89,8 @@
 	'snap_dist': 10,	# pixel distance to click items
 	}
 
-primitives = {
-	'curve_resolution': ['rad', pi/16],	# angle maximal pour discretisation des courbes
-	}
+resolution = ['rad', pi/16]  # maximum angle for discretizing curves, see `curve_resolution()`
+
 
 # get configuration directory depending on OS
 if sys.platform == 'win32':
@@ -75,7 +101,7 @@
 	configdir = home+'/.config'
 
 config = configdir+'/madcad/pymadcad.yaml'
-settings = {'display':display, 'scene':scene, 'controls':controls, 'primitives':primitives}
+settings = {'display':display, 'scene':scene, 'controls':controls, 'resolution':resolution}
 
 
 def install():
@@ -121,7 +147,7 @@ def curve_resolution(length, angle, param=None):
 		:length:  is the curvilign length of the curve
 		:angle:   is the integral of the absolute curvature (total rotation angle)
 	'''
-	kind, prec = param or primitives['curve_resolution']
+	kind, prec = param or resolution
 	if kind == 'div':
 		res = prec
 	elif kind == 'm':
@@ -162,11 +188,13 @@ def qtc(role):
 		'background_color': qtc(palette.Base),
 		'select_color_face': selection * 0.05,
 		'select_color_line': selection * 1.1,
-		'line_color': qtc(palette.Text),
-		'point_color': qtc(palette.Text),
-		'solid_color': mix(qtc(palette.Text), qtc(palette.Window), 0.7),
-		'schematics_color': mix(qtc(palette.Text)*normalize(qtc(palette.LinkVisited)+0.01), qtc(palette.LinkVisited), 0.5),
-		'annotation_color': mix(qtc(palette.Text)*normalize(qtc(palette.Link)+0.01), qtc(palette.Link), 0.5),
+		})
+	colors.update({
+		'line': qtc(palette.Text),
+		'point': qtc(palette.Text),
+		'surface': mix(qtc(palette.Text), qtc(palette.Window), 0.7),
+		'schematic': mix(qtc(palette.Text)*normalize(qtc(palette.LinkVisited)+0.01), qtc(palette.LinkVisited), 0.5),
+		'annotation': mix(qtc(palette.Text)*normalize(qtc(palette.Link)+0.01), qtc(palette.Link), 0.5),
 		})
 
 
diff --git a/madcad/standard.py b/madcad/standard.py
index 1a845b62..161b0039 100644
--- a/madcad/standard.py
+++ b/madcad/standard.py
@@ -99,8 +99,6 @@ def stceil(x, precision=0.1):
 
 # --------- screw stuff -----------------------
 	
-bolt_color = vec3(0.2)
-	
 @cachefunc
 def screw(d, length, filet_length=None, head='SH', drive=None, detail=False):
 	''' Create a standard screw using the given drive and head shapes
@@ -155,7 +153,7 @@ def screw(d, length, filet_length=None, head='SH', drive=None, detail=False):
 					vec3(r*0.8, 0, -length),
 					vec3(0, 0, -length),
 					]) .segmented())
-	screw = (body + head).finish().option(color=bolt_color)
+	screw = (body + head).finish().option(color=settings.colors['bolt'])
 	return Solid(part=screw, axis=axis)
 
 def screwdrive_torx(d):
@@ -376,7 +374,7 @@ def hexnut(d, w, h):
 	nut = intersection(base, ext)
 	chamfer(nut, nut.frontiers(4,5) + nut.frontiers(0,5), width=d*0.1)
 
-	nut.finish().option(color=bolt_color)
+	nut.finish().option(color=settings.colors['bolt'])
 	return Solid(
 				part=nut, 
 				bottom=Axis(-0.5*h*Z, -Z, interval=(0,h)), 
@@ -449,7 +447,7 @@ def washer(d, e=None, h=None) -> Mesh:
 		if h is None:	h = d*0.1
 	
 	return Solid(
-				part=thicken(revolution(web([e/2*X, d/2*X])), h).option(color=bolt_color), 
+				part=thicken(revolution(web([e/2*X, d/2*X])), h).option(color=settings.colors['bolt']), 
 				top=Axis(h*Z, Z, interval=(0,h)), 
 				bottom=Axis(O, -Z, interval=(0,h)),
 				)
@@ -910,10 +908,6 @@ def bearing_spec(code):
 	elif re.match(r'[\d\.]+x[\d\.]+x[\d\.]+', code):
 		return tuple(float(d) for d in re.split('x'))
 		
-bearing_color = vec3(0.5,0.4,0.35)
-bearing_cage_color = vec3(0.3,0.2,0)
-bearing_circulating_color = vec3(0,0.1,0.2)
-		
 		
 def bearing_ball(dint, dext=None, h=None, sealing=False, detail=False) -> Solid:
 	# convenient variables
@@ -950,7 +944,7 @@ def bearing_ball(dint, dext=None, h=None, sealing=False, detail=False) -> Solid:
 		exterior += wire(ArcCentered((rb*X,-Y), vec3(rext-e, 0, -hr), vec3(rext-e, 0, hr)))
 		interior.close()
 		exterior.close()
-		part = revolution(web([exterior, interior]), axis) .option(color=bearing_color)
+		part = revolution(web([exterior, interior]), axis) .option(color=settings.colors['bearing'])
 
 		nb = int(0.7 * pi*rb/rr)	# number of balls that can fit in
 		balls = repeat(icosphere(rb*X, rr), nb, angleAxis(radians(360)/nb, Z)) .option(color=vec3(0,0.1,0.2))
@@ -973,7 +967,7 @@ def bearing_ball(dint, dext=None, h=None, sealing=False, detail=False) -> Solid:
 
 		cage = thicken(
 				surf + surf.transform(mat3(1,1,-1)) .flip(), 
-				c) .option(color=bearing_cage_color)
+				c) .option(color=settings.colors['bearing_cage'])
 				
 		# asemble
 		return Solid(part=part, cage=cage, balls=balls, axis=axis)
@@ -995,7 +989,7 @@ def bearing_ball(dint, dext=None, h=None, sealing=False, detail=False) -> Solid:
 			)
 		return Solid(
 				part=revolution(web([exterior, interior]), axis)
-						.option(color=bearing_color), 
+						.option(color=settings.colors['bearing']), 
 				axis=axis)
 
 
@@ -1071,7 +1065,7 @@ def bearing_roller(dint, dext=None, h=None, contact=0, hint=None, hext=None, det
 		part = revolution(web([
 					exterior, 
 					interior,
-					]).flip(), axis) .option(color=bearing_color)
+					]).flip(), axis) .option(color=settings.colors['bearing'])
 	
 		# create conic rollers
 		roller = revolution(Segment(mix(p1,p3,0.05), mix(p3,p1,0.05)), angled)
@@ -1083,7 +1077,7 @@ def bearing_roller(dint, dext=None, h=None, contact=0, hint=None, hext=None, det
 		# number of rollers that can fit in
 		nb = int(pi*(rint+rext) / (2.5*distance_pa(p1,angled)))
 		rollers = repeat(roller, nb, rotatearound(2*pi/nb, axis)) 
-		rollers.option(color=bearing_circulating_color)
+		rollers.option(color=settings.colors['circulating'])
 
 		# roller cage
 		p6 = mix(p4,p3,0.6) - e*angled[1]
@@ -1095,7 +1089,7 @@ def bearing_roller(dint, dext=None, h=None, contact=0, hint=None, hext=None, det
 		filet(cage_profile, [1], radius=c)
 		cage = revolution(cage_profile, axis)
 		cage = pierce(cage, inflate(rollers, 0.5*c), False)
-		cage = thicken(cage, c) .option(color=bearing_cage_color)
+		cage = thicken(cage, c) .option(color=settings.colors['bearing_cage'])
 		
 		# assemble
 		return Solid(part=part, cage=cage, rollers=rollers, axis=axis)
@@ -1107,7 +1101,7 @@ def bearing_roller(dint, dext=None, h=None, contact=0, hint=None, hext=None, det
 				part=revolution(
 					(exterior + interior) .close() .flip(),
 					axis,
-					) .option(color=bearing_color), 
+					) .option(color=settings.colors['bearing']), 
 				axis=axis)
 		
 
@@ -1147,12 +1141,12 @@ def bearing_thrust(dint, dext, h, detail=False) -> Solid:
 		bot += wire(ArcCentered((rb*X,-Y), vec3(rb-hr, 0, -w+e), vec3(rb+hr, 0, -w+e)))
 		top.close()
 		bot.close()
-		part = revolution(web([top, bot]), axis) .option(color=bearing_color)
+		part = revolution(web([top, bot]), axis) .option(color=settings.colors['bearing'])
 		
 		# number of balls to place
 		nb = int(0.8 * pi*rb/rr)
 		balls = repeat(icosphere(rb*X, rr), nb, angleAxis(radians(360)/nb, Z))
-		balls.option(color=bearing_circulating_color)
+		balls.option(color=settings.colors['circulating'])
 		
 		# cage
 		cage_profile = Wire([ 
@@ -1165,7 +1159,7 @@ def bearing_thrust(dint, dext, h, detail=False) -> Solid:
 		
 		cage_surf = revolution(cage_profile, axis)
 		cage_surf = pierce(cage_surf, inflate(balls, 0.2*c), False)
-		cage = thicken(cage_surf, c) .option(color=bearing_cage_color)
+		cage = thicken(cage_surf, c) .option(color=settings.colors['bearing_cage'])
 		
 		# assemble
 		return Solid(part=part, cage=cage, balls=balls, axis=axis)
@@ -1187,7 +1181,7 @@ def bearing_thrust(dint, dext, h, detail=False) -> Solid:
 			)
 
 		return Solid(
-				part=revolution(web([top, bot]), axis) .option(color=bearing_color), 
+				part=revolution(web([top, bot]), axis) .option(color=settings.colors['bearing']), 
 				axis=axis)
 
 	
@@ -1231,7 +1225,7 @@ def slidebearing(dint, h=None, thickness=None, shoulder=None, opened=False) -> S
 	axis = Axis(O,Z, interval=(-h,0))
 	shape = revolution(profile, axis, 1.98*pi if opened else 2*pi)
 	
-	part = thicken(shape, thickness) .option(color=bearing_color)
+	part = thicken(shape, thickness) .option(color=settings.colors['bearing'])
 	line = (  select(part, vec3(-rint,0,-h), stopangle(pi/2))
 			+ select(part, vec3(dint,dint,-h), stopangle(pi/2))
 			)
diff --git a/tests/test_bevelgear.py b/tests/test_bevelgear.py
index 5a9b2fe8..423496ff 100644
--- a/tests/test_bevelgear.py
+++ b/tests/test_bevelgear.py
@@ -1,10 +1,9 @@
 #!/usr/bin/python3
 from madcad.gear import *
-from madcad.mesh import edgekey, facekeyo
 from madcad.kinematic import Solid
 from madcad import settings
 
-settings.primitives['curve_resolution'] = ('rad', 0.1)
+settings.resolution = ('rad', 0.1)
 
 # Colors
 class bcolors:
diff --git a/tests/test_gear.py b/tests/test_gear.py
index 4967725d..dc8a0d36 100644
--- a/tests/test_gear.py
+++ b/tests/test_gear.py
@@ -1,9 +1,8 @@
 from madcad.gear import *
-from madcad.mesh import edgekey, facekeyo
 from madcad.kinematic import Solid
 
 import madcad
-madcad.settings.primitives['curve_resolution'] = ('rad', 0.1)
+madcad.settings.resolution = ('rad', 0.1)
 
 # Colors
 class bcolors:
diff --git a/tests/test_gearprofile.py b/tests/test_gearprofile.py
index 72c28e5f..c756e95a 100644
--- a/tests/test_gearprofile.py
+++ b/tests/test_gearprofile.py
@@ -1,7 +1,7 @@
 from madcad import *
 from madcad import gear
 
-settings.primitives['curve_resolution'] = ('rad', 0.05)
+settings.resolution = ('rad', 0.05)
 
 axis = (vec3(0),vec3(0,0,1))