#! /usr/bin/env python

# -*- coding: utf-8 -*-

from __future__ import division

import os

import sys

import re

# Assumes SolidPython is in site-packages or elsewhwere in sys.path

from solid import *

from solid.utils import *

SEGMENTS = 24

# FIXME: ought to be 5

DFM = 5 # Default Material thickness

tab_width = 5

tab_offset = 4

tab_curve_rad = .35

# TODO: Slots & tabs make it kind of difficult to align pieces, since we

# always need the slot piece to overlap the tab piece by a certain amount.

# It might be easier to have the edges NOT overlap at all and then have tabs

# for the slots added programmatically. -ETJ 06 Mar 2013

def t_slot_holes(poly, point=None, edge_vec=RIGHT_VEC, screw_vec=DOWN_VEC, screw_type='m3', screw_length=16, material_thickness=DFM, kerf=0):

'''

Cuts a screw hole and two notches in poly so they'll

interface with the features cut by t_slot()

Returns a copy of poly with holes removed

-- material_thickness is the thickness of the material *that will

be attached** to the t-slot, NOT necessarily the material that poly

will be cut on.

-- screw_vec is the direction the screw through poly will face; normal to poly

-- edge_vec orients the holes to the edge they run parallel to

TODO: add kerf calculations

'''

point = point if point else ORIGIN

point = euclidify(point, Point3)

screw_vec = euclidify(screw_vec, Vector3)

edge_vec = euclidify(edge_vec, Vector3)

src_up = screw_vec.cross(edge_vec)

a_hole = square([tab_width, material_thickness], center=True)

move_hole = tab_offset + tab_width / 2

tab_holes = left(move_hole)(a_hole) + right(move_hole)(a_hole)

# Only valid for m3-m5 screws now

screw_dict = screw_dimensions.get(screw_type.lower())

if screw_dict:

screw_w = screw_dict['screw_outer_diam']

else:

raise ValueError(

"Don't have screw dimensions for requested screw size %s" % screw_type)

# add the screw hole

tab_holes += circle(screw_w / 2) # NOTE: needs any extra space?

tab_holes = transform_to_point(

tab_holes, point, dest_normal=screw_vec, src_normal=UP_VEC, src_up=src_up)

return poly - tab_holes

def t_slot(poly, point=None, screw_vec=DOWN_VEC, face_normal=UP_VEC, screw_type='m3', screw_length=16, material_thickness=DFM, kerf=0):

'''

Cuts a t-shaped shot in poly and adds two tabs

on the outside edge of poly.

Needs to be combined with t_slot_holes() on another

poly to make a valid t-slot connection

-- material_thickness is the thickness of the material *that will

be attached** to the t-slot, NOT necessarily the material that poly

will be cut on.

-- This method will align the t-slots where you tell them to go,

using point, screw_vec (the direction the screw will be inserted), and

face_normal, a vector normal to the face being altered. To avoid confusion,

it's often easiest to work on the XY plane.

TODO: include kerf in calculations

'''

point = point if point else ORIGIN

point = euclidify(point, Point3)

screw_vec = euclidify(screw_vec, Vector3)

face_normal = euclidify(face_normal, Vector3)

tab = tab_poly(material_thickness=material_thickness)

slot = nut_trap_slot(

screw_type, screw_length, material_thickness=material_thickness)

# NOTE: dest_normal & src_normal are the same. This should matter, right?

tab = transform_to_point(

tab, point, dest_normal=face_normal, src_normal=face_normal, src_up=-screw_vec)

slot = transform_to_point(

slot, point, dest_normal=face_normal, src_normal=face_normal, src_up=-screw_vec)

return poly + tab - slot

def tab_poly(material_thickness=DFM):

r = [[tab_width + tab_offset, -EPSILON],

[tab_offset, -EPSILON],

[tab_offset, material_thickness],

[tab_width + tab_offset, material_thickness], ]

l = [[-rp[0], rp[1]] for rp in r]

tab_pts = l + r

tab_faces = [[0, 1, 2, 3], [4, 5, 6, 7]]

tab = polygon(tab_pts, tab_faces)

# Round off the top points so tabs slide in more easily

round_tabs = False

if round_tabs:

points_to_round = [[r[1], r[2], r[3]],

[r[2], r[3], r[0]],

[l[1], l[2], l[3]],

[l[2], l[3], l[0]],

]

tab = fillet_2d(three_point_sets=points_to_round, orig_poly=tab,

fillet_rad=1, remove_material=True)

return tab

def nut_trap_slot(screw_type='m3', screw_length=16, material_thickness=DFM):

# This shape has a couple uses.

# 1) Right angle joint between two pieces of material.

# A bolt goes through the second piece and into the first.

# 2) Set-screw for attaching to motor spindles.

# Bolt goes full length into a sheet of material. Set material_thickness

# to something small (1-2 mm) to make sure there's adequate room to

# tighten onto the shaft

# Only valid for m3-m5 screws now

screw_dict = screw_dimensions.get(screw_type.lower())

if screw_dict:

screw_w = screw_dict['screw_outer_diam']

screw_w2 = screw_w / 2

# NOTE: How are these tolerances?

nut_hole_x = (screw_dict['nut_inner_diam'] + 0.2) / 2

nut_hole_h = screw_dict['nut_thickness'] + 0.5

slot_depth = material_thickness - screw_length - 0.5

# If a nut isn't far enough into the material, the sections

# that hold the nut in may break off. Make sure it's at least

# half a centimeter. More would be better, actually

nut_loc = -5

else:

raise ValueError(

"Don't have screw dimensions for requested screw size %s" % screw_type)

slot_pts = [[screw_w2, EPSILON],

[screw_w2, nut_loc],

[nut_hole_x, nut_loc],

[nut_hole_x, nut_loc - nut_hole_h],

[screw_w2, nut_loc - nut_hole_h],

[screw_w2, slot_depth],

]

# mirror the slot points on the left

slot_pts += [[-x, y] for x, y in slot_pts][-1::-1]

# TODO: round off top corners of slot

# Add circles around t edges to prevent acrylic breakage

slot = polygon(slot_pts)

slot = union()(

slot,

translate([nut_hole_x, nut_loc])(circle(tab_curve_rad)),

translate([-nut_hole_x, nut_loc])(circle(tab_curve_rad))

)

return render()(slot)

def assembly():

a = union()

return a

if __name__ == '__main__':

a = assembly()

scad_render_to_file(a, file_header='$fn = %s;' %

SEGMENTS, include_orig_code=True)