Package Docs 0.8.17

class taperable_helix.HelixLocation(radius=None, horz_offset=0, vert_offset=0)

radius: Optional[float] = None

radius of helix if none h.radius

horz_offset: float = 0

horizontal offset added to radius then x and y calculated

vert_offset: float = 0

vertical added to z of radius

class taperable_helix.Helix(radius, pitch, height, taper_out_rpos=0, taper_in_rpos=1, inset_offset=0, first_t=0, last_t=1)

This class represents a taperable Helix.

The required attributes are radius, pitch and height. Thse attributes create simple single line helix. But the primary purpose for Helix is to create a set of helical “wires” using non-zero values for taper_rpos, horz_offset and vert_offset to define solid helixes that can taper at each end to a point.

This is useful for creating internal and external threads for nuts and bolts. This is accomplished by invoking helix() multiple times with same radius, pitch, taper_rpos, inset_offset, first_t, and last_t. But with different HelixLocation radius, horz_offset and vert_offset.

Each returned function will then generate a helix defining an edge of the thread. The edges can be used to make faces and subsequently a solid of the thread. This can then be combined with the “core” objects which the threads are “attached” using a “union” operator.

radius: float

radius of the basic helix.

pitch: float

pitch of the helix per revolution. I.e the distance between the height of a single “turn” of the helix.

height: float

height of the cyclinder containing the helix.

taper_out_rpos: float = 0

taper_out_rpos is a decimal number with an inclusive range of 0..1 such that (taper_out_rpos * t_range) defines the t value where tapering out ends, it begins at t == first_t. A ValueError exception is raised if taper_out_rpos < 0 or > 1 or taper_out_rpos > taper_in_rpos. Default is 0 which is no out taper.

taper_in_rpos: float = 1

taper_in_rpos: is a decimal number with an inclusive range of 0..1 such that (taper_in_rpos * t_range) defines the t value where tapering in begins, it ends at t == last_t. A ValueError exception is raised if taper_out_rpos < 0 or > 1 or taper_out_rpos > taper_in_rpos. Default is 1 which is no in taper.

inset_offset: float = 0

inset_offset: the helix will start at z = inset_offset and will end at z = height - (2 * inset_offset). Default 0.

first_t: float = 0

first_t is the first t value passed to the returned function. Default 0

last_t: float = 1

last_t is the last t value passed to the returned function. Default 1

helix(hl=None)

This function returns a Function that is used to generates points on a helix.

It takes an optional HelixLocation which refines the location of the final helix when its tapered. If HelixLocation is None then the radius is Helix.radius and horz_offset and vert_offset will be 0. If its not None HelixLocation.radius maybe None, in which case Helix.radius will be used. and HelixLocation.horz_offset will be added to the radius and used to calculate x and y. The HelixLocation.vert_offset will be added to z.

This function returns a function, f. The funciton f that takes one parameter, an inclusive value between first_t and last_t. We then define t_range=last_t-first_t and the rel_height=(last_t-t)/t_range. The rel_height is the relative position along the “z-axis” which is used to calculate function functions returned tuple(x, y, z) for a point on the helix.

Credit: Adam Urbanczyk from cadquery [forum post](https://groups.google.com/g/cadquery/c/5kVRpECcxAU/m/7no7_ja6AAAJ)

Parameters

hl (Optional[HelixLocation]) – Defines a refinded location when the helix is tapered

Return type

Callable[[float], Tuple[float, float, float]]

Returns

A function which is passed “t”, an inclusive value between first_t and last_t and returns a 3D point (x, y, z) on the helix as a function of t.