#How to cut threads?
11 messages in this thread
I am trying to loft a helix from a triangle shape, and I want the apex of the
triangle to consistently point toward the axis of the helix.
When I loft the helix, the triangle rotates about the path. My objective is
to create a helix that I can use in a Boolean subtraction from a cylinder to
create the effect of machined threads, like on a bolt or screw. Therefore, the
apex of the triangle must consistently point toward the center of the cylinder
to create the threads. How can I do this? What are the settings I should use
in Lofter? Is there an IPAS to create threads?
>> …to consistently point toward the axis of the helix.
Try setting "LOFT-BANKING = OFF" in your 3DS.SET file.
– Dave
THANKS! After I turned "LOFT-BANKING = OFF" the triangle lofted just the way I
wanted it to. Now, I have to figure out how best to combine the lofted helix
with a cylinder. I think it might be easier to manipulate if I loft the
threads with the apex of the triangle pointing outboard, and then combining it
with a cylinder, rather than trying a Boolean Subtraction. Any thou
-JOHN
>> combining it with a cylinder, rather than trying a Boolean Subtraction.
Outward pointing sounds good, and to avoid booleans altogether, you could just
"attach" it.
– Dave
John,
You might wanna try the 'contour' button in the Lofter. It should be
available after selecting 'Objects/Make'. This ensures that whatever the
orientation of your shape to the axis at the start of your path will be
maintained throughout the helix (or SurfRev for that matter…).
See Ya! Kevin
Is there any reason you couldn't create the cross section of the threaded
object in the 2D shaper and then loft the object/threads by rotating the CS
over the length? I think this would produce a much cleaner mesh.
— James — Choreo Motion —
Doing a surf rev would work, except threads are helical, not parallel "rings",
and if you wanted to rotate the object, the parallel rings would not be
accurate.
John,
>> Doing a surf rev would work, except threads are helical, not parallel
>> "rings"
James wasn't talking about doing a surf rev (in AutoCAD?), he was talking about
LOFTING a cross section in a circular motion. I don't see why this wouldn't
work or be accurate. <Correct me if I spoke out of turn, James!)
Bob W.
> Correct me if I spoke out of turn, James! <
Nope. You're exactly right WRT to my meaning. I clarified more in another
response.
— James — Choreo Motion —
Consider this:
Extrude a simplified letter x . Then grab the extrusion and twist it in
opposite directions at each end, like you would a wet towel before snapping it
like a whip. The result is that the indentations of the letter x cause a
helical groove to be produced.
This same effect can be used in the Shaper and Lofter by creating a gear-like
shape in the 2D shaper and then using the deform/twist or shape/rotate in the
3D lofter. If this is still unclear I can send you an example file.
BTW, ever seen a drill bit snapped in half? The CS looks somewhat like a
capital S.
— James — Choreo Motion —
I've uploaded an example of an entirely lofted bolt to the libs (Bolt.Zip). It
should be available shortly. Pay close attention to the Deform/Twist and
Deform/Scale settings in the Lofter. The resulting mesh could be optimized by
adjusting path steps and shape steps in the lofter.
Also note that the example bolt is double-threaded. To create a
single-threaded bolt, you'll need to make that ellipse into a half-circle on
one side and a half-ellipse on the other.
— James — Choreo Motion —