Hi Brian,
you will see from the Autodesk plugin that it
produces facets and I think it then uses the facet
edges to loft thus giving a smooth finish.
I've found given a constant helix and no rotation
you only have to generate enough facets on a small
part of the helix to produce a profile that you can
then sweep to get a screw.
If it was just point contact it's possible to calculate
the profile width from the helix angle bottle width
shaft outer diameter and inner diameter but this
is not what I see in the videos on YouTube.
Cheers
Barry

Hi Barry, also I suppose it would be nice to generate the convex hull between each pair of cutting bottles but unfortunately I don't have anything that would do that.

Also just wanted to make sure you saw the plug-in above, I think we were writing posts at the same time.

- Michael

Here's a demo of using the BottleFeedArray plugin, if you use a lot of stations it can cause problems with the booleans with things just barely grazing each other. I had some better success on denser ones with unioning the bottles together first before differencing them from the main body:









I can imagine that the convex hull between each pair would make for a nicer imprint. That's a lot easier to do on a triangle mesh than on curved solids though.

- Michael

Result must be smoothing of you must have sharp edges inside (each part 's bottle visible) ?

@ Michael
so does it possible to add the Rotation option of the profile inside the native Array Curve Function ?
Now there is only the orientation's rotation of the curve itself! (in the Array curve function)

Hi Michael,
thanks for the script but unfortunately its rotation is in the wrong axis.
Attached is a basic drawing where I have manually rotated a few bottles and
placed them on the helix. You can see from the photo's the facets are cut at
90 degrees to the shaft axis. Also I have shown the result of using the profiles only
and sweep you can see if the profiles where extruded they would cut thro the screw.
The array along curve drawing shows the bottles arrayed at 90 degrees to the shaft but
with no rotation.
Cheers
Barry

This one ?
http://moiscript.weebly.com/uploads/3/9/3/8/3938813/foret.3dm
A simple Sweep

Re Michaels BottleFeedArray script:
I am getting the bottle rotation about the axis of the bottle, but am not getting any rotation of the bottle around the axis of the helix.
- Brian

Hello,

maybe something like that?



Have a nice day
Karsten

>>I recall seeing this subject on the internet before.
A google search of "bottle feed screw design," produces some hits.

That was probably on the Geomagic Design Forums. Can't recall the name of the thread though..

Hi Karsten,
which version of the node editor do I need to run your node.
Can you please post the 3dm you used so I have a start point
for me to understand how it works.
Thanks
Barry

Hello Barry,

I've used nodeeditor v0.93 in the modified version. You don't need a base file for that.
Here is the link:
http://moi3d.com/forum/index.php?webtag=MOI&msg=8197.7

Nevertheless here is the resultfile:

A nice day to all
Karsten

Hi Pilou,

> @ Michael
> so does it possible to add the Rotation option of the profile inside the native Array Curve Function ?
> Now there is only the orientation's rotation of the curve itself! (in the Array curve function)

The rotation option from array curve is referring to rotation around the curve tangent at each point. From what I've understood this special kind of array that Barry needs should only produce rotations in a 2D view and not around the curve tangent.

- Michael

Bemfarmer,

I would look at the "ScriptArray" script Michael made.

http://moi3d.com/forum/index.php?webtag=MOI&msg=5595.18

If you remove the scaling part and then look at adding vertical steps (Like the circle array command), possibly incorporating the "VariablePitchHelix" stuff, it would make a loftable, single smooth surface to subtract, for the screw.

Not that that's "Easy" or something. If anybody can do it, you can!

Hi Barry,

> thanks for the script but unfortunately its rotation is in the wrong axis.

Sorry, I had interpreted one of your images as the rotation needing to happen in the Front view. Or I guess I just happened to position things that way when I made my own file to test with.

You can change the axis by editing line number 107 in the BottleFeedArray.js file.

It currently has this:

	var frame = moi.vectorMath.createFrontFrame();

Change it to this instead:

	var frame = moi.vectorMath.createTopFrame();

Hopefully that will do what you need then.

- Michael

Edit: Changing Frame to Top yielded analogous results to Front version.

With respect, I think that the BottleFeedArray script is not complete, or not correct.
It seems to me that the bottle is sitting on its bottom, sunk into the cylinder.

The bottles should sit vertically, alongside and partially intersecting the screw/cylinder.
The center of the side of the bottle should, more or less, align horizontally with the axis of the cylinder.
The bottles are to be rotated around their vertical axis, as they move to the right.
The cylinder is the blank stock which will become the screw.
In an actual physical model, the screw rotates, but due to relative motion, the CAD script rotates the bottle around the cylinder,
and the bottles become the cutting object, as the bottles are booleen difference subtracted away from the cylinder, multiple times.

I think that the script needs to have added a rotation of the bottles about the cylinder, "centered" on the helix axis.

(I deleted my previous comments on 2d sweep, which was my faulty thinking.)

- Brian

Hi Brian, that sounds logical. Thanks for figuring it out!

Previously Barry wrote this:

"The bottle is always vertical to the horizontal
screws and only rotates in the plan view."

I was focused in on that "only rotates in the plan view" part and so only did one rotation.

So Barry, can you please clarify that so I can make sure - at each station you need the object rotated in 2 ways, once in the plan view which is rotating around the world z axis, correct? Then another rotation around the cylinder/helix axis direction which is the world x axis?

It might simplify things a little bit if the cylinder/helix axis was right on a world axis starting at the origin, will that restriction work for you?

- Michael

Here is an Initial model in Top View, for use with TOP frame.

Utilizing Michaels script BottleFeedArray (Top frame version), places the arrayed bottles along the helix where they need to be,
but the script needs to have added:
Each successive bottle needs to be rotated so that its center axis is perpendicular to the cylinders normal at that Pt.

I am pretty slow at getting anything done. :-)

Each angle could probably be calculated, or ...

(The initial bottle's center axis may not be tangent to the cylinder, but is perpendicular to the normal.)

- Brian

The angle to rotate a cutting bottle around a regular helix , for bottle at station n, is probably something like:

(#helix turns * 360) * n / (#stations-1)

assuming the initial bottle is at station index zero.

But since the helix may be of variable pitches, the angle would be some other unknown formula,
so perhaps a "normal to normal alignment" of the bottles vs the cylinder, would be better?

- Brian

The axis of the bottle, versus the surface of the cylinder is worrysome?

Burrman, thanks for link and info.

Hi michael,
So take a cutting object (a barrel) and do a circular array with vertical step.

Now each barrel needs to be rotated around "it's"original axis, 90 degrees from the first barrel at zero, to the last barrel at 90 (a rotation which spans the vertical distance. The barrel is essentially flopped over onto its side by the end of the array.

Now this needs to happen on a variable pitch, as opposed to a linear pitch of the circular array vertical step.

The "randomize" command allows for the "rotation of individual axis" but its a random application. I dont know if the "morph" rotation can be done with code though...