Hi Barry,

> I think it would be good to have a check box the same as in the helix
> creation to save confusion as normally these screws are in pairs.

I know it sounds simple to add in a checkbox but unfortunately it can take a surprising amount of time to make it work correctly with testing it. So unless you're blocked from being able to finish that's not something that I'd do right now anyway since it will probably take me much more time to do it than it would save you. I kind of thought that it should work ok on a reversed one, is it that the reversed one isn't centered on the origin maybe?


> Regarding achieving a smooth scroll I have been lofting the facet edges.
> Is it better to rebuild the bottle profile so there is only one seam for the Boolean operation and
> to give a continuous facet edge to loft ?

I'd think so - it would likely be good to reduce the number of edges and segments involved.

- Michael

Seems BottleFeedScrew follows only Helix not tapered ?

Hi Pilou, yes that's correct it only supports a fixed radius helix.

- Michael

Hi all,
Thank you Michael for your reply.
With the oval bottle, the results seem good, but more difficult to rectangular bottle and round corners.
I think the possibility to to run the script with a reverse twist helix option will be really good.
Best regards.
Nicolas.

Hi Nicolas,

re:
> I think the possibility to to run the script with a reverse twist helix option will be really good.

It's not really feasible to make a reverse twist helix option for this particular script because the script does not generate any twist of its own, the twist comes from the helix you give it. The script just generates points along whatever helix you've supplied. So a reverse twist helix should work ok, as long as it is following the requirements of the script which is that the helix axis should be positioned at the origin.

Is it possible your reverse twist helix is off to the side and not positioned at the origin like the script is expecting? If that's not it please post an example file.

- Michael

Hi Michael,
See attached files.

The script will work fine on a left hand screw, if the initial setup is done in the proper way.
The key is to create the left hand helix (LH), just like the initial right hand helix (RH).
Then move the LH helix to the Left of the bottle, then FLIP the moved LH helix.
(It will be necessary to have a new blank screw/cylinder located to the left of the initial bottle.)
Then run Michaels script, with -90 rotation, because the array is done from left to right.
This preserves the Counterclockwise rotation of the bottle.
After the Boolean(s) have created the LH screw, in TOP view, rotate the entire LH screw clockwise about the center of the bottle, by -180 degrees.
This places the LH screw at "top of MoI screen."
The original RH screw is at "bottom of MoI screen."
(The above steps produce a LH screw which is equivalent to Barry's mirror method IHMO, (I think).)

Geometry remarks on LH, RH, CW and CCW, which may or may not depend upon the position of the person viewing:
A RH screw remains a RH screw, regardless of how it is rotated in MoI.
A LH screw remains a LH screw, regardless of how it is rotated in MoI.
The bottle needs to rotate Counterclockwise (CCW) from the TOP view, at all times.

If the bottleCutter and or either screw is rotated about the X-axis, from the TOP view, the bottleCutter will be rotating Clockwise (CW),
which is Opposite to what is desired.

But if the bottleCutter is rotated about the Z-axis, from the TOP view, the bottleCutter will still be rotating Counterclockwise (CCW),
which is what is desired.

- Brian

Additional remark:
The bottle needs to be pushed "gravity downwards" by each screw, or it could become airborne.
Looking from the Left side of the machine, the LH TopOfScreen screw should rotate CW.
Looking from the Left side of the machine, the RH BottoomOfScreen screw should rotate CCW.

(One UTube video has the bottle rotating CW from TOP view, which is opposite from our current models.)

Hi Nicolas,

> See attached files.

Yeah it's just the problem I mentioned above, your reverse helix does not have the helix/cylinder axis positioned at the 0,0,0 world origin.

In order to simplify the script it assumes that the helix axis is on the world x axis line. That doesn't mean just in the same direction as the x axis, it means directly on the world axis line.

I've attached an update of your file where I've moved the "Not working" one so its axis starts at the 0,0,0 world origin point, does it work ok for you now? I guess it may need a negative rotation angle as well (which I see Brian notes above too).

- Michael

Thank.
Script work fine in your 3dm file.
I must just think to launch the script with helix/cylinder axis positioned at the 0,0,0 world origin.
Very simply ;-)
Best regards.
Nicolas.

Hi,
Result
Barry

Hey Barry,
Here's my cheesy version. I wanted to setup a simulation, which should provide collision checking etc....But:



My opposing screw is still malformed for one. lol

But I also wanted to ask if you can share your process a bit deeper. Mostly with regard to the station count on your helical length, and also if you are using a slug "other" than the bottle (the one to be moved) to do the Booleans...

Your "bite curves" are beautiful and will help in the smooth surface creation. I HAVE gotten better results with higher counts, but still get SOME bad bites. Is there any magic you can share in this regard?

Thanks again. Fun project!

Hi Burr,
my shaft is 4 long x 1 diameter and the helix 4 coils. I used an ellipse 0.3 x 0.5 blank to produce the facets at 50 per coil.
The bottle rotation was 90 degrees over the length of the helix. In addition I added a run in and run out. This was done
by adding a single coil on each end with no rotation thus giving blanks to Boolean of one coil entry no rotation, four coils (Shaft)
90 degrees rotation, one coil exit no rotation.
For the opposite hand helix shaft I rotated the blank 180 degrees to move the seam thinking this will give a continuous facet
edge for lofting.
Hope this helps
Barry.
Ps how did you do your animation?

Hi BurrMan,
In your animation (Inventor?), your opposite screw seems one "mirror"?
My first tests with collision produce very surprising results. ("Flying bottle")
You need to pay a lot of attention when creating the screws and the intersect object.
My work does not leave me very little time to work on it "bottle feed screw" but really an interesting topic.
Thank all for that.

Hi Barry,
For provide one simulation with collision in real time, it's possible to use Simlab Mechanical (21day free trial).
The results are of good quality;
http://www.simlab-soft.com/3d-products/simlab-composer-mechanical.aspx
Best regards.
Nicolas.

Hi Barry,
Thanks for the breakdown. That will help me alot!
The animation is simlab. They have a simulation workbench, but i wont move there until i get the setup correct.

@nico

"My screw is malformed".... Yes!

Hey Nico,
""""My first test produces a flying bottle"""""

Have you made you plug a little bigger than your bottle?

I dont think 2 objects the same size would work in a proper sim environment...

Hi,
this is the result of lofting the facet edges to produce the scrolls.I reduced number of facets to 40 per coil
and made sure the seams of the bottle and the Can where not part of the subtraction as this ends up with
the facet edges in sections.
Thanks to Brian for the help with the node editor I've got it working with the quartz node so now I can run
the animation automatically without moving a slider.
Cheers
Barry