I am trying to create an internal thread to boolean from the nut in todays movie tute but having this odd twist occuring.

V2--and I am sure I have done this before !

Brian

Hi Brian, well you certainly got an interesting result there! :)

The main thing is if you want to use the Twist:Flat option for sweep, you've got to get your path oriented along the world Z axis direction.

Then I'd also probably move your profile shape so that it is touching the rail as well.

I've attached a version with the curves set up like that - use the Twist:Flat option in Sweep on this one and I think you'll get the result you were looking for.

If you want the threads to be in a different orientation, you can then rotate the swept result. It is on the "todo" list to make it possible to define which direction is being fixed for the flat twist option but currently it is fixed to the z axis so you need to orient your sweep initially in that direction.

- Michael

I've found that the best way to control 'threads' like this is to do a 2 rail sweep, instead of 1 rail, with one of the rails being a line straight down the middle. the line down the middle keeps everything radial.

Thanks Michael----BUT!

I am staggered at that Z orientation necessity!
( I had also, in another earlier try, had the shape orientated on the helix line (as normal)--with the same results obviously)

And, two, did you follow through to get an actual thread into that file?

Still not really working for me with your file version for some reason?

Brian

Hi Brian,

> And, two, did you follow through to get an actual thread into that file?

Yup, I tested it over here before posting.

That's strange that you are not getting the same result - are you possibly missing setting the Twist:Flat option at the end?

Here is what it looks like over here:



Did I misunderstand the result that you are looking for?

- Michael

Also there is one other kind of odd bug with screw threads, which will happen if you use a helix path that has 6 turns in it.

That particular shape triggers a bug, there is a workaround described here:
http://moi3d.com/forum/messages.php?webtag=MOI&msg=1263.2

But you've got 8 turns in the one you've got there so you shouldn't be running into that particular problem here.

- Michael

Sorry Michael. I did not explain clearly enough.

Did you take you thread making through to the point to enable a boolean of the original nut?

I just can not get an end result showing the cut thread in the nut!

Brian

Hi Brian, no I only tested making the sweep part that you posted. I didn't notice that you had the other piece hidden in the same file.

To do the boolean I would recommend moving the sweep profile to the inside a little bit so that your thread is not skimming so barely along the inner surface of the nut.

It tends to be difficult for the boolean to calculate an intersection when a swept surface is just barely skimming along another part. The surfaces will not have a very well defined intersection there, there will be some portions that are barely sunk inside of the surface and some portions that are just barely barely protruding above the other surface, that causes problems.

So in this case that means moving the triangle slightly to the inside, like this:








I've attached a version created in this way and it is all set up to be booleaned.

- Michael

Ahhhh---Michael!

I had done those things---it appears that MY problem is visual perception!

It's just hard for programmes to show the result.

Sorry

Brian

Hi Brian, no problem! Yes, since that cut out piece is totally on the interior it is a bit hard to see.

- Michael

Michael/Petr

"The main thing is if you want to use the Twist:Flat option for sweep, you've got to get your path oriented along the world Z axis direction."(Michaels earlier post)

Is this documented anywhere?
Should it be in hidden secrets or something?

Brian

ps OK I found it on page 45 of the Help. However, for me, I think the help is a little ambiguous maybe and Michaels sentence above may be better.

But remembering is another matter.

Could the Flat (on the options list) have a little Z and up pointing arrow alongside it perhaps?

Brian

Hi Brian,

> Could the Flat (on the options list) have a little Z and up
> pointing arrow alongside it perhaps?

Rather than doing that, I think when I have a chance to work on it I will be switching things around so that you will have some different options for which direction is considered the "flat" direction instead of it being fixed to world Z.

Maybe I will also be able to have an "auto" direction mode that will align the direction automatically for helix curves.

- Michael