Hi OSTexo,

excellent tuto! Nothing to add above what was already said.

I noticed a couple of things you did and I wonder why those are necessary?

1- You rotated your base screw cylinder, I think you said something about the seam but I still wonder why this operation is necessary?
2- You shrink things a couple of time also, I'd also like to know why this is necessary or useful?

Thanks,
Felix

PS. If you think you're a newbie, I wonder where that puts me...

Perhabs we should make a group or a channel on vimeo, where we can put together all MOI videos on vimeo.

Rudl

Hello Burrman,

Thanks for the observation you hit the nail on the head. My intent was to be able to give even new users like myself the ability to accomplish the project without too much searching around for how to run shortcuts, tweaks, etc. Even using this long procedure it only takes about 15 minutes to recreate this bolt from scratch. The nice thing is you are able to quickly create templates for the cutting objects and caps of different pitches of screws, bolts, connectors and just copy and paste them into your working document. Once all that data is complete it's just a matter of determining diameter of the thread, creating the helix and cutting so you could really get down to a few minutes to make the custom thread for just about any application through asset reuse.

I realize that most designers do not use that level of detail for their drawings, but for renders and manuals it's a nice touch that adds to the realism and understanding of the project and since I use MoI for quick start guides as one application being able to show detail when zoomed in helps the presentation. Thanks.

Hello FelixPQ,

I'm not sure whether I messed up somewhere else in the procedure but when coming up with it I found if I rotated the cylinder to keep the cutting edge that is parallel to the seam of the cylinder a bit away from each other I could get the desired result consistently. I don't know if I'm just imagining things but it seemed I had more trouble when I had the cuts getting very close to seams in the objects to be cut.

The shrink trimmed surface command seemed to help in the Boolean operations as well, however it is more habit for me than anything else since when exporting AI it makes the intersecting lines of the drawing match up correctly.

I wouldn't depend on my explanation or validity of these explanations, since I have no basis to say whether the extra procedures have a bearing on the successful outcome of the project or not, they might work quite well without them, but it probably doesn't hurt the process.

Well Done!

As a long time comprehensive tutorial provider myself, I would like to say that your tutorial was spot-on as video tutorials go. Not rushed, a clear voice, no unnecessary chatter and not too much in the way of excessive mouse movement. I would say that you have a real knack for video tutorials. Experience will help iron out the process and you may even start to get a real good feel for how you can create breaks for yourself in the process and then assemble with a video editor. I saw that in one spot and thought that it was well done. I hope that you will make additional MoI video tutorials.

On a more personal note. I have shied away from video tutorial because I know the effort they take to make. My tutorials have always been in PDF format (200 - 300 pages on average), but I occasionally include a supplemental video on some of the more difficult concepts. I really would like to delve more into video and may do so at some point on shorter project concepts.

Best regard.

OSTexo,

thanks for your answers, they help me better understand why you're using them.

I would have like to know if there are technical reasons for doing this. As you say, it seems to work better but is really the case and if so, why this isn't part of the operation or function?

Thanks again,
Felix

Hello Don,

Thanks for the compliment. I was not fully aware of how much time it took to bring all of the pieces together for a video. I'll think more about pacing and break points in my next video as well as trying to up the polish. Only 300 pages? Ouch, I can't imagine that. I'm at the other end of the spectrum trying to condense as much relevant information as possible into guides for the non technical individual. I haven't found a better product for producing clean AI files for the graphics that go to print. I'm confident that hidden line removal will be here at some point, that will make my process as easy as export, drag and drop into the formatting.

Hello FelixPQ,

Those questions are probably best answered by Michael Gibson, I have no idea why or if I'm imagining things when it comes to why I've had more success keep with these procedures. Thanks.

OSTexo,

I also thought Michael would have pitch in but I guess he's buzy with the new beta release, it's perfectly fine with me.

I appreciate your tutorial and your answers, if it works fine for you why change anything. But it could be a bug also, I just find having to do this kind of extra step is not very "MOIish" to say the least.

By the way, I happen to have an old Machinery's Hand Book 23 revised edition page 1481 "screw design profile" that I could send you if still needed.

Thanks for your time,
Felix

Hi Felix, could you maybe give me a quick description on what the extra step was, it was ShrinkTrimmedSrf is that correct?

What was the command being used right after that, was it the new Flow command or something else?

In the first v3 beta Flow was sensitive to the size of the underlying surface so it could help to use ShrinkTrimmedSrf on it, but this is changed for the new v3 beta which only uses the visible portion of the surface for Flow so it's basically like having ShrinkTrimmedSrf built in to it automatically.

That's the only thing that I can think of other than control point manipulation where ShrinkTrimmedSrf would be particularly significant.

- Michael

The question was on the rotation of the cylinders seam edge before boolean difference, to move the seam edge out of the other seam edges to prevent (I'll coin my new phrase here) "SEAM SLITHER", where two seam edges that may skim in and out of each other can cause boolean issues, or create segmentation that can cause the filleter to fail...

Oh yeah, yeah that's kind of a good practice overall because the more things you have running into and overlapping each other tends to make things more difficult for surface/surface intersection calculations.

So anytime you have a chance to reduce the complexity of an intersection by possibly rotating some particular seam edge out away from where it makes things more complicated is a good idea.

It would certainly be nice if it wasn't necessary, but setting things up with less complexity usually makes for less chance for things to get confused about 2 barely skimming things that you are trying to intersect.

Also it's not great for the filleter to have a bunch of complex diced up edges rather than a more simple edge structure. Filleting is a pretty sensitive area so it's usually a good idea to try and give it a more simple edge structure to deal with if it is possible to do so.

- Michael

Hello FelixPQ,
Can you scan and send? I'm sure there are some neat tidbits of information in that guide.

Hello Michael,
Thanks for the explanation on the seams, I'm not completely nuts (yet).

Hello Burrman,
Copyright that quick.

Hi Michael,

yes, ShrinkTrimmedSrf was one of the 2 points I raised. I look at the video again and ounce he did all the boolean diff, he separated the resulting solid even if every thing looked fine, use shrink and rejoin everything back together into a solid. Since he activated show points, it was obvious the shrink command had an effect. If I remember correctly, this was threaded part of the screw and he did the same procedure on the head of the screw before using union on the 2 parts.

I just wonder if these additional steps where really needed and or useful in some way. Having the control points on make's it obvious that shrinking provides a nicer underlying structure limited to the natural or actual boundaries of the object and it may be a good enough reason to do it but does it help down the line with other operations?

As for the other point I raised about why he rotated the cylinder, this was answered and I understand better why now.

I have a bad memory so I wouldn't know if these kind of detail or things to whatch for are mentioned in the docs somewhere, if not then maybe it could be a good idea to group all those little whatch for thing and maybe have some suggestion on how to prevent problems down the road.

Thanks,
Felix

Hi Felix, re: shrink trimmed surface -

> but does it help down the line with other operations?

No, not typically - under normal circumstances it should not make any difference if you shrink surfaces or not.

It could occasionally happen that there would be some difference due to a bug or sometimes shrinking can actually kill off some badly formed area of a surface like some area where it's self intersecting or jumbled control points or something like that. If that happens, then it can make a bigger difference, like for example if you tried to do an offset and some not immediately visible area of jumbled control points will make the offset go crazy trying to track along a surface normal that is bouncing all over the place, but if that area happens to get removed by ShrinkTrimmedSrf, then doing an offset after that could produce a better result.

One side effect of shrinking is that it will reduce file size by some amount though, because it discards some extra areas of surfaces and that reduces data size by some amount.

Another side effect though is that you won't be able to do an "untrim" (delete trim boundaries) to recover the full original surface that was being cut up - sometimes being able to recover the original surface can help when trying to repair objects.


If you want the smallest possible file size, then I guess that's one reason to do it...


Normally I would not think that you would see any difference from doing it or not - the main exception is the Flow command from the first v3 beta which uses the full underlying surface. That's not the case with Flow in the latest v3 beta anymore though.


- Michael

Hi Felix, one other thing I should mention is that showing control points itself (not necessarily shrinking surfaces) can be useful as a sort of diagnostic function to try and get some more information about the structure of a surface.

For example if something is not behaving right one of the things I will usually do is to view the control points of the surfaces to see if I can find any warning flags like strange clusterings of points or stuff like that.

Don't know if that applies to what you are asking about...

- Michael

Sometimes it can also be used as a workaround - if some operation is having some difficulty handling a particular surface calculation shrinking it can sometimes change it enough to happen to avoid the particular problem.

That doesn't necessarily mean that it's always _better_ to do a shrink - it's just that it can possibly change things enough to make calculations behave slightly differently, sometimes maybe avoiding a problem sometimes maybe running into some other problem.

But if something is not behaving well, it can be worth a shot to try it to see if that particular thing then behaves better.

- Michael

Michael,

so basically, file size, could remove potential issues with some command and it can't be reversed. Hopefully, it can't cause problem of its own either.

Thanks,
Felix

A really good tutorial, especially for beginners. I had some spare time today and had a go. Here is a render from Modo (25secs):



It's a 10mm bolt. I guessed the head size as a I couldn't be bothered to look it up, so it looks a bit small.