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J Tiers
06-25-2014, 07:59 PM
So I am now using solidworks. Thrown in the deep end, no book, only the help, nobody else at work knows how to use it. (I messed with it years ago)

Basically "here's the workstation, I need an animation of the new thing that isn't modeled yet by COB Wednesday" (it being Friday last week when I was told that.)

I DID get it done. Re-learned enough S-W to do the basic work in a half day and started in.

My problem is that of all the 20+ parts that had to be animated, I had two doors to animate that would not co-operate. The other parts all did. I could NOT get these two to swing around outside of the enclosure. The ones at the other end did fine. Yes, I can manually move them the right way

Picture long enclosure, with 4 doors, two on each side. They swing around to close on the long side, and open to lay against the short end when doors are "stored". I needed to animate them closing from the "stored" position, around to swing "shut". They wanted to go the "short way" through the model. ("Stuff" inside the enclosure was also animated, to happen before the doors closed, the doors are last)

I was animating with angle constraints and key times. Worked fine, especially when I cheated the angles 0.1 degree to "bias" them to go the correct way if they didn't seem to "want to" swing correctly.

All fine except the two. No amount of biasing and placing intermediate key times would help.... they would swing to my intermediate points, and then swing back around through the model.

I finally left them only partly closed, said "take it like this or do without", and got away with it. For now. probably a hack job, at least with the animation (model is done right)... I expected that, it was "anything to make it work" time this morning.

No reported bad constraints, so that's not an issue (I presume).

Is there another trick to the animation that I have not yet discovered?

Billy Hill
06-25-2014, 10:47 PM
Is switching to Blender an option? :)

Sorry, I don't use SW for much animation except exploded view animations, but it seems the Mates for a hinge would be fairly basic.

J Tiers
06-26-2014, 08:07 AM
Blender? I don't know... would any brand work as well, or does it have to be only "Oster"? :D

There is no issue with the angle mates, they always work OK.

The problem is in how the program interprets the path between them. As noted, for some reason it wants to go the wrong way , and there does not seem to be a direct fix. In Alibre, one might change the sign of the angle, making it negative might reverse it (I actually don't think I have ever tried that with angles, it works on distance dims).

I've asked about this on Solidworks forums, but no responses yet.

I would be a good software tester.... I find things that don't work as they seem to be intended. This ticks off folks who believe that the programmers are infallible, and that we should simply obediently conform to the program operation, making no suggestion or comment, even if it goes contrary to long-established standards.

There are a surprising number of such sheep.

Billy Hill
06-26-2014, 09:31 AM
I quit using the SW forum. Seems the "engineer" types over there are fixated with themselves and their narrow view of how the world works.

Programmers are another snooty type. They're wired differently and most of them think their **** don't stink and will find ANYTHING to convince you the problem isn't their software: "You just have to work around it by..." blah blah blah. LMFAO.

(And before any of you engineers and software guys get your panties in a bunch, I'm justified in saying that because in my decades-long machinist/programming career I've become both a competent mechanical engineer AND I do considerable software development and I work directly with experts in both fields.) :p

Anyway, I should have some coffee. Post back here if you find a solution, I'd be curious what it is and more importantly, how you arrived at the fix.

Tony
06-26-2014, 10:06 AM
It's been a bit since I've done animations but, from what I recall (and things may have changed), Solidworks will
interpolate between the two key frames you're trying to generate and will take the shortest path.

If you look in the help/tutorials there should be a tutorial on animating something that is spinning.

For example, if your door is opening 270*, you'll want to make your first keyframe at something less than 180, and
then your second keyframe at 270*. Make sure the time between keyframes is the same so that the opening happens
as one fluid motion (constant speed) during playback.

I think the other option is to add a motor (will only spin one direction) and turn the motor on and off at the right time.

Tony

Norman Bain
06-26-2014, 05:10 PM
So I am now using solidworks.

This one action may well reduce the blood pressure of more than one participant on the Alibre/Geomagic forum :p

Seriously though ... you do take the trouble to pen the words and get involved. It will be good to hear your comparison comments down the track some.

Cheers,
Norman

J Tiers
06-26-2014, 07:43 PM
Tony:

I did use intermediate keytimes, with partial (less than 90 deg) moves between them. Sometimes it would work up to the last one, but the last 30 deg (!) it would flip right back the long way. Other times it would revert earlier, and once even flipped back and forth before going the long way.

Oddly, it worked GREAT for two of the doors, going the "long way" with only the terminating keytimes defined. Not a problem in the world with those. I never had any issue getting them to work correctly the first time. Obviously the thing about trying to go the short way is not always true.

But it sure is true of the other pair of doors. They will go the short way even if it is longer!

I got what I had to do done. I was getting fairly fried by then, and was in no mood to fool around with the "motor" approach. Next time I think I will go there FIRST, and not try to fiddle with angles for that sort of animation.

The rest of the moving parts were mostly pushrods, arms, and misc parts, none of which had to turn more than 90 degrees during the animation. They responded to using the correct quadrants (angle-wise) of a 360 deg circle. I'd do that with angles again.

Norman:
Yep.... the only person with good sense over there seems to be Ralf.... he's sharp, and to the point.

And it isn't "Solidworks instead", it's "Solidworks also". I do not want to buy Solidworks, I just use it at work. If I wanted to spend that kind of money, I'd probably buy a CNC...

There is an inbred core group of folks who see nothing to improve in the program. If you DO think there is a need, you simply MUST be doing something wrong, the program is perfect.....

Some just believe that you should be grateful that the high and mighty take notice of you.... and accept their suggestions with a servile bow, even if they do not apply, and do not solve the problem.... Go away and be happy.... or perhaps "be ye then warmed and filled"..... even if the answers are "lacking the needful".

I notice that the newer folks are often not at all like that, many see the point immediately....