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Ok, I've got to agree with my Engineer here....

Patriot_1776
22-Sapphire I

Ok, I've got to agree with my Engineer here....

....who came from Solidworks. I'm doing some assemblies with motion and the "mechanism" constraints totally, utterly, absolutely s#ck. Totally a pain to use. Non-intuitive. Things that should take me a few minutes are a huge struggle.

Needs fixed.


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14 REPLIES 14

Progressively getting more p!ssed off..........

This is one of the worst things on parametric modeling. Everything needs all those stupid constraints.

Only sketches constraint themself automatically, but atm it's just like all the other stuff couldn't. ^.^

On every hole even the one i don't really mean to place precisely i have to drag the stupid handles, zoom in and zoom out numerous times........

At least for assembling components there is this thing called docked assembly window. Not sure if its also in releases before Creo 1.0

Hi Jakub...

Yes, the docked window existed prior to Creo. There's an option in the config.pro to turn it on.

I've been struggling all afternoon to try and get some mechanism constraints that SHOULD work, to work. Pretty f^(*%$% simple mechanism, but pretty impossible to get to work. This is stupid. It'd been 5 years since I did any, and now I remember how much of a total PITA is was......

A simple "pin" constraint takes a PhD to get to work. SRSLY??

Like I said, on this, I TOALLY agree with my x-S/W Engineer that the mechanism constraints are pathetic....

dont know how complex motion you need to do, but in my view, it's not very hard to use mechanism. i have finished some motion animations like transmition mechanism.

i think your problem is dont familiar with it. it's different with solidworks.

maybe i can help u if u want , send me a email.

wish u fix it quickly.

Let's see if I can't waste more time today on something that should have teken 10min yesterday that took hours....

Hi Frank...

My experience with Mechanisms is that you do sometimes have to play with it a little. I don't have much trouble though. Sometimes I loosen the tolerance on the mechanism connections until I dial everything in.

What are you trying to do... a motion envelope, an animation, or just modeling a mechanism?

As with everything else... once you work with it for a bit, it all makes sense. Is this a really ugly mechanism or is it relatviely simple? I've done some fairly complex motions before using the mechanism functions.

The revolutionary Ion Thrusters on NASA's Dawn Spacecraft were modeled and manipulated using Pro/ENGINEER's mechanism functions way back in Pro/E v. 2001 (I know because I did it). There were multiple servo motors and linkages used to reposition those thrusters and Pro/E handled it without a problem. Here's a link that discusses the ion engines if anyone's interested.

http://www.space.com/8579-nasa-spacecraft-breaks-speed-boost-record.html

Anyway... ahem... pardon the name dropping. If there's anything I can do to help you through your Mechanism issues, let me know (or write to me offline).

Hope you have a great weekend!

-Brian

It SHOULD be a snap, a pretty simple linkage that's activated via 2 cam slots. Not even a single servo motor. But, it's been nothing but trouble and wasted time.

I went to the link, cool stuff! I'd love to see the models just for fun. NASA certainly does some cool stuff. I enjoyed my time there. I'll get a hold of you, thanks!

Still struggling with a connection that should be a no-brainer. My S/W guys assure me this would have taken them 15min. The Mechanism constraints NEED, repeat NEED to be more user-friendly, and CERTAINLY far more robust. Still can't get the stupid thing to work. Wasted 2 days on it now........

Unless Brian has some tricks up his sleeve, I'm going to count this as a FAIL. That Mechanism is just not capable of the motion I need. I need to quit wasting time on it and work on the actual design instead.

Is there an add-on package for mechanisms from another company I could purchase and use instead?

Can you post the Pro/Fanity components so we can take a look?

Patriot_1776
22-Sapphire I
(To:KrisR)

Hah! I'd list them, but my post would be deleted!

Hi Frank...

I am working on this. It took awhile to fully understand the way the skeleton was working.

I'm playing with some curves to help drive the motion. This is more robust than relying on the surface of the slots to control the motion. Mechanisms can stick to curves like a train on a rail... but they can get a little sloppy when they're not well constrained.

I'll have something for you today before I leave.

Thanks!

-B

Buried in the parts are the curves I was trying to use to drive the mechanism, because I was afraid of that. But, even constraining the point feature to the curve didn't work. I purposely made the curve not exactly in the center of the slot to simulate the bearing surface under loading.

Thanks, you RAWK!

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