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Joint tool - Applied limits disappear - rotational joint

16 REPLIES 16
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Message 1 of 17
JAudsley_SpectrumTechUK
1670 Views, 16 Replies

Joint tool - Applied limits disappear - rotational joint

Hi there,

I have been working on working 3D representation of an Igus cable chain, however when I place a joint with limits (to specify the range of movement, concurrent with the physical product) It will only work for a short period of time before the limits disappear. In the parts window to the left of the screen (default) I can view the applied joint on each part, where the limits are still in the text box, yet they aren't being applied to the model.

I then attempted to re-apply all the limits to the model, no change.

I restarted my software (Inventor Pro 2014) and tried again to no avail. 

Machine is a Dell Precision T3600, Intel Xeon CPU - E5-1620-0 @ 3.60GHz, 32gb RAM, running Windows 7 Professional 64-bit.

This appears to be a major flaw within the joint tool. I'd expect software bugs with new features but I'd say that this feature has not been thoroughly tested nor perfected. To have angular limits invisibly 'removed' with no prompt, error or conflict is something that needs to be addressed.

I don't have time to get screenshots together but the model is a direct download from Igus, of their E2 mini Chain, 10 series,

part number 10.050.028.           

If anyone can offer help or suggestions I would be very grateful.

Thank you.

16 REPLIES 16
Message 2 of 17

I have exactly the same problem. I set them up, drag the model around and they spontaneously disappear...
Message 3 of 17


@JAudsley_SpectrumTechUK wrote:

....   

If anyone can offer help or suggestions I would be very grateful.

....


I check them out each release, but then don't end up using them.  Seem to be geared more towards beginners and flashy VAR dog-and-pony shows.

 

I suggest using the standard assembly constraints (with limits) instead of Joints.


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Message 4 of 17
johnsonshiue
in reply to: andy

Hi! I have seen this behavior before. The limits are violated in order to have smoother solve result. Unfortunately, it is considered a limitation right now. We are aware of this request and we are actively seeking improvement here.

Many thanks for the feedback!

 

 



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 5 of 17
andy
in reply to: JDMather

Thanks for the suggestion about using conventional constraints with limits. This definitely has the advantage that the limits don't evaporate the moment the solution gets tricky but, unfortunately, the conventional constraint limits also don't seem always to be obeyed during a drag or while driving a constraint somewhere else on the assembly which causes the limited constraint to be exercised. So, slightly more robust but still not "limits" per se.

 

For what it's worth, I realise the kinematics and maths behind this are extremely tricky!

Message 6 of 17
JDMather
in reply to: andy


@Anonymous wrote:

.... or while driving a constraint ...

 

For what it's worth, I realise the kinematics and maths behind this are extremely tricky!


I have never had an error while using Drive Constraint where the computer could not keep up with the math, only when dragging with mouse.

 

You might look into Environments>Dynamic Simulation for a full set of motion Joints if you have Inventor Professional.


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Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional


The CADWhisperer YouTube Channel


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Message 7 of 17

Hi,

 

It seems I have the same problem stated here 1,5 years ago yet not solved by Autodesk. Applied slider limits randomly disappear (unchecked) if I insert the assemly that has the defined limits to another assembly and moving it. It is just a telescopic rail. I can't attach my whole assembly due to copyright. Making the joint protected won't help, it makes my assembly erroreous.

 

Any idea?

 

Thanks,

 

P.S.: and for god's sake, correct the error that prevents me adding an attachment! "The attachment's rail.rar content type (application/x-rar-compressed) does not match its file extension and has been removed." Same thing if I use ZIP.

Zoltan

Software: Product Design & Manufacturing Collection
OS: Windows 10 Professional x64
CPU: Core i5-8600K
RAM: 2*8Gb
VGA: GTX 3070
Message 8 of 17

Hi Johnson Shiue... I am hoping that you can define what constitutes a "smoother" result if the result is inaccurate and non-functional?  I am experiencing this phenomena in 2017.

 

With a large assembly, this type of limitation/bug is disastrous in it's scale if the user is not warned that "caution, system will randomly (if it's a limitation and not a bug, then I would expect the random part to be able to be clearly defined when it happens so I can try to design around it) delete limits applied in this dialog box".

 

Based on the 2014 response and my current encounter of it, I can only choose to abandon the joint functionality and return to constraints unless I am missing a checkbox in my setup or options somewhere.   

 

Can you guide me to some options that need to be checked in order to safeguard my application of joints?

 

Best Regards,

Message 9 of 17

Hi Larron,

 

The issue is that actually, there isn't a safeguard to prevent it from happening by default. You can right-click on a given Joint and check "Protected." It may reduce the chance that the angular limits are violated but I am not sure if it would obey it. Another possibility is to expand the angular limits.

I am replying based on my limited understanding of your issue. If you could share an example, I am more than happy to take a look.

Many thanks!



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 10 of 17

Hi, I have been using Fusion 360 for more than 3 years and never had an issue wit Joints limits resetting when i move the components, This year I decided to go for full product design suite only to get this behavior in Inventor, and even more surprising to me that this has been going since 2014 😞

In my case the slider joint limits gets changed when i lock the joint, my design has about 50 joints and i can't keep them all unlocked otherwise things become messy.

Can't inventor team get some guidance from Fusion 360 team!!

Message 11 of 17

I did more trials with my model, apparently the joint tool problems is related to nested assemblies.

When the joints is between two parts within the same assembly, the limits and lock works fine.

But if the joint is between two parts inside two different sub assemblies, this is when the problems with limits happen. 

Message 12 of 17

Hi! If possible, please share the files here. I would like to understand the behavior better.

Many thanks!

 



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 13 of 17

I cannot share my original file but i have recreated the issue in a simple file, here is a video of what is happening.

I also included the file.

So after some trial, i can clearly identify that the problem happens when there is a joint between two parts each one of them is inside an Adaptive Sub-Assembly.

Message 14 of 17

Please check my next comment.
Message 15 of 17

Hi! The file is incomplete. Please attach all files in zipped, including Sub-Assembly-01.iam and Sub-Assembly-02.iam.

Many thanks!



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer
Message 16 of 17

@johnsonshiue 

Sorry for that, i added the two missing files.

Regards,

Abdalla.

Message 17 of 17

Hi! Many thanks for sharing the files! I see the behavior now. It looks like a bug to me. I will work with the project team to see what we can do.

Thanks again!

 



Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer

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