Will Inventor Ever Fix the Angle Constraint ?

[Anonymous]

Maybe I've just been doing it wrong for the last 5 years, but the Angle constraint is obnoxiously unpredictable. When I constrain a part in an assembly with an angle constraint from the assembly origin plane (or anything else), Inventor always has two solutions; a positive and negative.

Is there something I'm missing here, or is just a design flaw we have to live with?

[Anonymous]

wrote in message news:6352462@discussion.autodesk.com...
Maybe I've just been doing it wrong for the last 5 years, but the Angle
constraint is obnoxiously unpredictable. When I constrain a part in an
assembly with an angle constraint from the assembly origin plane (or
anything else), Inventor always has two solutions; a positive and negative.

Is there something I'm missing here, or is just a design flaw we have to
live with?

_________________________

Inventor is possessed by a demon imp whose job it is to figure out which
angle you are trying to achieve, and doing exactly the opposite 78% of the
time. The 22% that he does it right is just to keep you confused. A few
versions ago Autodesk added a button to the dialog box which (I guess) was
supposed to fix the problem. My theory is that selecting that button
activates a sharp stick that repeatedly pokes the demon imp in the rear,
causing him to hate you personally.

And you're correct; if the last five years is any indication, there is no
possible remedy to this problem.

Cheers,
Walt

[Anonymous]

This software has been a wonderful tool, but this "design flaw" needs to be fixed once and for all.

[JDMather]

One thing I do that seems to help is turn on Predict Offset (and Orientation) when placing angle constraints. Just be sure not to forget to enter your distance to replace the prediction. Also don't forget to turn off Predict Offset when done as this can cause major problems when you don't realize it is active.

[Anonymous]

Well, I'm attempting to make an iAssembly when I get this model completed. The angle values will need to vary from +3deg to -3deg. I've tried the predictive method, but that only assists with the initial value I give it. In fact, I can toggle between +3,-3,0 several times, and Inventor changes it's mind randomly as to which direction is positive and negative.

[Anonymous]

would it cause problems for you if you use 3 to 357 and skip using the
negative 3?

[Anonymous]

I have best results with the Explicit Reference Vector method and using edges rather than faces.
Have you tried Explicit Reference Vector?


from help:
Explicit Reference Vector Explicitly defines direction of Z axis vector (Cross Product) by adding a third pick to the selection process. Reduces tendency of angle constraint to switch to an alternate solution during a constraint drive or drag. Edited by: Bmiller63 on Mar 10, 2010 9:47 PM

[Anonymous]

I combined both of your suggestions, and I'm having much better luck. I've used the explicit vector refence, and abandoned the negative values. It's reacting much better now. Thanks so much.

[Anonymous]

you're very welcome.
I understand where you're coming from, I fought that for years until they added the explicit vector option in INV2009. I forget where I learned to use edges rather than faces, but I'm guessing it was from this forum.

[robmatthews]

Going past Zero bites. If there are two angles, or you need to drive the angle, i like to use positive angles from a different reference plane or edge.

[Anonymous]

Exactly what I was going to suggest.

Whenever I've got a dim that's likely to swing through 0 (whether an angle
or linear dim) I find it best to use, or even create, a reference plane
offset enough of a distance so it's always a positive distance/angle from
it.

e.g. for an angle going -3 to +3 - try a face (or plane) 90degrees to this
so the play is 87 to 93 degrees.
For a linear dim moving -15 to +15 create a plane, or perpendicular surface,
100 away so the movement is 85 to 115.

Hope that helps, Sam

wrote in message news:6352594@discussion.autodesk.com...
Going past Zero bites. If there are two angles, or you need to drive the
angle, i like to use positive angles from a different reference plane or
edge.

[SMPConsulting]

I am bumping this thread to see if progress has been made on the angle constraint issue.

This problem has been around for a long time and I'm wondering if there are any additional tips or video tutorials that could shed some light on the matter.

I've been using IV since around 2002 and every now and then I do design where angle constraints just drive me crazy, like now.

I've tried the tip suggested by Bmiller63 but the results are unpredictable, i.e.. works sometimes and not others. Strange.

[blair]

You should see some improvement in 2014 in this area.

[SMPConsulting]

Thanks for the response Blair. What do you know, is Autodesk aware of the issues and working on something?

[autocad1RY3QB]

Hi folks, the jumping like a loop angle in animation is still here, even if u use only positive values 🙂 8 years is not enough for Inventor to solve such a trivial problem. I'm using Inventor 2018 and directed angle still doing random.

Any idea how to make them (inventor programmers) work for our licence money?

[mcgyvr]

---

@autocad1RY3QB wrote:

Hi folks, the jumping like a loop angle in animation is still here, even if u use only positive values 🙂 8 years is not enough for Inventor to solve such a trivial problem. I'm using Inventor 2018 and directed angle still doing random.

Any idea how to make them (inventor programmers) work for our licence money?

---

@autocad1RY3QB Can you post files that show the problem you are having? Have you tried to use the explicit vector option that was put in place to address issues with the angle constraint..

There is no "bang for the buck" in fixing old issues for Autodesk.. But we as users might be able to help you find a workaround to your issue or show you how the problem should be solved.. or at the very least express our condolences and poke at Autodesk with you....

Having a real model that clearly shows the issue is the best way to communicate these issues and make forward progress...  

[johnsonshiue]

@autocad1RY3QB,

Hi! Please share an example exhibiting the behavior. I suspect it would work better if the explicit vector angular constraint was used.

Just to clarify what Brian said, it is not true that Inventor team ignores old defects. We do try fixing defects regardless of their ages. When it comes to fixing, every defect has gone through thorough review process for its risk and feasibility. Most of the time, the unfixed defects are due to significant technical risk involved. Fixing it could make the matter worse. It sounds counter-intuitive but it is true.

Many thanks!