Multiple stable sketch positions

[viktor.deturck]

Hi, 

First of all, sorry if this topic has been discussed before, I couldn't immediately find related issues regarding this question.

Not really a huge problem but more to enhance my Inventor modelling skills, I sometimes come into situations with two (or more?) valid constrained positions in my sketch. Especially with parametric modelling, these sketches sometimes tend to switch to an other stable position further down the line, after which I have to manually modify the sketches/constraints again. 

1. Is this just 'bad' constraint practice, and should there always be ways to better define them? 

2. Is there a way to more easily switch back to the original position, instead of deleting constraints, moving the sketch and again constraining? 

Thanks in advance!

Picture below for reference:

[johnsonshiue]

Hi! I don't think you did anything wrong here. The issue is that Inventor 2D sketch dimension does not carry a sense. Though positive parameter values and negative parameter values are taken, the direction does not change. As a result, in some cases, the sketch can misbehave unexpectedly.

Please feel free to share the file here. I can work with the project team to see if there is a way to stabilize the particular 2D Sketch case.

Many thanks!

[viktor.deturck]

Hi John,

Thanks for your reply, as mentioned, it's more out of interest than finding a solution for this specific case (which by now is pretty much done). I came across it a couple times and was just wondering if there was a way of enhancing my way of building up my designs or if there was an easy workaround (like selecting between multiple stable states if things jumped around). 

Not a biggie, just always eager to learn!

Thanks again,

Viktor

[kacper.suchomski]

Hi

Such problems arise in situations of ambiguity. There are sets of dimensions (constraints) that can give many different logically consistent results.

In case of "misunderstanding" you can use the Relax mode (bottom bar or F11) and move the elements after constraint to improve their geometry.