topic Re: Constraints behaving oddly in Inventor Forum

Constraints behaving oddly

office6PUWT — Wed, 09 Mar 2022 09:49:44 GMT

I've been having an ongoing issue when applying constraints in that whilst I am hearing the familiar clicking sound that usually accompanies the part being placed nothing is happening. When the problem started I was having to reselect the contraint dialogue box for the previous part to appear in place according to it's constraints it's now stopped working altogther. This would perhaps suggest a software issue but I'm wondering also if I have inadvertantly adjusted the document settings in a way so as to cause this issue. I'd be grateful though to anyone who could shed further light on the issue. I'm afraid I don't how to attached .iam files whilst including all the relevent .ipt files as a single attachment so have not attached the file in question but am finding this problem to be an issue across all my assembly files.

cheers

Luke

Re: Constraints behaving oddly

kristin.jakuszanek — Wed, 09 Mar 2022 13:27:56 GMT

When you have the constraints box open is your 'show preview' button checked? (glasses symbol).
I have found I will occasionally tick this off and it will still make the noises like a constraint is happening, but it won't immediately show you the constraint happening until you actually hit the ok to apply it.

Re: Constraints behaving oddly

office6PUWT — Wed, 09 Mar 2022 16:36:29 GMT

I noticed that the preview option was in fact turned off and after a quick google learned that it won't be available whilst Tools/Options/Assembly/Defer Update box is checked which it was. I remember checking this box at around the time the problem started as a fix to another problem so hopefully I should be ok from now. Thanks again.

Re: Constraints behaving oddly

johnsonshiue — Wed, 09 Mar 2022 22:00:30 GMT

Hi! When the assembly Defer Update is on, the constraint solve will not happen immediately. The solve happens when you click Update, or drag a component, or do Rebuild All.

If you can show a workflow exhibits an unreasonable behavior, please share the steps or record a video. I would like to understand it better.

Many thanks!

Re: Constraints behaving oddly

office6PUWT — Thu, 10 Mar 2022 07:07:17 GMT

Thankyou, I'm trying to remember why I had turned on the Defer Update beforehand as I had previously solved another issue I was having by doing so but it is working now as expected, next stop iMates! I would be grateful if you could suggest a good online tutorial on best practice with regard to constraineing sketches as I am really struggling to find ways to adhere to convention when creating more complex sketches and end up either autoconstraining or just leaving them unconstrained. I don't reall understand which constraints to use, where or why.
all best
Luke

Re: Constraints behaving oddly

johnsonshiue — Thu, 10 Mar 2022 19:06:11 GMT

Hi! There are plenty of good learning materials on parametric sketching by various CAD vendors. They are generally similar.

Besides testing, I rarely use Auto-Dimension command. It is because the command does not have sense of design intent and engineering principle. Arbitrarily adding constraints and dimension will lead to unnecessary complexity.

The rule of thumb is to keep each sketch as simple as possible. You never want to overload a sketch. Likely some of the detail could be done in other sketches or features.

Another commonly overlook workflow is using Sketch Blocks. In many cases, a shape can be repeated in a sketch. You may define it as a sketch block. The sketch geometry within a sketch block has zero degree of freedom. It helps reduce the amount of dimensions and constraints needed to fully constrain the sketch.

Please feel free to share an example. Forum experts can help take a look and provide further guidance.

Many thanks!