Learning Inventor's Implicit Behaviors

[MechMachineMan]

I was just wondering whether anyone has found out if there is any place to learn inventor's implicit behavior, or wheter we are just stuck in a path of self discovery.

For example; when loading an assembly, what actually happens? I'm assuming in the top level assembly, it first places the parts in their locations, and then checks the constraints against the part location and tweaks as needed. I'm guessing if any subassembly is made flexible it repeats this for that sub-assembly too. I'm also assuming sub assemblies are just located in sub assemblies as a "visual representation" of the sub-assemblies faces (unless made flexible).

Is there any more information on this kind of stuff out there? It would be useful for developing better techniques for our company as well as more efficient macros for working with models.

Thanks again!

[mcgyvr]

Never seen a company EVER give out that information as users don't need to know.

Your "tone" seems to suggest that should be common knowledge.. 

Been using Inventor since R8 and have NEVER needed to know whats "really happening" code line for line as far as what checks/functions the core code is actually doing..

I just know how the program works from a user standpoint. 

When a file is open and defer updates is not on it checks all constraints.. subassemblies included and gives you an error.. 

Not sure what else you really need to know..

What do you really need/expect to "develop better techniques" for your company?

Everything should be clear in how the program works.. 

Maybe you are asking about ilogic/vba training?

Maybe there is some more information for you in the customization forum.. 

[MechMachineMan]

As far as nailing down best practices for large assemblies with flexible
subassemblies and how to best use them so that it doesn't blow up, position
reps work properly in both assemblies and drawings, and contains don't blow
up only to fix themselves when updated.

[mcgyvr]

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@MechMachineMan wrote:
As far as nailing down best practices for large assemblies with flexible
subassemblies and how to best use them so that it doesn't blow up, position
reps work properly in both assemblies and drawings, and contains don't blow
up only to fix themselves when updated.

---

Best practice #1

In the event of unexpected constraint issues attempt a rebuild all/update before throwing your mouse at the screen. 🙂

These "blow up" issues.. Do you have a specific example that shows that behavior?

These kind of things have come up in the past and seem to be dataset specific issues and have never been 100% ironed out on Autodesks side... Probably because the users haven't shared the dataset with Autodesk to investigate or taken the time to "fully " report it.

I fall into that category too.. I've had "weird" issues in the past with certain assemblies/flexible subs,etc.. But I usually find its not a consistent issue and isn't worth my time to "investigate" deeper. It goes away and I move on. 

[johnsonshiue]

Hi! Justin,

Depends on how you load the assembly, by default, only the graphics is loaded. When you start editing or interacting with any of the component, the affected documents are loaded on-demand. There are things stored in the sub component documents (iam and ipt) and there are things stored at top level assembly. For example, the features or sketches are stored within the given documents where they are at. Flexibility, adaptivity, DV, PV, and LOD are stored in the assembly where these overrides exist.

Is there any particular reason or any particular workflow you are interested in?

Thanks!

[MechMachineMan]

The workflow for creation of large assemblies that have parts that need to be changed ~ 6 sub-assemblies down. Something Like an excavator with additional implements/attachments that all need to have some variation of changes shown for a top level assembly.

A workflow used before was to make everything flexible and leave it loose, but we constantly run into issues of broken constraints as soon as we change some part we have something constrained to.

The workflow I have been trying is to use Position Reps to have a more clear-cut idea of where the changes that messed up the top level are. The downside to these are that flexibility seems to break constraints a ton, so if we suppressed the flexibility for position reps, and leave it flexible for the master level, it still seems to compute for flexibility anyways, and won't change the flexible status in the sub-levels if a position rep calls for it (at least it doesn't show it from the top level tree_.

[johnsonshiue]

Hi! Justin,

I have seen cases like you alluded: constraints in flexible subassemblies tend to break more than flattened assembly. In theory, flexible subassembly is identical to flattened assembly with exception to the additional subassembly specific origin planes. Sometimes, it depends on how the flexible subassembly is constrained. If you can show me an example of fragile flexible subassembly, I am more than happy to take a look and see where the exact problem is.

Many thanks!

[blair]

A few things that help.

Don't constrain the pivot pin to a housing and then constrain the arm to the pin.  the Arm to the housing using the Pivot Hole, then constrain the pin to the housing hole.

Don't rely on the Min-Max of the travel of a ram. Set your Constraint Range Min-Max values to limit the movement range. Set your ram to Flexible just so it can stroke to match any movement.

Not sure it any of these will help you with your particular issues

[MechMachineMan]

By the Min-Max I'm assuming you mean a Contact Set?

[blair]

No, expand your Constraints Box and use the Limits. If you have an arm connected by a hydraulic cylinder that has a min retracted of 30" and a stroke of 24". Then set your Min to 30" and your Max of 54". You arm will only move within this range, no real need for the cylinder other than visual. Then set it to Flexible and constrain each end to the connection points.

The problem with Contact Sets, is if you move the item to fast, Inventor can't keep up with the solution set on larger models and you can get beyond the Contact Set limits.