topic Re: Frame Generator best workflow. in Inventor Forum

Frame Generator best workflow.

aurel_e — Tue, 26 May 2020 13:25:26 GMT

Hi all,

recently I am making more and more often simple steel platforms like that in the screenshots attached and sometimes more complex; with much more components. The problem is that I know my workflow is chaotic and the result is sometime unstable. I guess Inventor is not the best software for detailing the steel-work, but I hope someone in this forum can suggest some tips to improve. My workflow:

1. I create the frame using as skeleton an ipt made of sketches and surfaces.

2. Use of frame generator tools like miter, trim-extend, notch.

3. Place various sheetmetal plates (end plates, base plates. etc.) constraining them to the FG members.

4. Use bolted connection to place fasteners and drill holes (using the sheetmetal plate holes)

5. Use Demote FG components to create sub-assemblies for detailing purposes.

Here I start to have the first problems:

a)Constraints that are loosing the references.

b)Often I realize that I have in different positions the same subassy i.e. the same leg in 3 positions. For many reasons (like having only 1 PN), I would like to delete the other 2, copy or pattern the subassy. But if I try it, many times I will have problems with Trim-extend or notch references.

And if you consider the design changes (in 90% of the cases the customer changes the plans many times) the result is a big mess. I still manage to finish the job but in a way I would not be proud: the model is not anymore parametric, grounding the components, changing the PN manually, using sometime the direct edit.

Re: Frame Generator best workflow.

3D4Play — Tue, 26 May 2020 19:18:33 GMT

Your issues are common, and you are not alone in feeling frustrated. The thing you said that meant the most to me is that the customer makes changes, and those changes cause problems when you want to make those changes as quickly and efficiently as possible. FG is a powerful tool, but the more you use it, the more you appreciate its limitations, and its need for an exacting workflow.

I have this short list of reminders for FG:

Read the help files, in context with your workflows. Set aside some time to go through them with a practice assembly, so you can see first-hand what is supposed to happen.
Demoting FG components does not behave consistently with regard to constraints - sometimes the constraints persist, other times they are lost, sometimes they will throw an error, and other times they will just behave erratically. This same thing applies to bolted connections. This is why the help files suggest grounding the demoted or promoted assemblies.
Patterning FG components: see above
When you reuse FG members, the reuse must be EXACTLY like the base component. You cannot make a reused FG component "independent " like you can with patterned components. All of the end treatments, and all of the base orientations must be exactly like the base member's. Otherwise, if anything needs to be different, then you have to place new members with their own end treatments.
Take note of the preview orientation during member placement. Clicking at different ends of a sketch line will flip the orientation, and this single trick has been most valuable to me. However, to make things ever so much more complicated, the FG tool has both a "flip" and an "align" feature, which will confuse you again once you click the other end of a sketch line. I used to have a tendency to simply "click first, curse later". Now it is more like "preview first, laugh a lot, smack forehead once or twice, then click."
Keep your sense of humor.
You can also "align" to faces or edges. This feature works erratically, so it's best to play with it first, to get a better sense of "what" aligns with "what" when you use this tool. I think it is intended to work like "something will align with something". It works well when the frame member sketch elements are all pointing in the same direction on the same plane, but when you select multiple sketch elements that point in different directions (two lines at right angles to each other, for example), the "alignment" will get confused.
Keep your sense of humor, and use preview profusely. Let go of the "click faster means work faster" mentality, because you will only be clicking undo faster and more frequently.

Re: Frame Generator best workflow.

jtylerbc — Tue, 26 May 2020 21:37:06 GMT

@aurel_e wrote:

5. Use Demote FG components to create sub-assemblies for detailing purposes.

As an alternative workflow for dealing with the odd behaviors of Demoting frame members, consider creating these subassemblies as a separate frame in the first place, using the same layout part. That way you can control the main and sub-frames together, keep them fully parametric, and still have the desired BOM structure.

In this method you can't have frame members in the subassembly trimmed to the members of the main frame. But if they need to be, I'm not sure I would consider them a viable sub-frame in the first place. However, you can tie them together in various ways by trimming to common work planes in the layout part, so it is possible to associate them indirectly.

Re: Frame Generator best workflow.

3D4Play — Tue, 26 May 2020 23:19:05 GMT

+1 that tip. I use it all of the time for visibility purposes in drawings, too - select and change visibility by single assembly rather than individual frame members.

Re: Frame Generator best workflow.

aurel_e — Wed, 27 May 2020 07:23:24 GMT

@3D4Play

Thank you for your tips. I knew some of the problems you have described. I have abandoned the reuse tool after discovering it was not reliable in some cases. The fact that you still use it means that i have to investigate its behavior and understand when it might be beneficial.

Yes, Inventor is a powerful software but... too many: "but"s, "...be careful..." "... not always...". Sometimes it's inconsistent or unpredictable.

Some time ago I bumped in this other post where another frustrated user has described Inventor as

"... possessed by a demon imp whose job it is to figure out what
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..."

I liked it and printed it to remind me I'm not the only one to be frustrated and yes to "keep the sense of humor"

Re: Frame Generator best workflow.

aurel_e — Wed, 27 May 2020 07:29:00 GMT

Thank you @jtylerbc

I suppose you create in place the subassy and insert in it the same Ipt skeleton

Re: Frame Generator best workflow.

jtylerbc — Wed, 27 May 2020 13:21:51 GMT

That would probably work fine, but it's not typically how I do it. I tend to be pretty picky about origin locations, so I would tend to do it a little differently just to make sure the origins are set up exactly the way I want them.

I would usually create the subassembly separately, and drop in the layout part (grounded at the origin or constrained to it). Then I would drop the subassembly into the main assembly, and either ground it at the origin or constrain it to the origin. Now everything has common, matching origin locations, and I would be ready to start building up the frames.