Multiple parts becoming identical after revising the assembly

[Denimoth]

I have the following question about Inventor. Say I have an assembly file that has 7 different lengths of tubing. I then need to modify this assembly (for whatever reason) and the changes results in 3 lengths of tubing to become identical in size and length.

 

Does inventor automatically figure out that instead of having 7 different parts, there are really only 5 (the 5th having 3 instances of the same part) and therefor treats it accordingly in the BOM, parts and drawings files?

 

What about the reverse? If I have 5 different lengths of tubing with the 5th having 3 instances of the same part, and then I change the assembly file and now all 7 tubes are of different size or shape, does inventor automatically create the part files for the new parts?

 

I'm not sure if I'm explaining this right or not, but if it isn't clear, please let me know and I'll see if I can clarify it some more.

 

Any help in answering this question would be greatly appreciated.

[Pablo Ferral]

Yes and no... Imagine that an Inventor assembly is a database and that each part file is an entry in that database. Inventor will count the number of each part file in the database to include in your BOM. If you need to have differnt attributes, you need to have different parts - Of course there are ways of having one part with many attributes (iParts) or having many parts with the same attributes, if that's what you need.

 

In this case 7 different parts with 7 different lengths would be picked up as 7 different items in your BOM. 7 Parts with three parts being equal would be picked up as 5 items (But why wouldn't you use the same part 3 times, rather than 3 equal parts?!)

 

in answer to your second question - Inventor won't automatically create new parts in this way, You would need to create the new parts and insert them into your assembly (unless your using the frame generator).

 

All of this relies on you having your BOM configured to pick up 'Length' as an attribute.

 

Here's some good tutorials:

http://www.sdotson.com/tutorials.asp

[Denimoth]

Thanks for your reply Pablo.

 

The reason I'm asking the question is that I want to use Inventor to draw up some ornamental railings for stairs. Someone might say that's real easy to do, but in the real world, we do the initial drawings first to get the design intent approved by the architect. Then the drawings sit in a corner gathering dust until we can get someone to go to the construction site and measure the steel stairs that we are installing the railings on (I've had projects sitting away for almost a year like this). What the site has and what is shown on the architectural drawings are often times two very different things (frustrating, but it's how it is). So imagine railings on the left stair stringer should be identical to the right side, but after measuring the steel stringers on site, the right side might be 1/2" (13mm) longer than the left, and the top of the stringer is higher than the left by 5/8" (16mm). We have to modify our railings to match these new dimensions, which results in many items that are identical (such as the vertical posts of the railings) now becoming different (right stringer vs left stringer). Do this for a stair that spans a few stories and we're talking many changes.

 

It'd be nice to use the same part many times over in the initial drawing, but then I'd have to redo them all after revising the drawings for the site condition because they all be the same anymore.

[Mike_Taylor]

Which version of inventor are you using?

 

If you are using Inventor 2011, there is a new feature that allows for rule based design.

Inventor Features and Demos

 

Click on the Rules Based Design video. I have not used it yet, as i have yet to get a hold of Inventor 2011, but from the issues you are having this may be the solution.

[Denimoth]

Thanks Mike, I'll take a look at that link. I'm currently using Inventor 2010, but updating the software could be a solution.

[Pablo Ferral]

Yep, Inventor is for you. Look into skeletal modelling and the frame generator. This will save you hours of draughting. If you can wrap your head around iCopy and iLogic you could be on to a real winner.