Common Origin for Large Assemblies

[lesmfunk]

We want to create common origins for first level assemblies in an existing model of a whole vehicle. We have inherited subassemblies with origins in random places. We prefer not to use a UCS, but rather move the actual origins to a common point such as center of front axle. Anyone know of a better idea than the method I have listed below?

1. Copy Design main assembly.

2. Insert new blank assembly into copied main assembly and constrain to origin.

3. Drag all children of first-level assemblies into blank assembly and ground them.

4. Rename "blank" assembly to same as original first-level assembly.

5. Delete original assembly.

6. Repeat for all first-level assemblies (and subassemblies within first-level assemblies if desired).

Can anyone think of problems that might arise with my method?

[swalton · Accepted solution]

Are your sub-assemblies used in more than one main assembly?  If not, I think your workflow will be fine.  If so, you might have issues. Try copy-paste, that will preserve the constraints (IV 2014 and later I think) between the components in the sub without removing them from the sub. 

Two alternate workflows for you to think about:

I might put a problem sub in a "holder" assembly.  Ground and Root (in the Productivity drop down) the "holder" assembly in the main assembly.  Adjust the constraints in the "holder" assembly to move the sub as required in the main assemlby. If you set the "holder" assembly to the Phantom BOM type, I don't think it will show on a Parts list.  You can have several holder assemblies to locate each sub in a new location in different main assemblies. (or in a single main assembly)

I have also derived purchased assemblies into parts, suppressed/broken the link and used the move body command to translate/rotate the with respect to the part origin.  This workflow choice will not give you the correct COG if the purchased assemblies have different materials in the various components.

[lesmfunk]

Update:

My proposed workflow produces errors in corresponding .ipn exploded view and .idw (No duh!). I guessed it might be an issue when I started but I thought I'd see what happened anyway.

I like your idea about using "holder" assemblies and might pitch that to my colleagues. However, we already don't like the multi-levels of assemblies in some of the Design tools and T&P environment since it doesn't truly reflect the MRP system.

I'd like to use a UCS, but it is too cumbersome to define in open space in an assembly.

[blair]

With the T & P system, you need to plan how you want your BOM to reflect the flexible T & P. We have two distinct work-flows depending on which flexible T & P we are using. If we are working with flexible nylon air control lines that incorporate push-to connect fittings. We place these fitting in our model prior to doing the T & P runs. This way our BOM reflects all the fittings and the nylon lines are just nylon air-lines.

If we are creating hydraulic lines with pressed on fittings, we then place the fittings in the T & P run as part of that specific hydraulic line. That way the specific hydraulic IAM file reflects the hose and the two pressed on fittings. Since the T & P allows for fittings to be placed in the IAM at the time of the run we can still use our stock crimp-on fittings without even dealing with Content Center.

I can't really comment on the Origin's as I really unsure of your need for this with Inventor. When we create a new IAM for a commecial trailer, we ground a specific item such as the primary vehicle coupling device at the Origin Point so all our CoG is relative to this point.

[lesmfunk]

Blair,

Thanks for sharing your T&P work-flows. It seems we are doing something very similar, if not identical, to what you are doing.

The common origin idea comes from previously working with an engineer who worked for VW and Audi and now we have an engineer on staff who worked for a large transit bus company. They are sold on the common origin system. In fact, the bus company removes all constraints for all components once the origin is defined. Problem is, now we have inherited a vehicle assembly with origins in random positions.

I think I will be using something similar to swalton's "holder" assembly idea except I will create a phantom "ORIGIN.ipt" defined in the master assembly. Then I will copy ORIGIN.ipt into each existing subassembly and ground. Parts will not share a common origin with the master assembly.