topic Re: Triggering a child attribute update without using "Edit Component" in AutoCAD Electrical Forum

Triggering a child attribute update without using "Edit Component"

stefan.stamate — Thu, 09 Nov 2017 17:25:49 GMT

Does anybody know if it's possible to trigger a child attribute update if the parent block is not changed using the "Edit Component" option?

I have a dynamic block for a fuse holder which can change all the manufacturer, catalog, assembly and rating values on the parent and I would like to force the new values into the child components (useful in a case a 3-pole fuse holder). It looks to me like this update is done behind the scenes in AutoLISP.

There is the option in the menu Components->Cross Reference->Child Location Description Updates but I can't get it to work...

Re: Triggering a child attribute update without using "Edit Component"

dougmcalexander — Thu, 09 Nov 2017 18:01:21 GMT

Dynamic blocks are something used with plain vanilla AutoCAD. They are not compatible with AutoCAD Electrical, because the block name can be changed to a value that isn’t compatible with AutoCAD Electrical. The block names used by AutoCAD Electrical adhere to a specific scheme, which must be followed. Also, edits made with plain vanilla AutoCAD commands do not trigger automation, so downstream updates, including updates to the project scratch database, do not happen.

Autodesk chose not to disable plain vanilla AutoCAD commands that aren’t compatible with Electrical, to avoid the misconception that customers switching over from AutoCAD would not be able to go backwards and edit legacy drawings. Of course you can just switch the workspace or the profile and you have only the plain vanilla AutoCAD commands, thus proving that you have full AutoCAD functionality. But within the Electrical workspace and profile the AutoCAD menus are not disabled. The bottom line is that we must exercise the discipline not to use commands from the AutoCAD drafting engine that aren’t compatible with Electrical. Some of the plain vanilla AutoCAD commands are useful for certain circumstances but training is necessary in order to know when and when not to use such commands while editing an Electrical drawing. In my training classes I cover the do’s and do not’s.

If you are new to AutoCAD Electrical I would suggest that you only use commands available from the Project, Schematic, Panel, and Reports menu tabs until you can get training - or at least go through the built-in tutorials. Training and/or mentoring can pay for itself by helping you avoid pitfalls, and by helping you become more proficient before you create so many projects that are crippled and thus unable to take maximum advantage of the software’s automation.

It helps to keep in mind that Electrical is a separate application that uses the AutoCAD DWG format to save files, but Electrical must be in control. Electrical includes a data manager that must maintain synchronization with multiple relational databases.

Re: Triggering a child attribute update without using "Edit Component"

stefan.stamate — Thu, 09 Nov 2017 18:41:48 GMT

The parent block name is following the AutoCAD Electrical structure (in this case is hfu1), the child block name the same (hfu2). I am not new to AutoCAD Electrical. I am using the dynamic features to push in a new values for the fuse/fuse holder/ratings. If I click on Lookup after the selection the correct part is selected in the database, therefore it is a valid selection.

I understand that using plain AutoCAD commands will not trigger any automation and that's exactly why my question was how can I trigger the child attributes update? Do you have any idea why the "Components->Cross Reference->Child Location Description Update" might not transfer the attributes from parent to child even after I rebuild the database?

Edit: I found out why the update was not working: I had to select the parent block as well, not just the child components. The update is working now using the "Components->Cross Reference->Child Location Description Update" option. I would still be interested if this update can be done project wide or triggered manually.

Thanks!

Re: Triggering a child attribute update without using "Edit Component"

dougmcalexander — Thu, 09 Nov 2017 19:14:56 GMT

Electrical will push values into symbol attributes during a Catalog Lookup, via the TEXTVALUE field in the catalog database. When you assign a part number via Lookup, the software checks to see if there are any entries in the TEXTVALUE field. If it sees RATING1=5A it will push the string value 5A into the RATING1 attribute. If it sees DESC1=DC;DESC2=POWER SUPPLY;RATNG1=24VDC;RATING2=10A, a power supply symbol block would have two description fields/attributes and two rating fields/attributes written to.

The fuse records that are included from Autodesk already contain a TEXTVALUE entry to fill in the RATING1 attribute with the ampere rating of the fuse part number.

If you need to change the child values after an update to a parent the Child Location/Description Update utility should suffice. There are options to update the rating and MFG/CAT values as well as Installation/Location and Description Text. I have a video that illustrates this utility at the link below.

https://www.screencast.com/t/slufVu3Y2O

This utility doesn't function project-wide. In a case where I have a large number of changes to be made, I would opt for Exporting the Project to a spreadsheet, make the changes in Excel, and Import the changes from the spreadsheet to update the attributes project-wide. Just keep in mind that the update from spreadsheet utility simply changes attribute values, so no downstream automation will be triggered. This could present a problem if the form factor changed as a result of the part number change, and thus the footprint block must be changed. In that case you would need to change the footprint block yourself.

Re: Triggering a child attribute update without using "Edit Component"

jseefdrumr — Thu, 09 Nov 2017 19:25:00 GMT

To clarify on a minor point: (and to take a short ride down a deep rabbit-hole)

It doesn't matter if you properly name your dynamic block. It's actually the handle that matters, but a lot of us use 'name' interchangeably with 'handle'.

Every drawing has its database, internal to ACAD's programming, which keeps track of all that you do. It's a hexadecimal system. Every object has a hexadecimal 'handle', and it is by these handles that ACAD manages things. The names we apply to them are inconsequential to this aspect of how ACAD (and hence, how ACADE) works.

Once, long long ago, it could be relied on that an object's handle (always unique per drawing) would exist unchanged for the lifetime of the object. Then came dynamic blocks. Remember, everything inside that block has its own handle. As soon as you change one of them, something has to happen to the handle of the block that it's in, because the block no longer has the same handles inside of itself.

And so, every time you use a dynamic feature of a dynamic block, its handle changes to a random value that the software self-generates. When Doug said that a block name can be changed to a value that Electrical couldn't use, this is what he meant.

For this reason, don't expect to always get dynamic blocks to work, and never expect them to *always* automatically update. As soon as you do something to change its handle, the dynamic block will be broken insofar as ACADE updating functions are concerned.

Jim

Re: Triggering a child attribute update without using "Edit Component"

stefan.stamate — Fri, 10 Nov 2017 12:27:45 GMT

Thanks for your explanation and suggestions Doug! The Child Location/Description Update utility does the trick for I what I wanted and I don't need to update the footprints as mostly I will be using this before I create the back-plate layout.

Re: Triggering a child attribute update without using "Edit Component"

stefan.stamate — Fri, 10 Nov 2017 12:30:47 GMT

Thanks for the clarifications regarding handles and names Jim!

I knew the limitations and I didn't expect that the updates will be automatically after changing the parent block. I was more interested in triggering that update after making changes to the parent block and the Child Location/Description Update utility does the trick in my case.