Parameter variable error - Unable to use variable as parameter

[matt.soule]

Had a strange thing happen on a assembly model I have been working with on and off for quite a while.  Took me a while to figure out how to fix it so I thought I would share what I found and maybe help someone else save a little time.   I could not find any reference to the issue on the forums.

I went to use a variable from early in the model (d39 to be exact - I am up to 720 or so) and the parameter would not be taken as an offset in a joint I was trying to make.  It would just stay red in the input box like it does when the units don't match or the variable or user parameter is not recognized.  It would not be taken for anything else either like a dimension in a sketch.  I knew it was there I could see it in the parameter list.

Here is what I found:

This is what parameter d39 looked like in the parameter listing.  (I am working in fractions.)

Linerar Dimension-2        d39       in       5/16"       0.3125

So I clicked on the expression [5/16"] and changed it to 3/16.  By the way when I selected it, it turned red like it did not understand it.  I typed in 3/16 hit enter and lo and behold it updated the model and the expression entry changed to (3 / 16) * 1 in.  I changed it back to 5/16 and the model updated and it reads as you might have guessed (5 / 16) * 1 in and all is now right with the world.  I can use as a parameter. 

I also note that the more recent linear variables I have made are already in the updated (?) format.

I suspect maybe that the way 360 handles units was updated at some point in time to a new method and old variables are getting stuck but who knows.  At least I (we) know haw to fix it now.

[jeff_strater · Accepted solution]

Hi @matt.soule, thanks for the post.  Interesting symptom.  I don't remember a recent change, but if you've been using this assembly for a while, the Fusion change could have happened a while ago.  Thanks for your diligence in digging in and finding a workaround and posting it.

If this is a model you can share, can you send me a link to the older version that showed the problem?  I'd like to take a look at it to see if we can pinpoint when this happened and whether we should take any action to try to auto-correct expressions like these if we run into them in the future.

Jeff

[matt.soule]

Hi Jeff
Thank you for your prompt attention.  Here is the link, I hope.
https://a360.co/2qd9trK

Once again, the variable in question id d39 but many others exhibit the same issue.
BTW I am I guess what you would call a hobbyist but I have had years of experience with Ubigraphics NX.  The partially developed model is of a mechanism to help dock a sailboat if you are single handing it or old like me.  Kudos to Autodesk for making advanced software like this available to people like me at such a reasonable price (free!).  I wouldn't be doing this otherwise.  After I make my first 100K on this invention I will be purchasing my license - but don't hold your breath.
Matt