Content Center Calculation Error

[b.mccarthy]

Hello.

I am creating content for aircraft fasteners, AN grade. The fastener lengths are given in fractional lengths of 1/32" increments. For many numerical values (depending upon how the column is set up), the decimal calculation can be performed in the cell, i.e.: Enter 1/2 and you get 0.5, 3/16 becomes 0.1875. Where this breaks down is on the smaller fractional values: 17/32 gives me this:

Does anyone else see this happening?

[gregory_nickol]

Just opened up my CC editor and tested on my system real quick and got the exact same number. So it looks like it's an Inventor issue, not something unique to your system. My guess is it's some sort of glitch with inventor converting it to an internal metric unit system for storing the value and truncating somewhere along the line, then converting back for the displayed value. The values are off by a consistent amount for me.

Interesting thing to note, it seems to be fine up through 11/32", then gives +/-0 0.00000197", which is very close to 5*10^-5 mm:

11/32"(0.34375) gives 0.34375

13/32"(0.40625) gives 0.40625197

15/32"(0.46875) gives 0.46875197

17/32" (0.53125) gives 0.53124803

19/32" (0.59375) gives 0.59374803

the next 3 are +0.00000197, then the last 3 are  -0.00000197

I'm running Inventor Pro. 2020.4.3 on Windows 10 for reference.

[b.mccarthy]

Thank you for verifying this...

My sanity remains intact... (...mostly...)

[gregory_nickol]

The weirdest part for me is the inconsistency. The AMOUNT that the numbers are off is indicative of converting to meters, rounding to 7 decimal places, then converting back. However If it was just a straight rounding or truncation I would expect it for all the X/32" values, and I would expect it to be always +0.00000197 or always -0.00000197, but for some reason it's not treating all the numbers the same. They all end in 5 and should be rounded the same.  Considering that you can manually type the intended decimal inch values in with no issue, it seems to me like a problem with the code that actually calculates from a fractional inch value.

[jan_priban]

Hello guys,

it is interesting that I see correct behavior in Content Center family dialog and my colleague sees correct behavior in parameters table. I revalidated fractional in R 2022.2 for all 12/32, 11/32 10/32 ... and all such fractional values are converted to decimal number correctly. Example / image bellow is for 5/32. Do you use "dot" or "comma" as symbol / separator on your PC?  I am using "dot"

Regards

Jan Priban

[gregory_nickol]

@jan_priban 

I use the "dot" separator, but in this workflow we're not typing that in. Typing the exact decimal values in works fine, it's just a lot more work. (Typing 17/32 is much faster than typing 0.53125, especially if you don't know the conversion already and have to calculate it). If you look at this first sample image below, you'll see that the value being typed in is"13/32", then on the second image below, after leaving the cell, it converts "13/32" to "0.40625197". 

On the screenshot you included I see the units are set to mm for the column you tested. Did you try it with a column set to inches? I just tested on a column with units set to mm, and the error does not appear to exist in this case after typing fractions into there (image 3 below).

@b.mccarthy For a workaround if you have to do this a lot I would suggest editing using excel so you can format cells as fractions, then type the values in, then when excel sends the values BACK to inventor, it sends them as the decimal equivalent instead of as the fractions.

[b.mccarthy]

@gregory_nickol 

Thank you for the input. Yes, the Excel option is one of the workarounds, but involves extra steps and time. I feel that misses the point, however. Given the software's ability to calculate to double digit decimal places (I have seen 14 places displayed, though I am unaware of the internal number), I would feel that this simple calculation would be a slam dunk. Excel and calculators are necessary for many tasks, but this should not be one of them.

[CGBenner]

@gregory_nickol @b.mccarthy @jan_priban 

I just tested this in 2022.2 with a table where length units were set to mm.  The frctional value calculated as expected.  After changing the column properties, units to in... the fractional value calculated as incorrect like Gregory shows in his images.

[jan_priban · Accepted solution]

Hello all,

thank you for detail explanation, we are sorry for this issue. Yes, for inch / imperial column type it is reproducible. This issue is tracked in our tracking system as the INVGEN-60998

So far (until issue gets resolved) use please workaround with Excel: Content Center Family table has a function "Edit via SpreadSheet" that load entire / complete family table into Excel. But you do not have to use this "Edit via SpreadSheet" function, just in Excel create one column, type fractionals  in Excel like "=11/32" ... and copy paste Excel range into Family table cells range (= manual Copy/Paste from Excel to CC family table, click first cell in Length column in CC family table and CTRL+v)

Thank you

Jan Priban

[CGBenner]

@jan_priban 

Thank you for testing this internally and confirming the issue.  Also, thank you for the workaround.  It's a few extra steps, but maybe it will help users move forward until the fix can be made.