SU doesn't recognise fractional inches (e.g., 1/2") as an imperial measurement when units are mm


I thought that SU would recognise imperial units (feet, inches and fractions) in the Measurements box, even if model units were set to mm.

It doesn’t recognise fractional inches. And no, I’m not using curly quotes.

Drawing in mm with two decimal places, I tried to push-pull 1/2" (where I type in the 1/2" characters. I get 0.5mm instead.

if I type in 0.5", I get what I expect - half an inch or 12.7mm.

This seems to me like a bug, or at least behaviour I don’t expect.

It seems also to be true in SU2016 as well as 2017, both on Mac.

Does it also happen on Windows?

Am I just wrong in my expectation? If so, why?

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The measurements box doesn’t perform calculations.
The only one it seems to do is simple divisions, provided that you use the same units as the current setting: 100/2mm when in set to mm —> result 50mm
Or 20/5" when set to " —> result 1’ 8"
Don’t expect any other calculations (yet, requested many times by many users).


Maybe 1"/2 works.


Yes, works the same under Windows.

Basically fractional (division) input only works for current model units.

No this does not work on Windows. Nor does using any from of bracketing.
All result in a “Invalid length entered.” tooltip.

In your case, the opposite works better. Ie, setting units to Architectural (or Fractional) inches, entering inches as fractions into the VCB, and entering metric lengths like “7mm”, “5.04mm”, etc.


I wasn’t so much expecting it to do calculations, just do what it does when you input imperial dimensions. I haven’t (but will) see what happens if I try 1'1" - not at computer at the moment but will try later tonight.


This works fine because there is no fractional division going on.


I get confused behaviour if I use something like 1’3 or 1’6 when units are set to mm.

A line set to 1’3 long comes out at 307.8 mm - one foot, plus 3mm.

1’6 becomes 310.8mm

10 1/2" becomes 10.5mm

1’ 3 1/2" becomes 308.3mm - one foot plus 3.5mm, in spite of the " (inch) mark.

I think this is just a muddle. It recognises the unit characters (foot and inch marks, separately) but ignores a mixture of the two in a bizarre and confusing way, treating anything after the first mark as if no units mark is later appended*.

While this may be sort of logical, I think it is wrong, or at the very least, half-hearted and confused.

Surely it should either say ‘invalid length entered’ or calculate it properly. If you aren’t paying full attention, and just type in the value and get no feedback, you’ll THINK you have entered a valid and correct size, but it will be in mixed units and wrong.

And can’t see that it would be difficult to fix. There must already be a function to calculate decimal inches from feet, inches, and fractions: why can’t it be invoked whatever the user units are set to, by the code that parses lengths and treats some as invalid? The input is ‘valid’ as in meaningful, just calculated incorrectly.

[*Note from above. It does NOT ignore the inch mark if there is no fraction, I now find]

It’s even more confused than I thought.

As I said above, 1’3 is treated as one foot plus 3mm.

But 1’3" comes out at 381.0 mm = 15 x 2.54mm.

This is even more bizarre than I thought.

I’d call this a bug, however long standing it may be.


I agree and think most of us have agreed in past threads on this.

Nay. It is confusing and definitely needs some love. It is not what any user would expect.

I also am not sure if this has always been a bug or introduced when other things were fixed.


Sorry, I was guilty of not searching for past threads first - I got so irritated by the behaviour I just let off steam! I’ve never directly noticed it before, and in over a year’s worth of reading almost every thread on this forum, don’t remember seeing anything like it mentioned in that time - but it may be a much older bug: I verified it only in 2016 and 2017 on Mac.

Has it been acknowledged and ‘formally’ recorded as a bug?


Also, typing 1’1/2" doesn’t work - it adds 0,5 mm to the foot


Yes, I found something like that too. It’s a right muddle. And SHOULD be easy to fix - the code to interpret lengths properly exists in Imperial unit models, so it can’t be difficult to add or adapt for metric unit models.


I was referring more generally (as Wo3Dan did) to long standing requests about the VCB’s behavior, quirks and shortcomings.

I’ve been involved heading toward 10 years now, in at least 3 official SketchUp forums and 2 editions of SketchUcation. There have been numerous complaints and requests (over the years) with regard to how the VCB (Measurements) control works, and doesn’t.

No problem, you’ve explained the issue quite well, and better than most could.

Well more than likely, the other threads are in the general SketchUp topic where it’s just a normal question on how the VCB works or reads units characters. We tend to accept it’s quirky behavior as it is the way it was designed, so is not exactly a “bug”.

It might work to say it’s another Feature Request for the VCB ?



The designer was having a seriously ‘off’ day, then!


I’m on your side. But the mode of operation in the past for SketchUp development, is that a “bug” is something that is unintended. I have had several bug reports rejected over the years, because the issue was working as intended (or the way the programmer wrote it.) No amount of arguing that the feature should never have been designed that way, has gotten the report accepted. Usually I’ve had to resubmit the “issue” as a feature request to change the feature’s behavior, and sometimes I’ve just let it drop as I didn’t wish to waste any more time on it.


You have more experience of the way the design team respond. I still think it’s a bug, and a rather nasty one.

Is it worth reporting at all? Has this particular issue, rather than general ones about the Measurement box, been raised in this way before to your knowledge?


Works with 1 1/2 , make sure have space between unit and fraction.


I cannot say for certain, because the database is only accessible to Trimble employees.

So a SketchUp Team member will have to chime in.

I would say so, and that you have done so with this thread.


I think perhaps you triggered it with the reference above to Bryce Stout (@Bryceosaurus). Thank you.


I’m pretty sure you were around when we released V-Ray for SketchUp 1.0 weren’t you? That was 2007, so that would be 10 years already.


Thanks for the report. I filed a bug - SU-36745