# Measurement unit tolerances

I constantly toggle between architectural and engineering units in the model info / measurement units tab. For architectural, I use 1/16" display precision and engineering to two decimal points. I see no way to set these parameters - when I change to engineering from architectural, it starts as 4 decimal places and I need to select 2, then when I switch back to architectural I always have to change it from 1/4" precision to 1/16".

It sure seems like there ought to be a way to set these display tolerances to a default. Maybe there is, and I just havenâ€™t found it. Which is what Iâ€™m hoping someone here may know.

Any ideas?

Thanks!

Bob

What difference does the Display Precision make to your modeling? This has nothing to do with measurement tolerances. Only how precisely the dimensions are displayed. Having four places beyond the decimal doesnâ€™t mean you have to type all those extra zeroes. Higher display precision can help you identify discrepancies and errors in your model, though.

1 Like

All of the architectural plans I work with display dimension to the 1/16 and elevations to 2 decimal places. With my feeble old brain, I just find it easier to maintain those protocols in my model when Iâ€™m measuring something or determining elevation. It just seems to be a natural parameter to be able to set in the model info tab - or somewhere

As Dave noted, the unit and precision only matter in the display, in the input you can include any unit you want.

I completely understand that. It is precisely the display that I want to control, not the precision.

I do this 50 xâ€™s a day, maybe more.

Dave has already pointed out that the â€śunitsâ€ť in SketchUp only affect display precision; they have no effect on the actual values. That said, I understand your point. I think what you observe results from the way SketchUp captures units internally. The base (2 or 10) is one value, and the exponent for the fraction is a second value. So, 1/16 = 1/(2^4) has base 2 and exponent 4, .0001 = 1/(10^4) has base 10 and exponent 4. When you switch units, the base changes but until you select a new exponent, the old one carries over.

I think it would not be hard to write an extension that would track your selection of base and automatically switch the exponent to your preference, but Iâ€™ve not seen one.

Edit: I suspect it was originally done this way because in most cases the same exponent for both bases provides the closest match in visible precision. That is, 1/2 needs one decimal point, 1/4 needs two, 1/8 needs three, etc.

By the way, top oâ€™ the morning, Dave (& Cotty)

1 Like

Top of the morning to you, too, Bob. And HNY!

In the same model or different models? If different models, why not set up two different templates. One for Architectural and one for Decimal units.

Does it matter while you are modeling if you have a dimension displayed in the Measurements window at 2.6250 instead of 2.63? If you are adding dimensions to the model you could make that adjustment then. Personally Iâ€™d prefer to see 2.6250 if thatâ€™s what the dimension really is. Iâ€™ll reduce the display precision in dimensioning when I create the dimensioned drawing.

In the same model. And I donâ€™t produce dimensioned drawings, generally speaking. When I check dimension in the plan to the model, to check accuracy, if the plan shows me a dimension to the 1/16 (which, frankly, is sloppy work on the part of the architect because framing is generally not done to the 1/16), to check that measurement in the model to 1/4, doesnâ€™t show me quite what I need to see. If the plan dimension shows me a dimension to feet / inches / 3/16", then seeing that rounded to 1/4" when I measure it in the model, isnâ€™t what I need to be seeing. I need to see that 3/16.

Iâ€™m sorry, Bob. Iâ€™m having a hard time following. I guess if I were looking at what you describe I wouldwant display precision set as high as it would go for the units Iâ€™m using. So for Architectural I would have Display Precision set to 1/64". That doesnâ€™t mean SketchUp will display 3/16" as 12/64" but if the dimension shows as 7/32" I can figure out if itâ€™s supposed to be 3/16" or 1/4". With Display Precision set to 16ths that wouldnâ€™t show. Of course being out by a 32nd might not be an issue but it could contribute to a cumulative error that is an issue.

The issue is less the display precision and more having to reset it every time you switch between architectural and engineering.

As I play around with it more, I see that it is that Iâ€™m using different display precision values between architectural and engineering. Switching between the two, I notice now (after years of not noticing this) that 1/16" precision in architectural display correlates with 4 decimal places in engineering display. So, I could leave the engineering precision value at 4 decimal points and then the architectural will return to 1/16.

See, all of that conversion between 16ths, 32nds and 64ths you did up above - ya I canâ€™t do that in my head. If Iâ€™m looking at a read out in the model of x/64, I canâ€™t just translate that to 16ths in my head, but 16ths is what I need to see to relate it back to the dimension shown on the plan.

I can see now that I can change my work flow to leave the display precision of engineering to 4 decimal places and Iâ€™ll always return to 16ths in architectural. Rounding 4 decimal places to 2 IS something I can do in my head.

I suspect that may just be word salad to everyone but me! Ha!

Thanks for the conversation, Dave. As always with you, I learned something new!

Talk to ya next year some time, Iâ€™m quite sure! Happy New Year!

2 Likes

Gotcha.

Iâ€™m not saying thereâ€™s anything wrong with what you are doing but I must admit I have a hard time dealing with coarse display precision when modeling. Iâ€™ve seen too many cases where a little bit of imprecision can be a problem. How wide does the scribing board have to be to make four cabinets fit an 8â€™ wide alcove if each of those cabinets is 24-1/32" inch wide? Of course I know byt the time the walls are framed, sheetrocked, and painted there wonâ€™t be 8 feet to work with anyway.

Take the rest of the day off and enjoy New Years Eve.

Haha! No rest for the wicked. I think Santa was generally displeased with me this year!

You know, too, I keep forgetting that youâ€™re modeling cabinetry and the like. Definitely want more precision there than in structure. Hell, weâ€™re lucky to get things within an eighth in the field.

1 Like

Might this be what you are looking for?

I will check this out. Looks a few years old without updateâ€¦ maybe it still works