Project tolerences vs dimesion tolerences

[Anonymous]

Hi Guys.

A long time ago when I was @ training in Boston for v.9 our instructor had mentioned something about the tolerences of a project vs the tolerences of dimensions.

It seems to me he had said you want your drawing tolerences to be rounded to a smaller fraction than your dimensioning tolerences.

We have run into problems where we have dimensioned a wall with windows in it. And then we have an over all dimesion string. If we add up all of our pecies of dimenions it does not equal our over all dimension. by something small, like an 1/8" or so.
So, to fix this . . . ?

I guess on this project in paticular we had our dimension tolerences set to 1/8", and our project tolerence was 1/16"

So we were drawing to an accuracy of 1/16", and our dimensions were rounding that to an 1/8 of an inch.

I do understand that that is NOT accurate enough to begin with.
We have since changed our tolerences to: Project - 1/64", dimension - 1/16".

So. . . I guess what I am asking is what do you guys typically set your tolerences to?

[Link]

Jesikuh123 wrote:
So. . . I guess what I am asking is what do you guys typically set your tolerences to?

I just about always dial (imperial) tolerances right in to 1/64" for both project preferences and dimensions. It gives you the highest degree of accuracy and if you model accurately, it will round up anyway and not be an issue. For metric I dial it in to the nearest (whole) mm.

Cheers,
Link.

[Erika Epstein]

Link wrote:
I just about always dial (imperial) tolerances right in to 1/64" for both project preferences and dimensions. It gives you the highest degree of accuracy and if you model accurately, it will round up anyway and not be an issue. For metric I dial it in to the nearest (whole) mm.

Cheers,
Link.

I keep tolerances like Link outlined. If you are a sloppy modeler your dimensions will give you away

[Link]

Erika wrote:
If you are a sloppy modeler your dimensions will give you away

Exactly!

And so it should!

Cheers,
Link.

[David Maudlin]

Jess:

For what it is worth, I have set my Project Preferences > Working Units to feet & decimal inches to 3 decimal places. I have gotten used to inputing fractional inches as decimals (this is faster for me than using fractions), and this shows modeling inaccuracies very easily. The Dimensions are set to feet & fractional inches so the contractors don't go nuts (and yes, the advantage of a metric system is obvious, but I don't think that is happening in the US in my lifetime).

David

[Anonymous]

Your right David, no metric in US residential construction in our life times.

And on most US residential construction sites you'd get trampled for metric.
Or worse yet, some yahoo would lock a metric supporter in a port a potty and dip it over.
And your right metric is easier if your born into it or used it as I did as a biology major, but this is sacred ground for the US construction industry...so far...
Bier
ps,
Don't get using decimals, they don't round up even in my book.
Like 3/8" does not have easy decimal equivalent.
And in say algebra, fractions are less messy.
If you don't mind/ I'm curious,
how does that work for you?
Or maybe you just use, say .125;.250;etc?
Thanks

[David Maudlin]

Bier wrote:
Don't get using decimals, they don't round up even in my book. Like 3/8" does not have easy decimal equivalent.
And in say algebra, fractions are less messy.
If you don't mind/ I'm curious,
how does that work for you?
Or maybe you just use, say .125;.250;etc?
Thanks

Bier:

As I said in my earlier post, this is about the Working Units (what you see in the Coordinates Palette, Tracker, dialog boxes, etc), not the Dimensions (what is displayed for dimensions strings, window schedules, etc). I have just memorized the decimal equivalents for 1/8” increments (1/8” = .125”, 3/8” = .375”, etc) and this is how I input these sizes for drawing elements (length of wall, height of window, etc). I very rarely need to input anything finer than 1/8” sizes.

There are for me a couple of advantages: 1. I find this faster for keyboard input than fractions as I generally use the numeric keypad on the right side of the keyboard, and 2. (which is the point of this thread) very small inaccuracies show the in the Coordinates Palette (down to 1/1000 of an inch) as opposed to 1/64” of an inch. I have found this exposes model inaccuracies that the 1/64” (or larger) setting can hide until a problem, like the one Jess described at the start of this thread, appears.

Just my 2 cents, so lock me in that port-a-potty and tip away 😉

David

[Anonymous]

Thanks David for the great decimal explanation.
I see why now.
My silly, too late to think, comment about port a unit, (besides, it was holloween night), was in regards to metric not meant to reflect on your decimal concept.
Sorry if I implied that.
Take care
Bier

[David Maudlin]

Bier wrote:
My silly, too late to think, comment about port a unit, (besides, it was holloween night), was in regards to metric not meant to reflect on your decimal concept.
Sorry if I implied that.

Not at all, I understood your comment to be about metric on site, just having a bit of fun at my own expense.

Cheers,

David