Dimensioning to 1/8" Accuracy?

[mcqueenhomes]

The 1/8" accuracy doesn't exist in the field. The pencil the carpenters use to mark where stuff goes has got to be 1/8" thick just by itself.

Not to mention the pressure to get it done and get paid, the 1/8" isn't worth it.

No buyer has been known to measure the rooms to the 1/8".

If you buy a manufactured home, you're lucky if the windows and doors are in the right place.

In fifty years, the building will start to unsquare and it won't be perfect anymore anyway.

I've never built a house (everything I know comes from growing up watching This Old House), but I perceive the rockers cover up the inacuuracy the framers left. Then the finish carpenter covers up the inaccuracies the rockers left. It's the historical basis for base, crown, and casing as we know it.

[frwillia]

Originally posted by WendyWelton
Those of use who do a lot of plans for remodeling have to deal with old chunks of buildings - where measuring to the nearest 1/16th is an exercise in futility anyway. When you do a gut renovation of a 200 year old house, that you had to measure with all the walls still in place, you really do need to give the guys a "+/-" at strategic points, so they know where they have some play and where they don't. Hence my desire for the ability to append things to the dimensions, and not have to go chasing text fragments around when I move a wall.

Wendy,

Good point! I've not done a remodel, only new construction. Thinking back to when Mom and Dad made some changes to the 200 year old farm house I grew up in that was built with 2" x 4" rough cut lumber that measured 2" x 4" and square nails. I remember seeing lots of furring strips and cleverness trying to get a modern window to fit in the old framing.

I really like the idea of having total control of how the dimensions display.

Oddly enough, in the starter houses I draw, the really accurate dimensions are much more important than in the larger custom houses. These starter houses are houses that were being built before the code arrived in PA last year. My contribution is to create plans for them that meet code. Increasing the walls to 2x6 framing, converting the stairs to meet code, etc. have all changed the size of the house by a few inches here and there.

Over the last year I've found that I need to spend time with the foundation crew - I put quite a bit of effort into the foundation plans so that they can get that part built accurately and square. I work hard to try to get foundation dimensions to come out to even inches. Then I go over and we check all the stakes and forms together to be sure it is right. The framing crew will build the house on top of the foundation - where ever it is! If the foundation is right, the rest of it is a whole lot easier to get right.

The excavating/foundation crew and I have worked together to get a system for dimensioning that works for them. I usually print them their own working drawing that is dimensioned differently than the permit version - lots of diagonal measurements on it so they can check for square. The diagonal measurements come out in odd fractions.

Fitch

[WendyWelton]

Fitch,

Another good point - and another reason we need the ability to append firmly to dimensions. Very seldom do we get to spend the time you spend the foundation crew. Combine that with the inherent difficulty of getting fat stakes and reused plywood forms to produce a perfect foundation - and you get what you get. When I measure an existing house for a remodel, I don't care if it was built yesterday. If the plans say 24'-0", it might be 24'-1 3/8" and it might be 23'-11 1/2", but 24'-0"? Almost never. Then the framers build on that. They can correct a little, but it depends on how far off it is. And, as Jason said, the pencil line they mark the wall layout with is a solid 1/8".

Also - when you need to space things equally, sometimes you end up with 1/16" increments. The ability to append "=/- (EQ)" or EQUAL to the dimension text would tell the builder immediately why the $*#)%& is giving such foolishness to a guy with fingers like treetrunks.

Here's some questions for everybody.

1. If we were to get the ability to append to a dimensions - would you want to type in anything you want? Or, would you want to pick from a list (would ensure spelling and consistency)? My list would include:
+/-
VIF
EQUAL
EQ
+/- (EQ)
EXIST
HOLD

What do other people use?

2. Would you like the ability to replace the dimension numbers with "EQUAL"?

3. How about this - You know how sweet the little Center button is, that lets you center a window in a room? How about if we could have an Equal button? You'd pick your 3 or 4 windows, select the Equal tool, then pick the dimensions you wanted made the same. It would keep the outermost points of the dimensions fixed and redivide the selected dimensions equally.

If you selected dimensions outside the windows, between the windows and the walls for instance, it would make equal spaces between the windows and between the windows and the walls.

If you selected the dimensions between the windows only, the outermost windows wouldn't move, only the ones inside. Combine this with the choice to either append to the dimension text, or replace it with EQ or EQUAL, and you'd have an amazing tool.

Wendy

[lavor]

_______________________________________
The 1/8" accuracy doesn't exist in the field. The pencil the carpenters use to mark where stuff goes has got to be 1/8" thick just by itself.
_______________________________________

As the old adage goes...

"Measure it with a micrometer, mark it with a chalk and cut it with an axe."

That is how all residential construction is done

[alobartn]

Wendy,

Your point is well articulated. EQ is something I use frequently, but it's really a pain to get the EQ letters EQ. I created a custom line using it, but depending on the scale and the zoom, it's always different. Usually I just draw a line and insert text over it to ensure it's in the center of whatever I'm dimensioning. I love the drop down list idea. Brilliantly simple, or so it seems to a non-progammer.

[Ron Ravenscroft]

The problem is that even after you adjust the model Chief sometimes decides it does not like the dimensions and automaticly adjusts bqak to 1/16 or 1/8 depending on your settings.

[ebdesign]

1/8" certainly DO exist in the field! Even from the lumber yards. Put your tape on an 8' 'pre-cut' stud. It measures 93 5/8" exactly. That's why 97 1/8" is used for plate hgts, not 97". w/ chop-saws used for cutting 2x's, you make your mark, & leave it/take it w/ the blade. That's the way I was taught even w/ the old Skil saws.
The closer to finish work you get , the smaller the dimensional tolerance- even down to 1/32"s. Abybody that's done any finsh work, cabinetry, etc will agree w/ that.
The original point of all this was how to get dimensional accuracy w/ Chief. If you use 1/16", your dimension strings will add up (no rounding to an 1/8" or whattever you have it set for), & you can use direct entry to eliminate just about all fractions- if that is your preference. It certainly is my preference. (Chief actually rounds off 1/32"s to an 1/16"- that's why you ahve to use the 'micro-move tool oaccasionally).
JMO
Jim

[Tim O'Donnell]

I agree with you Jim...as builder I most certainly do use 1/16" dimensions, even when framing...and as you state, even tighter when cabinetry is involved

[spencerdesign]

I agree too, Jim. Everything you said is spot on, from my experience.

Sam

[WendyWelton]

I do 1/2" for concrete, 1/8" for framing and drywall (type X is 5/8", as is blueboard and skim coat...), 1/16" for cabinetry, 1/32" for custom metalwork. When I do high end jewelry store cabinets, my details get sent back to me with a few added notes as "shop drawings", and we really do account for the thickness of veneer, the finer tolerances of custom stainless work, etc.

If you read through Masterspec you'll see that the allowable tolerances for concrete work and for structural steel doesn't even come close to 1/16" accuracy. I defy anybody to find wood studs these days that are straight and true enough to get 1/16" accuracy in the finished product.

Nobody is saying 1/16" doesn't have it's place. I'm saying that for certain building types (and certain Builders - I don't get to pick 'em), it's not appropriate. I'd like to have the option to take the 1/8" rounding, that we already have, and display it as the full fraction. That's all.

And, I'm not having a cow over this one - I'm merely in favor of this request. I'm not quite sure I understand why anybody would object to adding this option. Those who don't want to use it wouldn't have to.

[spencerdesign]

I have to say that I did an add-on for an Architect a while back and I would describe the shape of the footprint as being like the stock of a rifle, a very odd shape. I had a stray 1/16 I just simply could not iron out. Could of used the 1/8 then if it showed the fraction. I agree that 1/16 has no place on the plans, unless you like being chuckled at.

It baffles me as to why the program allows us to draw at a level of accuracy greater than that of the dimensions. Could this possibly have any applications? If your snap is set to 1/16 then your dimensions should follow same IMHO.

Sam

[alobartn]

I agree that 1/16 has no place on the plans, unless you like being chuckled at.

I'd have to disagree. As a former GC, I had no qualms with 16ths if that's what the designer wants. Especially in situations like the one below, but really for any kind of remodeling it can be necessary.

[spencerdesign]

Adam,

Perhaps it has it's place. To each his own. It does, however, look as though you could have adjusted those radii up or down (in the x or y) to the nearest 1/8 without compromising the design, but I don't know your circumstances. Considering field tolerances, it seems futile to me to design to the sixteenth. As a builder/finish carpenter I am used to cutting to the 1/16 or less to meet actual field conditions, but that is different.

Sam

[Yeksaldj]

Having been "in the field" for many years, I totally agree with Sam. Ordinary residential construction practices make anything less than an eigth ludicrous, at least through the framing stage. I spend much time trying to eliminate unrealistic dimensions from my plans.

I long ago created a little symbol something like this --
<--EQ|EQ-->, and I'm not afraid to use it for windows, etc.

Ever hear an old plumber say, "There's only 4 marks on a tape?"

Or a sheetrocker on a scaffold holler out to his cutter below, "7,6, and 3", which means 7 feet, 6 inches, and 3 eighths?

Residential framers will snap out a gable wall on the platform. Well, there's a quarter right there, and that's on a calm day.

These are not incapable people; they simply understand the limits of accuracy in the field. I consider it part of my job as a designer to not saddle them with absurd and unnecessary numbers. I just hate to hear that snicker, I guess.

If it takes a little longer to go through a plan and simplify the dimensioning, it's worth it. Ya' ain't buildin' a piana ya' know. If CA wants to simplify the process and improve the controls we have in that respect, I'm all for it.

In special situations, cabinetry, high end millwork, etc., of course it's a different story. But even there, I use sixteenths only as a last resort. The long-standing enmity between designers/architects and builders notwithstanding, I figure we're all on the same side, and I want to give the builder as simple and buildable a plan as I can.

[ebdesign]

Wendy,
I'm in total agreement w/ you as far as giving us some options to add/overwrite the actual dimension.

Jim

As far as the 1/16"s go, I would think the drawings should be as accurate as possible w/ no tolerances. After all, if the drawing is w/in a 1/2" for concrete, & then the form carpenters call 1/2" "close enuff" of that, close enuff, close enuff,..........pretty soon, we're standin' in the next county.