dimensional bit rot

[btrusty]

Revit 2008, 2009 (havent done a project in 2010 enough to experience this problem)

has anyone ever noticed that after working on a project for 3+ months (estimating as this is when it occurred on my current project, but have had it happen before on projects that i have been working on for a while) that some dimensions do not make sense?

e.g. you have a chain of grids that show 50' - 0" even, but the dimension of the first and last dimensions is 250' - 0 1/256" (this is a problem for any element type - grid, line, wall, window, door, etc)

this is using a dimension string for
"Units Format" rounding "nearest 1/256"

this becomes a problem as i am sometimes able to fix it and sometimes not able to.

[fixes]
if i move some of the grids back and forth randomly (not typing in dimensions) then move it back so that it snaps to another object (3d modeled component, drafted line, etc) it will fix and all lines will then shown up correctly. from the example above, each pair of grids still show 50' - 0" and the overall dimension then shows 250' - 0"

[not fixes]
i attempt what i did before, but regardless there is always a 1/256" dimension wrong.

at first i think its just the dimension is to the wrong item, but when i do it again in another view and or creating a new view string at the same or different scale. and this is done with "thin lines" enabled (or as i call it "no line-weight" so its not like i am accidentally clicking on the wrong item time after time.)

***

does anyone have this problem or am i just crazy?

if you need a picture of what i am talking about, i can attach it.

thanks,

[patricks]

Not sure if I've seen that, but I have seen a dimension with the exact same value on both sides of an object not switch to the EQ display, no matter what I did to try to type in values. Values were both the same, down to the same */256 and still no EQ.

I have also seen a joined roof do crazy things because it was LESS than 1/256" difference in height from the main roof.

[truevis]

...e.g. you have a chain of grids that show 50' - 0" even, but the dimension of the first and last dimensions is 250' - 0 1/256" ...this is using a dimension string for "Units Format" rounding "nearest 1/256"...

Patient: My head hurts when I bang it on walls
Doctor: Stop hitting your head on walls.

Perhaps set your dimension rounding back to 1/16".

If you require a building to be built to +/-1/256" tolerance, you may be paying too much.

Revit does not seem to be designed for close-tolerance work. I think it's a performance trade-off.

[patricks]

Patient: My head hurts when I bang it on walls
Doctor: Stop hitting your head on walls.

Perhaps set your dimension rounding back to 1/16".

If you require a building to be built to +/-1/256" tolerance, you may be paying too much.

Revit does not seem to be designed for close-tolerance work. I think it's a performance trade-off.

Many people here keep the dimension rounding to the smallest amount to try to make fractional dimensions of odd amounts readily visible and corrected.

Our office holds the philosophy of having as few fractions as possible on our drawings. We dimension to edge of slab/face of core on exterior walls, center of stud on interior walls, or to one side of block walls, and we do our best to make all dimensions an even number. If anything is out of whack, the discrepancy is readily visible.

Of course it won't be built that exact. But computer drawings do have that high accuracy, and so accurate, even dimensions should be something everyone strives for whenever possible.

I personally can't stand drawings that dimension 4 7/8" walls as 5" walls, and 7 5/8" CMU walls as 8" walls. It's so annoying because dimensions will NEVER add up across a building when dimensioned that way.

[truevis]

This is a tip that may help: If you try to move something a very small amount, you'll get an error like line is too short. Solution: to move something 1/256" to the left, move it 1" to the right and 1 1/256" back to the left.