Dimension Round-off Problems - you must be kidding

[Alex Page]

As documentation manager, my plebs will laugh and laugh and laugh at me (and never take me seriously again!!) if I printed out one of my sheets with a dimension round-off problem...refer jpeg....
If I move the wall abit one way, the other dimension changes......yikes!

Im sure I can fix it, BUT I didnt envisage getting out my calculator and checking all the dimensions thoughout the project for every project in the office!!!!!!!!

Yes, they both go to the grid line
Yes, they were created in 'one go'

Anyone else had this problem?

[Phil Read]

Alex -

While in this view set your Project Units to round to 1 decimal place. You'll see that Revit is rounding up for the inner dimensions - but rounding down for the overall dimension (see attached).

And most importantly - and you're not in violation of altering the time/space continuum.

All the best -

Phil

[LRaiz]

Does not this picture indicate that modeling is done in a sloppy way and most likely objects themselves need to be moved? Fortunately you don't need to fake dimensions in Revit. While in modify tool you may just pick questionable grid lines and walls; existing dimensions will highlight and reveal accurate values before rounding. Then you can type the true value that represents design intent and object will adjust accordingly. Usually Revit avoids getting users into this kind of situation by snapping to round values during sketching but in certain cases user may override snapping and later be surprised by accumulation of roundoff errors.

[Alex Page]

yeah, realise this, but since revit dims to the model and you cant fudge it, it is still a problem......Ok so sloppy modeling creates this, so I need to check ALL projects in the office. Is this case its obvious, but what about running dims over a whole wall?

[LRaiz]

Generally you don't need to check everything. Revit does snapping to rounded numbers when placing objects in the first place. One thing to watch for is that users do not turn off snapping.

See Settings | Snaps... dialog. If Snaps Off ckeckbox is not checked and Length Snap Increments checkbox is on then you should be able to avoid problems of not round dimension on placement.

[jbalding48677]

Ok so sloppy modeling creates this, so I need to check ALL projects in the office.

No offense here, so please don't take this the wrong way, but yes you will need to check ALL projects in your office if you have "sloppy" modelers. The point is that if you need accuracy to to 1 millimeter then the person responsible for modeling, drafting etc. needs to be aware of that, and be more careful.

I would also point out that sloppy AutoCAD, miniCAD, versaCAD and even Excel work will give you the same problem.

[Alex Page]

No offense here, so please don't take this the wrong way, but yes you will need to check ALL projects in your office if you have "sloppy" modelers. The point is that if you need accuracy to to 1 millimeter then the person responsible for modeling, drafting etc. needs to be aware of that, and be more careful.

I would also point out that sloppy AutoCAD, miniCAD, versaCAD and even Excel work will give you the same problem.

Yeah, I completely agree, I guess its just easier to change AutoCAD dims...dont get me wrong thou...NO WAY will I go back!

[Martin P]

We had a joiner wanted us to show dimensions to one decimal place (plasterboard is 12.5mm) , that is the other option!

[Wes Macaulay]

Yeah, I completely agree, I guess its just easier to change AutoCAD dims...dont get me wrong thou...NO WAY will I go back!Ah man - no way! Click on the object to which a dim is snapped, and re-enter its value. Done like dinner. Ye no kinna do that in AutoCAD...

And if you want, set your project units to very high accuracy, and then all your temporary dims that appear when objects are selected will tell you if there's any non-rationalised dims.

[aaronrumple]

We use two dimension families. One for rounding to 1/8". The other called Exact. We can quickly grab all the dimensions - change them to exact. Do a QA/QC and then change them back.

[sbrown]

What you really have to worry about is cumalitive rounding errors, I highly recommend modeling with the exact dimension style as aaron suggested. If you are 1 mm off repeatedly in a long building your overall will get screwed up, I've spent hours chasing this kind of problem down in autocad and in revit. It is even more important when it come to angles. If you are slightly off 90 you will have problems with interior elevations and sections. I can't even count the number of times I've had to put angular dimensions on every wall to find out which was slightly off and then the next one went perpendicular to it and so on until you have a chain effect of walls slightly of 90.

This typically gets started when you trace a poorly constructed autocad background.

[Alex Page]

We had a joiner wanted us to show dimensions to one decimal place (plasterboard is 12.5mm) , that is the other option!

he didnt want plaster/ paint 0.5mm included??!