Actual vs. Nominal

[NHURLEY]

I work for a firm that is relatively new to Revit and we are currently setting up our standards. In the past we have done a majority of our jobs using nominal dimensioning. I have done one medium sized job in Revit using nominal and I am convinced that actual is the proper way to go for Revit. However trying to convince them that we should be using actual for our Revit standards has been an uphill battle. Anybody have any thoughts or experience in regards to this situation. Any insight on this would be much appreciated. Thanks.

[matt_dillon]

Why are they married to nominal dimensions?

If the answer is "because that's the way we've always done it", then they're WRONG. That's not a valid reason.

If there's a benefit at all to nominal dimensions, then get them to tell you what it is, otherwise, I can think of no reason to use nominal in a building modeler like Revit and every reason to use actual dimensions.

[Dimitri Harvalias]

Keep it 'real' man;)
Actual dimensions are the only way things should be done.They are what they are.

[dgreen.49364]

I believe that the use of nominal is a left over from the pen and paper days when dimensions were calculated by hand. With todays hardware and software, using nominal makes no sense.

[gwnelson]

You can set the tolerance of any dimension - I keep sets at 1", 1/2" & 1/8". Covers everything I could expect from a guy with a hammer.

[WYSIWYG]

Go actual, it forces you to be more accurate. And I love no more over ridden dimension that caused problems down the line because some tried to "fudge" things.

[Steve_Stafford]

Nominal during schematic design seems reasonable but after that...actual makes more betterer sense.

[rjcrowther]

I use nominal dimensions at times in Revit.

The circumstances are usually either:
- leaving it up to the builder to a certain extent
- the builder has no hope of acurately building to the drawings and instructing them to the millimetre is pointless (curved walls in brick meeting a pitched roof and describing the distance of window lintel to wall plate)
- I want my fee and am sick of having the customer stuffing around so nominal is good as it completes the drawings.
- giving the builder a tolerance.

When I do this I like to have an accurate model (accurate to my thinking) and then draw over details to produce the 'nominal' bits.....I need an accurate reference when I get a phone call asking how big something should be in theory.

Thanks,
Rob

[Adam Mac]

Well said - at the end of the day the reality is that there is still a requirement for the "occasional" nominal dimension - when and where they get used is my decision.