Friday, November 11, 2005

de-Value Engineering Dimensions

We can’t override dimension values in Revit, by design. Nevertheless we covet the ability to do so. The images below are a few examples of what I consider legitimate reasons to be able to do this. Information that looks like dimensions but conveys different data than conventional linear, angular or radial values.

So how did I do all of these in Revit? I used a font that has been stripped of all the symbols it had, rendering it blank. Placing a dimension that uses this font means there is no value, nothing, nada…to see. Then I just placed some text above the dimension line.

Ouch!! A cursed workaround no doubt! But in the end it is what we need, something that sure looks like a dimension but isn’t. Or is it? Of course it is still a dimension. Picking the object the dimension is referencing will still allow you to change the objects position by clicking on the blank field to enter a new value.

Another way to do this is to setup a dimension style that uses a much smaller text size so it is easily hidden by the text you place over the top.

Remember that each dimension style can use its own rounding and formatting rules or the project settings. By default they use the project settings. The dimensions for the cabinetry above that show just inches are an example of such an override.

Here’s a bit of the OP part of OPED…

On several occasions I’ve suggested that Revit simply provide us with a tool that places annotation that happens to look like dimensions. It does not manipulate geometry as real dimensions do yet could adjust to reflect changes in geometry so the annotation remains aligned with the references that were picked originally. The information displayed would be entirely up to us. In fact nothing would appear unless we did enter something.

That said, this is a bit of a “slippery slope” since a user could dimension a project with this tool instead of with real dimensions and create a potentially horrendous situation both from a liability and workflow view. Simplistically we can blame that on training, but we are responsible for the situation since we’ve asked for it, invited it even.

What are we after when we say we need to override a dimension value? Well, some are suggesting that we should be able to type in whatever we please. I prefer that this not happen. The trustworthiness of information is all we have. If the information isn’t trustworthy, we won’t trust it, use it or profit by it.

When we tout the virtues of building information modeling yet argue to undo the inherent integrity that Revit offers we risk chopping off our own fingers!

An example of this is the Reference Other View feature.

We all clamored for this, argued passionately for it and then got it and now wouldn’t give it up. Yet, what happened as a result is the inherent integrity of no view being incorrectly identified was compromised. No longer can we look at the detail bubble and know with confidence that the detail we find is the one we wanted to show within our set of documents. Sure, there will be a detail exactly where we said it would be, but it might not be the right detail because I picked the wrong one from the list. At least true for symbols that carry the mark SIM, OPP or TYP, assuming we make sure to use them. If we don’t, then all bets are off.

Sometimes we need to be careful what we ask for.


Shaun van Rooyen said...

Hey Steve!
Still checking out your great blog.

So is Cad Digest

Thought I would let you know

Steve said...

Thanks! Glad you enjoy it! Nice to see the addition of yours and Mike's You all have a lot of success stories to share.


Anonymous said...

G'day Steve....
Have been following your BLOG for a while and enjoy it - keep it up!
I whole-heartedly agree that we need an "annotation" type dimension - REVIT should provide the option and let us make the decision as to how it's used. I'm a grown adult who makes lot's of complicated decisions every day so i'm sure i could make my own mind up when and when-not to use the tool!!

Steve said...

Thanks! Are you sure you are ready to leave home and make your own decisions? Revit has raised you right? Ready for the world? Sometimes a parent has to let go I suppose? I'd be pleased if they give me my wish and ready with the whip if someone misuses it! Cheers!


Anonymous said...


Great idea on the blank font.

I have found that if I just add a opaque text over the dim. text and send the file in dwf. format the opaqueness is lost and you see both. Not to mention exporting to AutoCAD...

A couple questions:
1. How do you make the blank font?

2. Any way to do this with levels?
ie. to replace the elevation with 'SEE STRUCTURAL'