Tuesday, March 24, 2009

Scheduling the Unschedulable

The more we venture into BIM (taking real advantage of our Revit models), the more this subject is starting to tick me off. You’ve been warned!

Let’s take a look at what caused this “rant”.


Here you can see the family parameter “Structural Material Type”. I want to use this really bad because I’m doing quantity take-off schedules for all elements, which include structural framing elements residing in a linked file. So I want to create a framing schedule for steel and another for concrete. The reason is that I want to find the total weight of each material in the job and as you know, concrete and steel have different densities.

So to calculate this, one can create a calculated parameter in the schedule and voila. I would prefer to expose the density used in the schedule (so everyone can see it. I don’t like to bury assumed values in formulas if possible). However since the families reside in a linked file, you cannot add this information to your project via a project parameter, so you can only have one formula with a fixed value (one density value). So the only way to do this is to create schedules for framing members with different densities. I know, I can get into the linked file, but that’s beside the point.

Unfortunately, you cannot schedule the above highlighted parameter, which would typically raise the question, then why the %^&**&?!!@? do we have it? How can I filter views/schedules of my insanely intelligent model? I cannot even filter by family name or type either!

This is only one little thing I came across and is very irritating. I found more issues when calculating volumes, but that will be another very lengthy post, so stay tuned.



Gonçalo Craveiro Feio said...

I Dave
I too have been struggling with that issue.
I do my quantities in an outside to revit database, and the takeoff must be in volume for concrete and weight for steel. For that, I have to use tweaks in the database queries, in the material quantities table (crossed with the assembly code and keynote).
I would really love to see that structural material exported in odbc!

Erik said...

I feel your pain. The day before yesterday I was pulling my hair out over what seemed pretty simple. Total the Number of Studs in a project. Easy enough, right? Structural Beams have a parameter (hard coded and not accesable till family is in the project) for Number of Studs. All I SHOULD have to do is set that column in the Schedule to "Calculate Totals." The rub is that parameter is of the type; "Text."

GRRRRRRRR, why would you EVER make a parameter that MIGHT be used in calculations a TEXT parameter. The name "Number of Studs" should have cleared up for the programer what type of parameter it should be.

I know, I know, Number of Studs is usually enclosed in Parenthesis on plans and they wanted it to appear that way in Revit to (I think that's why they did this) but I can add those in the Prefix and Suffix columns on my beam tag.

BTW, WARNING: Rant proceeding!

David Light said...

Good one....you also need to watch it when calculating weights of steel (if you managed to do it) as Revit SEEMS to have an issue between levels of detail. What you actually want is the fine level of detail to be calculated, but I discovered last year it seems to pickup the medium level, which screws with the results.

Jason Grant said...

I hear you David... too many bad things in families that prevent you from using them to their full potential.

Autodesk really needs to take a step back and make sure the entire program works efficiently and correctly before they waste time on things like UI or any new tool. How can a new tool benefit you when you cannot even use the program 100%.

Dave Baldacchino said...

Thanks for your comments guys! Hopefully someone at Autodesk will finally start seeing what issues we run into exactly, regardless of whether we are part of the test group or not. There are no excuses now. Thank you Web 2.0!!

David, that's what I was hinting at regarding volumes. I will be posting at some length on that. I took some time to figure out what Revit's logic is and I think I have it down. My opinion? It's INSANE!

I just don't understand why not all family parameters are schedulable. Maybe this was part of the "dead" elevation tag guy's work?

Next I'll post what I did to work around the issues and how I finally did manage to get my weights. I'll hopefully get some testing time on other external applications too.

Dan said...

Are you gonna mention the innacuracy of the Volume while we're at it? :-)

Dave Baldacchino said...

Patience ;) You won't regret the analysis!

Priit said...

I sometimes think who designs the software and for whom. If I need to make new parameters and etc for getting the weight , it is not normal. Why have materials , why then it just does not read the weight from that material and multiply it by volume. Usually what irritates me mostly, is that i have everything modelled and now i try to make a schedule quickly but then i find out that its not so quick...

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