Groups - to have or have not

[david_peterson]

So I've taken a look around and haven't seen anything to the contrary, but I have a co-worker who seems to think that groups are evil and cause performance issues in models.
I'm not sure, so I thought I'd pose the question.
Are detail and/or modeled groups a good idea or a bad idea?
I've used them a lot and haven't really run into many issues with them, so I'm saying groups are a good thing.
Thoughts?
Thanks in advance.

[Maciej Wypych]

Hi,

I find groups quite useful, but it's easily to get into a problems if you have any face/wall/floor based families. If you avoid using these, groups work fine.

[damon.sidel]

Like maciejw, I've run into problems with objects in groups that are hosted to objects outside of groups. This usually just results in warnings and those objects not showing up in a particular instance where it can't find a suitable host.

I've also had problems with walls in a group that want to join with walls outside the group, especially if the walls have profiles drawn. This has caused some pretty significant "object corruption" errors and people lost work. We now disable wall joining on any wall inside a group.

We've seen two performance issues, both avoidable. First, nested groups. I've been on projects where we made interior unit layout types as groups. Then somebody insisted on grouping all the units together into a mega group and mirrored the whole thing (symmetrical building). It really seemed to bog the project down. Second, on a huge (~10M sf) project we had a rookie Revit user creating detail groups and copying them all over--instead of creating a detail family. That file had serious performance issues, so we tested a few things. When we deleted all the detail groups, it was significantly better size and performance. (That tweak came in second to deleting the MANY area plans... that was the biggest performance issue.)

All that said, we use model groups extensively. We use them a lot on high-rise projects for unit layouts, window-wall configurations like bay windows, and area plans--we make a group of the area boundaries and areas then copy them to multiple similar floors. Sometimes we use them for repetitive balcony assemblies.

[KoryCox]

I'm in the against camp.

I've had problems and lost work with colleagues using groups for layouts, then they get mirrored around and used on multiple levels-then they break and we lose model elements. Mostly having to do with walls and hosted elements.

I've been able to warn the rookies away from using detail groups as detail components and that idea seems to have taken hold so only minor problems there.

I find links to function much better for interior layouts and similar.

[cdatechguy]

If used properly groups are great. For example I use curtain walls for my windows. I can create one, group it, place the grouped CW where I want it....then if make modifications or add more detail I only to modify one instead of multiple.

But I have seen groups used for the wrong reasons...such as someone creating linework and grouping it so they could copy it to other places...instead of taking the time to create a family with symbolic lines.

[cgallatin538076]

I agree that if used properly, they are tremendously helpful. But yes, the user must be well educated in groups and how they work.

We use them the same way cdatechguy does with CW groups and its a major time saver when you have 40+ openings all the same and you want to make an adjustment to say your sill ledger profile. We also use them for our plan details and section details that have similar conditions. But again, the user MUST be well versed in how your firm is using groups because groups mistakes have domino consequences.

Here is a good write-up on detailing with groups http://www.revitstore.com/index.php?option=com_content&view=article&id=152:ultimate-detailingcoordination&catid=37:tips-and-tricks&Itemid=55

cheers!