Forums >> Revit Building >> Technical Support >> can't make change to group with more than one instance

sadpanda

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Revit 2011, here's the error message:

can't make change to group with more than one instance. To resolve: ungroup and group again under a new name. Edit and make change, then change all instances of the original group to the new group.

what the heck?

doesn't this defeat the entire purpose of grouping if you can't edit the group and have it update all instances??? this seems like a massive shortcoming in Revit, i'm surprised i haven't seen more threads on this. what good are groups if you are limited to only one instance???

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WWHub

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Something is wrong at one of your group locations and Revit can't change it.  This error occurs occassionaly depending on what you have done but it is not typical.  Depending on how many locations you have, the problem might be hard to track down. 

Do you have some groups in design options?

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sadpanda

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WWHub-

not sure what you mean by "groups in design options"

i only have 2 instances of the group so far, it is a building core made up of a few walls and doors, nothing special. I deleted one instance, ungrouped the other, regrouped and tried to copy to aligned level, but now i keep getting the following error message:

group instances of the same type do not contain identical members. Press "fix groups..." to select from options to make the groups consistent. corresponding group members in different group instances diverge in the following respects: different types

how can this be if i am starting with a single group instance? this is very scary.

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WWHub

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Be very careful when you group objects.  Make sure that you have objects that can exist in a new location.  That means if you have a door in the group but not the wall, there will be a wall in the same relative location so the door can be hosted.   So your problem is that something can not exist in the location designated.

You might look at your copy / paste process.

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sadpanda

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WWHub, thanks for the help, i think i solved this.

i ungrouped my group, selected a couple walls, grouped, copied group to aligned levels, then began adding elements to the group one wall / door at a time (saving after each addition / updating other group instances), until i eventually found what was causing the error (in this case, it was an interior wall meeting an exterior wall / i disallowed the wall join and this solved the issue).

it took forever to isolate the problem, i wish Revit would just come out and tell you what the problem is (since it knows) instead of the user having to go through all this.

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WWHub

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That was not your problem.  Grouped walls will join with both interior and exterior walls that are not in the group.  Had to be something else but glad you got it working.

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mikeinsverige

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Joined: Wed, Jun 15, 2011
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I am getting this same error message when trying to edit a group. I selected a bunch of things, cut, and pasted them in the group (quicker than doing Add one by one). Now I cannot finish and save the group because of the error. But, I only have one instance of the group! It is possible that I got a door in there without its wall, I will see...

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WWHub

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You should know more about what you included than we will.  You should learn to always use your selection filter.  Especially if you used a crossing selection.

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mikeinsverige

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Yes, I like the selection filter, but I wish it could be more precise. I was trying to only get certain types of doors and walls, but the filter only shows "walls". I basically had to pick and choose manually, except for a few cases I could use "select all instances".

I was able to cancel and do it again in more steps to see where the problem was, but didn't find the problem after all - it seems ok now. The project is getting big so I was making a group of all the facade elements, to convert it into a linked file.

Then, when I tried to make a link, it said "elements will be deleted". Most were dimensions which I don't mind, but it also included two walls. I did "select by ID" and it said no good view could be found. It did select the wall(s) though. In the properties it did not list any level, and I could not find it. Reminds me of a wall by face. But the wall type I know was not used by face, but drawn regularly, as a curtain wall base. I just have to hope the two little deleted walls will not cause big problems...

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WWHub

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First, this is the wrong use of groups. Groups are meant to be used for multiple placement of same elements, not just to "group" items together.  Be careful with groups because when used incorrectly, they can really slow down a model.

Second, What do you mean this file is getting too large?  How big is it and what is your system?  We consistently have files up to and over 200 meg on 32 bit systems.

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mikeinsverige

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When I was grouping the facade walls and facade groups together, it was to make one single fasade group into a link, so the content would then be in a different rvt file.

It seems that compared to your example, our file is not so big, it is only 100 MB. But, it is rather slow - it can take 10 seconds to open a view, move a section, or print a sheet. The facade consisted of many groups (e.g. group for north facade levels 4-18, west facade levels 21-24, etc.) so I thought it could speed things up to save the facade out as a separate link.

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WWHub

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Your slow problem could be many issues.  Groups do cause some slowdown issues as I stated and your use of groups I believe is un-necessary.

Here are some things you can do to improve your model performance.

1. Audit & compress your central file on a regular basis. (Regular? - If file increased > 10-15 meg might be a good rule)
2. Review warnings and fix as many as you can... maybe every-other audit
3. Limit the use of locks
4. Limit the use of groups
5. Close un-used windows
6. Restict the use of tiled views
7. Don't use overly complex or over modeled families
8. Don't over-load your template - keep it simple as possible
9. Purge un-used families (be careful here)
10. USE WORKSETS!!!! -
11. Use VG and worksets to control and limit view contents.  (Don't have interior furniture on in an exterior elevation view.)
12. Pay attention to view depth for sections and elevations.  (Pull the view depth back in plan so Revit doesn't have to hide elements behind the planes you are elevating.)
13. Limit the use of imported CAD and always - ALWAYS clean up CAD in a junk Revit project before copying into your project.

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mikeinsverige

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Thanks. I think we are already doing most of those things. I can see you are right in that they are good practices.

The things lacking would be that I have not had time to go through the warnings very often. Maybe I could do that today. And, we have lots of groups. I do not think that walls can be part of a family? So where we have some repeating room layouts we have often used groups.

It is nice that the file is a lot faster now after making the facade link!

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JB27

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I realize this thread is quite old, but I just came across this error message for the first time.  I also had only one instance of the group, so I don't get why it's telling me it can't make changes to more than one instance.  Even when I deleted ALL of the objects in the group--leaving it completely empty--this message still came up.  Any idea what causes this?  Unlike most error messages, when I expanded, it did not provide any identifying families or part numbers.

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mikeinsverige

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Hi JB27, fortunately this doesn't happen often to me but when it does happen I haven't had a great fix. What I usually do is what "sadpanda" posted: "To resolve: ungroup and group again under a new name. Edit and make change, then change all instances of the original group to the new group."

If you only have one instance of the group it should be quite easy.

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