Are model groups useless in Revit?

[gnarkill283]

Every time I make model groups, I get all kinds of errors when I try to make an update to them. How else are we supposed to propagate changes throughout a project without tediously changing each identical instance? All I did in this model group of 4 roofs, is extend its boundaries but alas I get these messages below. It also take 10-20 min for revit to make the change or mirror the model group of very simple elements - could it be because of associations with grids or other elements? If so how do I remove these associations? Anyway in general, this aspect of the program needs serious attention...

[barthbradley]

Are model groups useless?  For the inexperienced they are. 

Looks like you may be be editing groups incorrectly. Are you ADDING existing elements from the Model to the Group?   

[hmunsell]

you gotta be mindful of what your grouping.... i can see where grouping a System Family, like a Roof, could produce these kind of errors. System Families often have other things there reliant on that could restrict its updateing. 

[barthbradley]

What may be going on is that you are introducing new elements to the Model while inside Group Edit Mode.  New elements include modifications to assemblies - which I think @hmunsell is alluding to.   Changes, modifications, new assemblies, etc. need to exist in the Project BEFORE entering Group Edit Mode.  You ADD "stuff" to the Group in Group Edit Mode. You don't create or introduce new "stuff" to the Project while inside Group Edit Mode.  

[gnarkill283]

I'm not adding anything. I made 4 roofs then combined them in a model group and copied that group 20 times. Now I have to edit the extents of those roofs so I go into the model group and edit the boundaries of the roofs which causes all kinds of errors

[hmunsell]

your putting 4 roofs into 1 model group? Why are you grouping them, Are you using them in other locations? 

[gnarkill283]

I copy them 20+ times. Here is another error I get:

[ToanDN]

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@gnarkill283 wrote:

I copy them 20+ times. Here is another error I get:

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Are you rotating copies of the group?

[hmunsell]

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@gnarkill283 wrote:

I copy them 20+ times.

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sorry... missed that part in your pervious comment :-). 

[barthbradley]

So, all you are doing is editing the sketch boundary of a roof?  Sloped Glazing?  

[gnarkill283]

This first errors I mentioned are probably caused by having design options which I have 3 of for these roofs. The model group is the same throughout those design options so when I change a group in one option it has to create new groups in the other design options.

[barthbradley]

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@gnarkill283 wrote:

This first errors I mentioned are probably caused by having design options which I have 3 of for these roofs. The model group is the same throughout those design options so when I change a group in one option it has to create new groups in the other design options.

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I can't connect those dots. Are you by chance nesting groups?  

[stefan_gokstorp]

if you are using the group in several diffrent design option all at once (which i didnt know was was possible) that  why its slow. working with one design option slows the model down. if what you descriping is true, you are essential making changes through the group in several at once. im amazed it doesnt crash to be honest.