GROUPS BEST PRACTICE

AN INSTANCE OF A GROUP CAN EXCLUDE OBJECTS, BUT NOT INCLUDE OBJECTS

If you have a situation where you have placed a group and it is slightly different, and you want to:

ADD OBJECT(S) - just place new objects over the top of the group. Even hosted elements like doors will go in properly.

EXCLUDE OBJECT(S) - select the object(s) to exclude (use Tab key), click on the group icon upper left of each object. A red line through the icon denotes it is excluded.

MOVE OBJECT(S) - First add object(s) as described above, then exclude the ones in the wrong place.

ALWAYS SET A SENSIBLE INSERTION POINT

By default the insertion point of a group is it geometric centre, which is rarely useful.

Whenever you create a group make sure you move the insertion point to a sensible location. Just highlight the insertion point icon and drag it.

AVOID CREATING GROUPS CONTAINING FAMILIES (COMPONENTS)

Create Furniture System families containing the families instead.

Families use substantially less memory than groups, and are more stable.

• • You can use Furniture System families for any category, not just furniture.

  • Reference planes can be copied (ctrl C) from your project to the new family to define the room boundary.

  • Dimensional parameters can be set up that move components within the family reducing the number of unique families (and groups).

  • BUT make sure families inside the Furniture System family have their Shared parameter ticked. If they do not they won't schedule or tag.

DON'T PUT LEVELS AND GRIDS IN GROUPS

Avoid putting datum (levels and grids) objects inside your group. First, you can’t manage the extents of the datum unless you’re in Group Edit mode, which can create conflicts elsewhere in your project. Of course you will have the option to not include the datum when you bind your link. Again, this doesn’t necessarily create a technical hurdle. But it can create a lot of confusion. Risks include duplicate levels being deleted, only to find out that those levels were hosting content in the project.

DON'T USE ATTACHED CONSTRAINTS IN A GROUP

Best example is:

You cannot have walls with level-attached tops inside a group if any floors you wish to place those groups on another level that has a different floor to floor height.

You may observe the behavior for walls inside groups is benign. As you may know, elements such as a wall can be given either an explicit height, or have its upper extent constrained to a level, floor or roof element, or a reference plane.

Since nested elements must remain consistent in every instance of a group, those which contain walls that are top-constrained to a level, attempt to respect the resultant height of the constraint to the next adjacent level. At least the walls do not break the group if placed on levels whose floor-to-floor height varies.

An override for Top extension is auto-magically placed on the new nested wall instances to keep them consistent, and no warnings are displayed. You have to be mindful of what really happened. A properties override, if you will, was assigned to the new walls during their creation. Looking at the walls from an section or elevation may not show any difference.

If you attempt to change the height of your levels, you will be in a severe amount of pain.

The feared warning will come up stating: “Group instances of the same type do not contain identical members.”

When you are presented with the option to Fix Groups… Revit simply asks you to ungroup or make unique groups for the naughty thing we just did.

RECOMMENDATION:

Don't use a group over more than 1 level if it contains walls, floors or ceilings. Make a group per level.

DON'T INCLUDE HOSTED FAMILIES UNLESS YOU ALSO INCLUDE THE HOST

Doors, windows and components that are wall or ceiling hosted should NOT be included in a group if their host is also not in the group.

In theory it should work, and sometimes it does, but other times it will kill the group. Best to avoid.

DESIGN OPTIONS

Don't mix objects from different design options in a group.

NESTING GROUPS

Groups can be nested inside other groups, but to avoid possible problems:

• • Only nest 1 deep

  • If you create a group containing other groups ONLY include groups. Don't include elements that are not in another group.

  • Make sure nested groups all have their XY axis pointing in the same direction.