In 2011 with the introduction of the properties palette we implemented more pre-setting of properties on placement. Internal these are called "Dummy" elements since they are not real until an instance is placed. They are stand-ins like crash test dummies.
Take the case where you are drawing a duct. The reason that you can set the size and elevation of the duct is because a temporary duct is “created” (maybe not placed, but created) and you are actually setting the size and elevation of that temporary duct. When you go to place another element those “last used” properties are remembered from that temporary element and those becomes the defaults for the “next” element to be placed. The same is true of wall base offset.
Prior to the 2011 release, for most “loadable” categories (the categories which support loading an .rfa file as the thing being placed, which is different from things like duct, pipe, and wire) MEP didn’t implement these “temporary” elements. As an example of this if you start 2010 and start to place an electrical device and go to instance properties, you’ll notice that the dialog is completely empty (no properties, nothing, type properties are there, but nothing for the instance).
As implementation of the properties palette began; people noticed that for a number of categories the palette was empty, which completely negated its usefulness when placing certain dummy-less elements. The solution was perceived to be quite simple, since we already had it for other elements. Unfortunately in the case of face based families, there is both a type parameter (Default Elevation) and an instance parameter (Elevation). From above, the rule is for placement to remember the last used value, so if Elevation was previously set to 18” it’s going to be set to 18” next time as well (regardless of what the Default Elevation parameter says).
There were additional issues that have been identified but are really the same problem. There are a number of people who, for different family types supplied different instance parameter values. For example on a Lighting fixture I have a parameter called "Load" and it is an instance parameter. I have two types for this family, a 2x4 type and a 2x2 type. In family editor, for the 2x4 I set the Load value to 96, and for the 2x2 I set the load value to 50. This worked fine in 2010 and previous releases, but because of the new rule about remembering instance parameters, when I change types the load value will NOT change, as it is now remembered. There affected all the verticals but might have been most visible in MEP since it used this “lack of functionality” more than others generally did. This is a case where we gave MEP users the ability to specify instance parameters before placing the instance, which they’d never had before, and of course might have loved, but it turns out to be otherwise. There is a phrase about how roads in the nether regions are paved with good intentions.
For the web update 2 we enabled an ini setting to adjust this behavior.
To do this:
Browse to wherever you have Revit installed and open Revit.ini with your favorite text editor. Search the file for the term "UserInterface". If a string of "UserInterface" is found it should be in brackets, and if it is, somewhere below that (but before another bracketed term) enter the string"ResetInstParamsPerTypeFor2011DummyInst = 1"(sans quotes) on a blank line
If the term "UserInterface" is not found then at the end of the file paste in the following:
[UserInterface]ResetInstParamsPerTypeFor2011DummyInst = 1
I’d like everyone who can to set this and continue testing as normal to see if there are any issues. It mainly affects certain types of loadable families. The ini setting will be valid for all alpha releases as well if you are participating there.
So far the setting appears to address the issue for those who were affected by the 2011 change. To make the fix permanent we want to ensure it does not adversely affect people who were not seeing the issue and so we would like more people to enable it.