Instance vs. Type Parameters

[PaperStreet SoapCO]

Hi everyone - I would just like to start off by saying thanks to everyone on this forum for all of the help they provide.

I posted some time ago about evaluating Revit for my firm ( we currently use ArchiCAD ) and now with a little down time I've got a month to do a side by side comparison (and now I've been alerted that I will be throwing Bentley Architecture into the mix). This is not a comparison to shout about which is best, but as a sort of state of the union address on the BIM world.

Ok, that being said, I have a question about a lot of the families in Revit. I notice that a particular object, say a door, will have all kinds of different sizes to choose from - but they are seperate objects so to say. Why would a person not want to set the sizes and other parameters of doors as instance parameters and not type parameters so that each door placed can be changed easily? I feel like a lot of families in Revit have type parameters that should really be instance parameters.

Perhaps I am missing a bigger concept coming from different software.

[architeach]

As someone who convinced and converted an entire office over to Revit from ADT I do not envy you at all. We have had amazing success with Revit, some people resisted but after a few months said they would never go back. Anyway, about your question:
I might be missing the point to your question, but it is easy to change each door within a project even if they are the same family. Our office will typically use the type parameters to for generic items such as size, thickness, frame size or type etc...We then use the instance parameters for more specific things like fire rating, hardware heading, finishes which will tend to change on a door to door basis. Does this help?

[PaperStreet SoapCO]

Yeah, I kind of realized the point of type and instance parameters after I thought about it for a while. I forget that despite all of the width and height options in the drop down menu they are still apart of the same family. I think its come down to an interface issue between programs but I definitley see the advantages now. That drop down menu does get a bit cluttered though....

Thanks for the help! I'm sure more questions will follow.

[architeach]

No problem...I agree that the drop down does get very cluttered. We have our templates set up to bring in the typical families and then we load new ones as the project gets further along. Once the project is really set with information and details we purge out all the unused stuff.
Cheers!

[aaronrumple]

Ok, that being said, I have a question about a lot of the families in Revit. I notice that a particular object, say a door, will have all kinds of different sizes to choose from - but they are seperate objects so to say. Why would a person not want to set the sizes and other parameters of doors as instance parameters and not type parameters so that each door placed can be changed easily? I feel like a lot of families in Revit have type parameters that should really be instance parameters.
Instance vs. Type is really more of an issue of how your office schedules objects and how you want to interface with the objects. My preference is to use instance parameters for height and width of doors. At the last office I was at, we had a door tag that displayed width, height, type and hardware group. Our schedule was set to do doors as type - not each individual door. It was a very short schdule. The instanced parameters could be changed directly in the door tag - and of course the size would parametrically change. The disadvantage is that you can't just redesign the type and have all the doors instantly jump to a new size.

The type parameter is a little simpler for the end user to pick off the list. And you can use the catalog feature to define large numbers of types very quickly.

[LRaiz]

The type parameter is a little simpler for the end user to pick off the list. And you can use the catalog feature to define large numbers of types very quickly.
Besides, family types (and type parameters) correspond to the real world notion of prefabricated objects that are purchased from a manufacturer's catalog. They are not build for a specific customer or installation while instance parameters better correspond to custom objects build for a particular (one of) installation.

[aaronrumple]

Besides, family types (and type parameters) correspond to the real world notion of prefabricated objects that are purchased from a manufacturer's catalog. They are not build for a specific customer or installation while instance parameters better correspond to custom objects build for a particular (one of) installation.
ah...but where Revit fails is in it's use of the Type Mark. If you have 20 door types in one family, they are really all the same type (as used in architecture), but the type mark isn't automatically filled out for each one. Also when you do put in the same type mark for each one - Revit warns you and to a new user this looks "wrong". What Revit really needs is the ability to add this sort of user defined information under Settings->Family Category and Parameters for a truly global "Type" designation.

This is one of the biggest reasons we went to instanced height/width - it resulted in far less QA/QC time rather than sifting through every door to make sure it had the right type designation on it.

[tim.101799]

Currently I am going through the process of making custom families for my office. Right now I see both sides to the instance / type parameter uses. It really depends on the family and how you/ your office wants to work.

For door families I am convinced that instance parameters are the way to go for our office. 99% of our work is commercial construction, and in those projects 99% of the single doors are 3'-0"W x 7'-0"H and 99% of the double doors are 6'-0"W x 7'-0"H. So I set up the door families with instance parameters set to the default of 3'-0" X 7'-0" (6'-0" X 7'-0" for double doors) and this covers most situation. On the rare occasion that a door is a different size the user can change the properties of that door.

EDIT: also, in our office (and most firms in my neck of the woods) we don't schedule doors by type. Every individual door get it's own line item in the schedule.

Tim

[Steve_Stafford]

It gets a little more confusing when, by "type", someone is really referring to a panel type, not a frame or overall door type. :smile: Best of luck!