topic Re: Difference between FamilySymbol and ElementType? in Revit API Forum

Difference between FamilySymbol and ElementType?

Anonymous — Wed, 12 Dec 2018 05:41:42 GMT

Both FamilySymbol and ElementType seem to represent the same idea. What is the difference between the two? (I know one derives from the other)

A related question is: what's the difference between Element and FamilyInstance? I can't understand why stairs are of class Stairs (derived from Element), while doors are of class FamilyInstance. Are stairs not an "instance" of a particular "family"?

Re: Difference between FamilySymbol and ElementType?

jeremytammik — Wed, 12 Dec 2018 07:52:55 GMT

Families come in several flavours.

The two main ones are standard and built-in.

Standard are defined in RFA family definitions.

Built-in are built into Revit directly.

Standard families define family symbols, and when you place a family symbol, it is represented by a family instance.

Other elements placed in the model are not called family instances; they are just elements.

Element is a super-class of FamilyInstance.

Analogously, ElementType is a superclass of FamilySymbol.

I hope this explains.

For more info, check the developer guide:

http://help.autodesk.com/view/RVT/2019/ENU/?guid=Revit_API_Revit_API_Developers_Guide_Introduction_Elements_Essentials_Other_Classifications_html

Revit Developer's Guide

Revit API Developers Guide
- Introduction

Cheers,

Jeremy

Re: Difference between FamilySymbol and ElementType?

Anonymous — Thu, 13 Dec 2018 02:30:32 GMT

Ah, that's very helpful, thank you for the explanation and links!

Re: Difference between FamilySymbol and ElementType?

jeremytammik — Thu, 13 Dec 2018 12:18:10 GMT

Thank you for your appreciation!

Shared for posterity by The Building Coder:

https://thebuildingcoder.typepad.com/blog/2018/12/dynamo-symbol-vs-type-and-exporter-exception.html#4

Cheers,

Jeremy

Re: Difference between FamilySymbol and ElementType?

hrasmussen — Fri, 05 Mar 2021 20:13:40 GMT

Jeremy,
If I had to guess, I'd say you've been the guy with the answer to about 80% of my Revit API questions - thanks for all your posts (this one included)!