How to create family from solids?

[KM_Yotsuha]

I have some solid achieved from project file. How can I save the solid to a family file?   

I  have read an article, it says you can output GeometryObject to a family file, I can't find that article now.

[jeremy_tammik · Accepted solution]

The family definition is stored in a Revit RFA document. Just like the Revit project RVT document, everything stored in the document database must be derived from the Element base class. GeometryObject is not derived from Element. It is a memory-only object and not stored in the database. So, you cannot create a family definition just from pure geometry objects. One way to represent geometry in both RVT and RFA format is the DirectShape element: 

https://thebuildingcoder.typepad.com/blog/about-the-author.html#5.50

[KM_Yotsuha]

thank you. Is there any way to save solid as a SAT file? so that I can use  "familydoc.lmport" method to build a family file.

[jeremy_tammik]

A SAT file is a Standard ACIS Text file:

https://en.wikipedia.org/wiki/ACIS#File_format

> SAT files are ASCII text files that may be viewed with a simple text editor. A SAT file contains carriage returns, white space and other formatting that makes it readable to the human eye. A SAT file has a .sat file extension.

https://en.wikipedia.org/wiki/ACIS#Structure_of_the_Save_File

> Specification of SAT format for version 7.0 (circa 2001) has been made publicly available. 

So, you can write the SAT file yourself.

Where does the solid geometry that you wish to save and import come from?

Is it just in your head, or do you have some hard data to use to generate it?

Here are some more details and an example:

http://paulbourke.net/dataformats/sat/sat.pdf

If you don't want to generate the SAT directly yourself, you can generate direct shape in Revit and save that as a SAT: 

https://thebuildingcoder.typepad.com/blog/2012/01/export-walls-and-floors-to-sat.html