topic Re: Find GenericForm generating solid of family instance in Revit API Forum

Find GenericForm generating solid of family instance

nachaur — Sun, 03 Mar 2024 20:49:07 GMT

Hi!

I’m struggling with families and its geometry. Maybe someone can help me to answer my question.

I have a family instance. By analysing its geometry I know that it consists of 6 solids. If I open the family though CurrentDoc.EditFamily(familyInstance.Symbol.Family) itself I find out though filteredElementCollector that in Family Document there are 6 GenericForm objects that generate those solids of FamilyInstance. Is there any way to know which GenericForm of family document is associated with which solid of family instance geometry?

Best,

Nastya

Re: Find GenericForm generating solid of family instance

jeremy_tammik — Mon, 04 Mar 2024 09:38:03 GMT

You can obviously perform a geometrical analysis comparing shape, size, location and orientation of the objects in the family definition and the family instance. I am not aware of any other standard identifiers that you could use. You could obviously add some features yourself to help identify what is what. In HVAC equipment, for instance, you often equip the surfaces with connectors. These could be used to identify the corresponding surfaces in the family instance. For generic forms, you could add little line segments of different lengths to various faces, for instance, using the line lengths to identify and differentiate them. Maybe you could even add lines and hide them, so they do not disturb visually. This is just crazy brainstorming, of course.

Re: Find GenericForm generating solid of family instance

nachaur — Mon, 04 Mar 2024 15:04:06 GMT

Hi, Jeremy!

Thank you for your fast reply.

I started to perform geometrical analysis. However, I faced one issue.

The geometry of generic form and family instance might be different due to parameter values.
For instance, I have a family instance that looks like this:

And when I open a family the geometry looks next way. It is different because of the different parameter values assigned to the family.

So, in this case, I can not compare the geometries of GenericForm objects and family instance solids because of their different sizes.

What I tried to do is to temporarily change all the parameter values inside the family editor so the family geometry matches the family instance geometry and perform geometric analysis. However, this approach doesn't find all generic forms associated with solids. Also, the performance of this approach is very slow.
7.65 seconds just to analyze a simple family.

I attach the code below, hopefully, it helps the issue to be found.

Best,
Nastya

Re: Find GenericForm generating solid of family instance

jeremy_tammik — Mon, 04 Mar 2024 15:08:10 GMT

Yes, that all makes sense.

> I attach the code below, hopefully, it helps the issue to be found.

What issue? Afaict, everything is working as designed. I made one suggestion for a possible approach to speed things up above by adding some marker elements. Maybe you can invent a better way. I wish you the best of luck doing so and implementing an optimal approach that fulfils all your requirements.