Using a geometry viewer in a revit addin to preview results

[jesse.mom]

Hi all,

I'm trying to build a revit addin that will generate geometry in revit. In my addin, I would like to integrate an interactive 3D viewer that shows a preview of the geometry that will be generated. Basically, i'm looking for functionality such as the revit extensions offered by Autodesk, specifcally the "Wood Framing Walls" extension. In this extension, you can configure something, and see a preview of what will be generated in revit. (see attached image).

My question: does anyone have suggestions for open source or free 3D geometry viewers that can be included in a revit addin to preview geometry that has not yet been created in revit? Specifcally, does anyone know whether the viewer used for the revit extensions has some kind of API or is publically available somewhere( since I like the look and feel of it)?  Or is this something Autodesk can make available? The geometry to preview are simple beam shaped elements and lines, just like the example in the picture. 

I've found the articles by Jeremy on his building coder blog

[CaoduroC]

A little bit later on this conversation but I would like to understand how can be possible to introduce the Revit viewer in a modeless application. Using Helix is fine but I have seen tools like Sofistik Bridge using an interactive Revit view within the form. 
Is there any documentation around this?

[folkert.van.leeuwen]

Hi, 

I took a quick look at the Sofistik Bridge tool for Revit.

What i can see is that they don't use Helix as we did in this topic. They use the PreviewControl class.

You can only show existing Views and control the navigations in the winform and very easy to set up!

Revit API:

https://www.revitapidocs.com/2015/50112279-5c9d-0351-bbd1-698e76be9e36.htm 

Examples:

https://spiderinnet.typepad.com/blog/2014/12/revit-net-api-create-custom-preview-control-previewcont... 

Good luck!

[jeremy_tammik]

The Building Coder has a whole topic group with information on the PreviewControl:

https://thebuildingcoder.typepad.com/blog/about-the-author.html#5.7