Generative Components confusion

Hello. 

I would like to use GC for my phd research but I am a little bit confused because the research papers or books where I`ve studied this software said that Generative Components is a standalone software and it`s free. 

When you enter on the website at Products - Brands you can't find Generative Components but you can hardly find it under the Products - Products and services - Modelling and Visualization menu that takes you here https://www.bentley.com/en/products/product-line/modeling-and-visualization-software/generativecomponents . On this link I can't find information about downloading the way i can find on other products pages.

On this link https://communities.bentley.com/products/products_generativecomponents/w/generative_components_community_wiki it says that it's an companion feature for OpenBuilding & other softwares and that Generative Component feature is free but you'll have to buy Open Building licence. 

Because I`m a new user I have to say that I`m very confused. I have few questions:

1. Is Generative Components still free and standalone?

2. On what products can it be installed as an companion feature?

3. Are there another products that have features of parametric modelling like generative components in bentley portfolio?

4. Is there is a document / link / book where I could study the evolution of GC, especially about this new rebranding movements? 

Thank you very much,

Cristian