English expressions for objects in 3D perspectives

[Floezen]

Hi,

I am looking for some English terms regarding architectural visualizations.

1.) Is there a word for all those objects which are often only added in Photoshop to a rendering, like humans and trees?
2.) What is the most appropriate English term for Photoshop objects, that are freed of there surrounding (like on a own layer or with an alpha mask)?

Thanks!
Flözen

[Floezen]

No one with a suggestion?