How to change shape of earth under the ground floor?

[Anonymous]

Hi guys, 

On screen (red) you can see the earth symbol. Is there any way to change shape of it like I show on pic?

Thanks,

Chris

[constantin.stroescu · Accepted solution]

Create a Masking Region with Invisible Lines as borders:

• Annotate > Region >Masking Region - draw a closed contur
• select the Masking Region > Mode > Edit Boundary > select Lines of the border > Line Style - < Invisible Lines >  and OK