Chief Architect is architectural and interior design CAD software.
Open a 3D model in Chief Architect
Select File → Export → Export 3D Model (3DS)
Uncheck Truncate Texture Names and select Export
Create a new folder with the name of your project.
Open the folder, name the project and save the model. (You're also saving the materials)
Navigate to the new folder and compress it into a .zip file. (This is important if you want the materials to show in your online models)