The first step to creating your 3D PDF is to select the file that needs to be converted. You can either reload a saved session file or start with a new file. To do this:
Each file type is converted by an interface. Some interfaces convert more than one file type. Some file types are converted by more than one interface. To allow user selection to resolve these multiple interface cases, the option box can be ticked for each file and the preferred interface specified in the drop down list (in above case "Coin Interface").
If options are not enabled, and a multiple selection is available, a dialog box is presented for each file. Here the list of available interfaces is presented and can be selected interactively. To avoid long and tedious selection menus, the apply to all similar box can be ticked to avoid further requests.