Currently, the only way to get a design to the 3D editor from Codeblocks is to make it a Part. You won't be able to take it apart like a grouped 3d design, but you can drag and use it as a design component in any 3D design.
To make a Part and share it to the 3d editor-
- Open the Design you want to send
- Click the Export button. When the Export menu opens, Select the 'Part' button to open the Part viewer.
- Fill in the Name of your Part (this is required) and add any information you might like to add like description or tags.
- Click 'Save Part' and the viewer will close.
5. Now, go to the 3d editor. Click the Tinkercad logo, select 3D Design button in the User dashboard and either open or create a new 3d Design.
6. When you 3D Design is open, Click the 'Basic Shapes' button in the Shape Panel. This will show a menu of Shape Collections. Scroll down to and select the 'Part Collection'.
7. You will see your new Part appear in the 'Part Collection'.
8. When the Part is loaded, drag it to the Workplane. Since it is a new creation, it may take a second or two load the model into the workspace.