Objective: Create a 2D Sprite of a 3D object using the free Screenshot Utility asset from the Unity Asset Store.
Step 1: Add the Screenshot Utility asset from the Unity Asset Store and install the asset by opening the Package Manager window from the Window menu, select My Assets from the Package dropdown, find the Screenshot Utility asset in the list, select it, and click Import.
When the Import Unity Package window pops up, click the Import button.
Step 2: In Unity, set the Scene view to 2D mode and drag the 3D object from the Project window into the Hierarchy window.
Step 3: Select the 3D object, and if needed, in the Inspector window, adjust the Position, Rotation, and Scale of the 3D GameObject, but be sure the 3D GameObject fits within the Main Camera’s viewport.
Step 4: Select the Main Camera in the Hierarchy window, and in the Camera component in the Inspector window, change the Clear Flags option to Depth Only and the Projection option to Orthographic.
Step 5: From the Tools menu, select Screenshot. In the Screenshot window, select the Game view as the Source, select the desired image resolution and output location, select PNG as the file type, and click the Capture button.
Step 6: Drag the exported PNG into the Sprites folder in the Project window.
Step 7: Select the PNG image, and in the Inspector window, select the Sprite (2S and UI) option as the Texture Type, be sure that Alpha Is Transparency is checked, and click the Apply button.
Now the 3D Object has been rendered into a PNG image, then converted to a 2D Sprite with a transparent background, and can be utilized within the game.