If you want to trace from handdrawn image or have a 3d model you want to reference then you can import image in autocad as external reference.
Now the image is loaded in autocad you can unload,reload and detach image from external reference panel
Type 'image' or 'xref' in command line to open the external reference panel
From left side choose to add image
Browse the location for desired image
Choose to set insertion point and scale on screen . And set rotation as desired.
Now the image is loaded in autocad you can unload,reload and detach image from external reference panel
