;;In lambda-3d.asd
(setf (logical-pathname-translations "lambda-3d") 
      `(("**;*.*.*" ,(concatenate 'string
                       (namestring (make-pathname :directory(pathname-directory *load-pathname*)))
                       "**/*"))))
If I have a file called cube.dae in the same directory as lambda-3d.asd I can refer to it as #p"lambda-3d:cube.dae".
Document written by Thomas Atkins