cad图层无法分解怎么回事，而且一选是一大片，怎么分解？

多重插入或多重引用，加载个lisp文件试试，网上有
把以下内容保存为lsp文件（如exm.lsp）,加载后运行exm既可把“多重插入块”转换为“普通块”，然后既可用“explode”分解。加载后运行lockb可把“普通块”转换为“多重插入块”
;;-------------------------------------------------------------
;;转换“多重插入块”为“普通块”。
(DEFUN C:exm ()
(setvar "cmdecho" 0)
(SETQ STM (car (ENTSEL "\n点取多重块")))
(while stm
(setq e (entget stm))
(setq stlx (cdr (assoc 0 e)))
(if (= stlx "INSERT")
(PROGN
(setq r_zm70 (assoc 70 e))
(setq c_zm71 (assoc 71 e))
(setq r_dist_zm44 (assoc 44 e))
(setq c_dist_zm45 (assoc 45 e))
(setq e (subst (cons 44 0) r_dist_zm44 e))
(setq e (subst (cons 45 0) c_dist_zm45 e))
(setq e (subst (cons 70 0) r_zm70 e))
(setq e (subst (cons 71 0) c_zm71 e))
(setq e (subst (list 100"AcDbBlockReference") (list 100"AcDbMInsertBlock") e))
(entmake e)
(entdel stm)
))
(SETQ STM (car (ENTSEL "\n点取下一多重块")))
)
(setvar "cmdecho" 1)
)
;;--------------------------------------------------------------------
;;转换“普通块”为“多重插入块”
(DEFUN C:lockb ()
(setvar "cmdecho" 0)
(SETQ STM (car (ENTSEL "\n点取块")))
(while stm
(setq e (entget stm))
(setq stlx (cdr (assoc 0 e)))
(if (= stlx "INSERT")
(PROGN
(setq r_zm70 (assoc 70 e))
(setq c_zm71 (assoc 71 e))
(setq e (subst (cons 70 1) r_zm70 e))
(setq e (subst (cons 71 1) c_zm71 e))
(setq e (subst (list 100"AcDbMInsertBlock") (list 100"AcDbBlockReference") e))
(entmake e)
(entdel stm)
))
(SETQ STM (car (ENTSEL "\n点取下一块")))
)
(setvar "cmdecho" 1)
)
;;--------------------------------------------------------------------

(defun c:unlk (/ en ent)
(setq en (entsel "\n请选择被加密的图形:"))
(if en
(if (= (cdr (assoc 0 (setq ent (cdr (entget (setq en (car en)))))))
"INSERT"
)
(progn
(setq ent (entmakex
(list '(0 . "INSERT")
(assoc 2 ent)
(assoc 10 ent)
)
)
)
(command "_.explode" (entlast))
(entdel en)
)
)
)
(princ "\nOK，解密成功。")
(princ)
)

图层？一选一大片应该指的是图形吧，如果你的图是别人拷给你的并且无法炸开的话那应该是图形被加密了，能看，能打印但不能编辑。要解决这个问题你需要找拷给你图的人，看能不能解密。现在很多CAD加密软件的加密过程是不可逆转的，也就是说能修改的可能不大。