串联门洞的前后遮挡

提示词

按已给通道和各道开口的位置，把近处洞口、后续门框及末端可见空间分成前后层次；每个框保留所属墙面与洞口边界，后方只从前方实际开口范围中显露。

Use the supplied passage and doorway positions to distinguish near openings, subsequent frames and the visible space beyond. Keep each frame on its own wall plane, revealing rear elements only through the actual apertures in front of them.