A dxf file can contain only 1 shape (which can eventually have multiple holes).
A shape can be a polygon (with arcs as edges) or a circle. The polygon must be closed and non self-intersecting.
The following entities are read from DXF files: DL_ENTITY_POLYLINE, DL_ENTITY_LWPOLYLINE, DL_ENTITY_ARC, DL_ENTITY_CIRCLE, DL_ENTITY_VERTEX, DL_LAYER, DL_BLOCK, DL_ENTITY_INSERT. All other entities are ignored.
Entities can be located on multiple layers. It is possible (see menu Technical settings) to mix entities from multiple layers.