search for ideas, code snippets to unify layer_a and layer_b in SW-drawing on layer_ab in dxf
One of the possible approaches you can take is:
Another approach is to layer-by-layer hide all layers except of the ones required to be merged (i.e. a and b) using ILayer::Visible property. So only those entities are visible. Then select all entities (you can use IModelDocExtension::SelectAll method). Now use the following example: Change Layer For Selected Objects In Drawing to change the layer for all selected entities to the merged one (ab). Now save dxf and undo changes.
thanks for your ideas. Think will try the second one
Retrieving data ...