Convert AutoCAD Civil3D (dxf) to Esri ASCII Grid (asc)

Hi, I just want to convert a 3D-dxf file to a asc Ersi grid file. What transformer could I use to accomplish this task? The rasterizer is unfortunately only for 2D-data useful.

 

Without a transformer (Only Reader & Writer) the  the following error message occur:

 

 

Esri ASCII Grid Plugin: Failed to obtain raster from feature. Only features with raster geometry are expected.