Link to YouTube Tutorial: http://youtu.be/x94SL3sHV-k
The current workflow to reinforce structural elements from Revit to AutoCAD Structural Detailing is currently limited to ‘standard’ objects such as beams, columns etc via the Revit Structure extensions. You may be interested in a process that I have discovered to take any object modelled in Revit Structure and then create the required formwork drawings in AutoCAD Structural Detailing and then add the reinforcement. I have used Revit Structure to model a slab but you could use any solid modelling software to produce your required geometry. Below you can see the drafting view imported into Revit Structure from ASD.
I have started in Revit Structure by creating a slab and then adding a slab edge and an in-place model of a thickening.
I can then save this as an ACIS solid and then import this into ASD (see the YouTube video for details). You will need to Union all of the solids to create a composite model. Type in UNI on the command line and select all the geometry. One this is done you can then select the Use 3D solids command in ASD.
This will then produce the required formwork in ASD and I can proceed to reinforce the slab and take the drawing back into Revit Structure by linking the 2D drawing into a drafting view. This means that if you update the reinforcement in ASD the drafting view will also update in Revit Structure.
Here is the link to the YouTube Tutorial: