You can edit rebar shape families to specify various constraints, bars, and enable multi-planar placement.
To edit a selected rebar instance, click Modify | Structural Rebar tab 
Mode panel 
(Edit Family). Edit rebar shapes as you would other families. However rebar shapes possess additional tools for editing which have several requirements and limitations. These include the following:
- Rebar does not flex when its parameter values are adjusted.
- Rebar does not move in the family environment as it does in the project environment.
- Rebar has a single level of detail. Changing between Coarse, Medium, or Fine levels of detail have no effect on its appearance.
- Reference planes and dimensions that are not used to define the rebar shape will be silently removed from the family.
The tools described in this section are available when a shape family is opened for editing.