Systems, methods, and devices for computer-aided design, digital treatment planning, and direct additive manufacturing of dental appliances are provided. In some embodiments, a method includes receiving a treatment plan for a patient's teeth, the treatment plan specifying a target arrangement for the teeth and a plurality of treatment stages to reposition the teeth from an initial arrangement toward the target arrangement. The method can include identifying appliance design parameters for one or more dental appliances to implement at least one treatment stage of the plurality of treatment stages. The appliance design parameters can include one or more manufacturability parameters corresponding to an additive manufacturing process to be used to directly fabricate the one or more dental appliances. The method can further include determining an appliance geometry for the one or more dental appliances using the set of appliance design parameters.