If the 3D Component contains only geometry, (i.e. without excitation and boundary conditions) the Solution Type of the component does not matter. However, if the 3D component includes other aspects of an HFSS design such as excitations, Hybrid Regions, etc., the active Solution Type of the design must support those aspects of the 3D component. For example, if a 3D component is excited with Wave Port in Driven Modal Solution Type, it can only be inserted in a design with Driven Modal Solution Type. If you have a design which is supposed to be in Drive Terminal based on all other elements and excitations in the design and you want to insert a 3D component which is defined in Driven Modal, you should first edit definition of the 3D Component and make it compatible with the active Solution Type in your design. Note that this option is not available if the component is encrypted.