Scheme-it supports a list of primitive custom symbol types that allow you to create your own component symbols. To place a custom symbol primitive into your layout, click on the "Custom Symbol" category in the left sidebar and drag in the desired primitive. Custom primitives include the Part Body and the Pin.
The Part Body primitive is used as the basis for creating a basic symbol body. Shapes include rectangle, rounded rectangle, and triangle. When a Part Body primitive is placed in your diagram, it is automatically added to the project BOM.
Pin primitives allow you to drag in generic port pins for use in creating custom symbols. Port pins include top, left, bottom, and right positioned pins. Port pins contain wire nodes that allow you to connect them to other symbol pins.
You must drag a pin out of the sidebar onto an existing part body. When you do so, the pin is placed on the side of the part body designated by the type of pin. The drop location determines the vertical or horizontal position of the pin on the symbol.
Pins may be moved along the symbol side they are placed on. Pins may not be moved to a different side of the symbol. To move a pin, delete the pin and add a new one on the desired side.