Adding hair to Cinema 4d can be done in a few different ways. The first way is to use the Hair module that comes with Cinema 4d. This module allows you to grow hair on any object, and then style it using various tools.
Another way to add hair to Cinema 4d is by using the Hair From Points tool. This tool allows you to create hair from any point cloud data, which means you can use it on scanned 3d models or photographs.
Finally, you can also add hair manually by creating curves and then converting them into Hair objects. This method gives you the most control over the shape and look of your hair, but it's also the most time-consuming.