When modeling a circular object or other non-flat surface, you can add holes and other details using Knife Cut and Loop Tools. But it will usually break the perfect surface smoothness. One solution is to keep a smooth subdivided version of the base shape and use a Shrinkwrap modifier on a more detailed duplicate. Follow Blender Secrets on Youtube https://www.youtube.com/c/BlenderSecrets Free Sample PDF https://mailchimp.blendersecrets.org/freesample Full Blender e-book with free updates https://