Shadow Box is a sculpting tool that lets you create 3D base meshes by drawing 2D silhouettes from three orthographic views: Front, Side and Bottom.

Shadow Box is designed primarily to quickly create a base mesh for sculpting. Once the initial shape is generated, you can continue refining it using Blender's sculpting tools.

Yes. You can sculpt or edit the generated mesh. If you want to use the Shadow Box tools again, you can choose whether to rebuild the mesh from the original masks or update the masks from the modified mesh.

Yes. The Reference Image to Mask feature can generate a mask from either the image's Alpha channel or its Luminance. You can then Add, Subtract or Replace the existing mask.