Modeling Operations

Let's say you have a 2D drawing that you need to convert into a 3D object. Here comes extrusion! Extruding modeling operation relates to extending a shape, and you can define both the direction and the length. For example, extruding an arc will result in an open face.^[1]

Sweep path is a modeling operation that allows creating a shape from one or more cross-sections extended along a simple 2D path. In other words, the tool stretches a "skin" over the shapes in the cross-sections. What elements can you turn into a shell or a solid shape? It could be a vertex, edge, no matter open or closed, face, or wire.^[2] Such objects can be a part of more complex components used in mechanical engineering, 3D printing, and other related fields. 

You've definitely seen a picture of a tornado — or even a tornado itself — and can vividly imagine the whirlwind revolving around an invisible axis. That's how the revolution aka lathe works — rotates the object around a given axis and gets a symmetrical output shape. For example, by rotating an edge, you'll get a face, and by rotating the face, you'll come up with a solid shape.^[3]

The lathe operation took its name from a real machine tool that rotates a workpiece to create a symmetrical item. Lathes are widely used in woodturning, metalworking, metal spinning, thermal spraying, parts reclamation, and glass-working. The best-known appliance of a lathe tool is a potter's wheel for crafting ceramics. 

Have you ever seen how a woodworker, by cutting and polishing off the sharp, uneven edges of a log, crafts some exquisite details for furniture pieces? The bevel tool in 3D modeling does the same. It helps keep the edges of any object hard and sharp but realistic by chopping off the edges of a perfectly flat cube or other shapes. You can play around with shapes, tweaking the bevel amount and the roundness of edges.^[4] 

The flat bevel tool makes the corner or edge sloped or angled by cutting it off like a knife. You get a new face that you can adjust and make more or less sloppy, as well as more or less wider by fiddling around with the bevel amount. By adjusting the number of segments, you can come up with shapes of various angularity.

The real-world objects are rarely precisely sharp, and rounded corners are much more eye-pleasing. The round bevel tool in 3D modeling helps smooth edges for a more realistic look. It takes a point or a line of a shape and cuts it off like a knife. By adjusting the number of segments, you can come up with shapes of various roundness, remove unnecessary angles, and create a more realistic look of an object. 

Subdivision comes in handy when you are designing something intricate where each detail matters. The operation divides an object into all quads — multiple squares or rectangular polygons. They allow 3D artists to create bending and moving parts smoothly and sculpt shapes the way they like.^[5]

Boolean operations — intersection, subtraction, and union — are great time savers for crafting new shapes.^[6] The intersection of two or more solid objects means you get a new one while regions outside the overlapping area get cut off. This technique allows 3D artists to create clean-cut shapes without wasting too much effort and time. 

Subtraction follows the Jenga board game's principle — it removes the area of a shape from the one it's inside. In 3D modeling, you should specify which shape is the main one. The other shape, including the overlapping portion, gets removed. The technique removes the pain of cutting out the perfect shape manually. 

Union operation takes two solid objects and joins them together. Basically, the union works like glue when it sticks a broken handle to a coffee mug and takes two pieces into one. Like other boolean operations, this method is a good fit for creating complicated artificial forms like buildings, cars, or other objects.