From the course: 3ds Max 2024 Essential Training

Understanding subdivision surfaces - 3ds Max Tutorial

From the course: 3ds Max 2024 Essential Training

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Understanding subdivision surfaces

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Subdivision Surface Modeling is a technique to create smooth flowing surfaces such as a character, creature, or even the soft cushions of this office chair. In this scene the seat cushion is an active, open, subdiv object. I can change its level of detail at will while preserving its overall shape. The other objects have all been baked or converted to editable poly. To see this more clearly let's enable Edged Faces with F4. Although the seat cushion at the bottom looks round and smooth, it doesn't actually appear to have as many polygon wires. Well that's just due to the display mode that we're in. Let's investigate. Select that seat cushion, go over to the Modify panel, and we see that the stack consists of an editable poly base object. Above that there's a symmetry modifier That will reflect the polygon surface to the other side so that we only have to model half of the object. At the top of the stack is the Open Subdiv modifier. Its function is to subdivide the polygons on the base object. Not only that, but it averages the angles among the new subdivided polygons to smooth out any jagged corners. If we disable that top modifier by clicking on the visibility or eye icon. We see the original polygon mesh. This is what is known as a control cage. It's merely a means to an end. We're never going to actually render or export this low level of detail mesh. We use that control cage as a tool to sculpt with subdivision surfaces. Ok, I'll re-enable Open Subdiv. If we want to see the actual level of detail or the individual polygons after they've been subdivided, we can disable this option here, IsoLineDisplay. Turn that off. And now we're seeing all of the individual subdivided polygons on the object. We can zoom in on the selection with the Z key. The most important parameter of a subdivision algorithm is its number of iterations, or number of repetitions. This is the number of times a mesh will be subdivided. If we change the number of iterations we increase or decrease the level of detail. Bring that down by clicking on the spinner. So with an iterations of 1 we have a blockier object. With an iterations of 0 we have the original control cage or the original polygon mesh. As we increase the iterations value we get more detail on the surface. An iteration value of 2 or 3 is usually optimal. You see, if I take it up to a value of 5, I've got an extremely dense mesh here, and that's overkill. We don't need that. I'm going to bring this back down to what I had, which was a value of 2. Subdivision surfaces have been implemented in several ways in 3ds Max. It's been around for a while, and so the design of the software implementation has evolved over time. The OpenSubdiv modifier is generally the optimal workflow because it has the best performance and the best compatibility with other applications. It's based upon an open standard, the Open Subdivision Surface Standard. We can also subdivide meshes with other modifiers. In the modifier list we have several other ones. We've got something called Mesh Smooth. There's also one called Turbo Smooth, which, as the name implies, is a little bit faster. And there's even one called HSDS, which stands for Hierarchical Subdivision Surfaces. Any of these will perform more or less the same function, but OpenSubdiv is faster and better. So I'm not recommending that you use those other modifiers. And in fact, if you see a tutorial that references those other modifiers, I do recommend that you use OpenSubdiv instead. Subdivs are also built directly into the EditablePoly object and the EditPoly modifier. That can come in handy sometimes, but in most cases the workflow I'll be demonstrating with the OpenSubdiv modifier is the most effective and flexible. That's a basic introduction to the concepts of subdivision surfaces and how they're implemented in Max.

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