- Surface Development Using the MeshSmooth Modifier
- MeshSmooth Modifier Rollouts
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MeshSmooth Modifier Rollouts
The MeshSmooth rollouts found in the Modify command panel provide a deeper level of surface development control. There are seven MeshSmooth rollouts—the four most basic rollouts used to control the NURMS subdivision method will be covered (see Figure 8).
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Figure 8 The commands and controls in the MeshSmooth rollouts control the way MeshSmooth affects your model surfaces and how the resultant effect appears in rendered images.
Understanding the controls in each of these rollouts requires experimentation and an understanding of some of the other features in max 4, such as Smoothing Groups and Soft Selection. A brief overview of the four most basic rollouts will help you along the way.
Exploring the Subdivision Method Rollout
There are three subdivision methods to choose from: NURMS, Classic, and Quad Output. Figure 9 shows the Subdivision Method rollout. Click the arrow in the drop-down menu to select the method of your choice. NURMS is the method covered in this article. Consult your User Reference for complete details on the other two subdivision methods.
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Figure 9 NURMS is the default subdivision method in max 4 and gives you greater control over the final form you are trying to achieve.
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Your 3ds max 4 User Reference includes a detailed description of differences between the subdivision methods. Use the keyword MeshSmooth Modifier to access the information. The information can also be found in Volume 1, page 504, of your user manuals. The Tutorials manual that came with your software also has an excellent tutorial on the use of MeshSmooth on page 431.
NURMS is the acronym for Non-Uniform Rational MeshSmooth. Similar in capability to NURBS, NURMS surfaces allow you to control surface shape and detail by adjusting the weight and crease values of the vertices and edges that define the surface.
Understanding the Subdivision Amount Rollout
When MeshSmooth is applied, it increases the complexity of the surface mesh by adding extra faces at every edge and vertex. The subdivision values in this rollout control the amount of subdivision applied to your surface mesh (see Figure 10).
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Figure 10 There are two Iteration settings in the Subdivision Amount rollout—one for the mesh displayed in your viewport and one for the rendered imagery.
Iteration Values and max 4 Performance
Higher iteration values create denser mesh and higher polygon counts, which significantly impact your viewport navigation and rendering performance. Keep your display Iteration amount set to 1 or 2 maximum—and set your Render Values Iteration amount to 4 or less. You can specify higher values in both, but be prepared for significant degradation in max's performance (see Figure 11).
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Figure 11 The difference between higher and lower Iteration amounts in the Render Values section is mainly visible in the edges and corners of the rendered surfaces. Lower values yield faceted/blocky edges. Higher values produce smoother edges and corners.
Understanding Smoothness
The Smoothness value determines the number of faces that are added to the corners and edges of your model. It does this by averaging the angles of all the edges that connect to a vertex. When Smoothness is set to 0, MeshSmooth prevents the creation of any additional faces surrounding the vertices that create edges or corners in the mesh. If the smoothness value is set to the default maximum value of 1, MeshSmooth adds faces to all the coplanar vertices in the mesh surface, edges, and corners (see Figure 12).
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Figure 12 A smoothness value of .5 negates the effect of MeshSmooth, regardless of the iteration value.
At first the Smoothness value seems to be of little use (see Figure 13), but further exploration shows that it can yield some interesting faceted effects (see Figure 14).
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Figure 13 To force the rendered imagery to show the facets on the box surfaces, the Faceted selection was checked in the Material Editor Shader Basic Parameters rollout of the material applied to these boxes.
Figure 14 It's important to learn more about the synergy between the Iterations, Smoothness, and Material Editor settings. Try some experiments of your own to understand their interdependence.
The functional purpose of Smoothing is to allow you to adjust where the MeshSmooth effect is applied to an object's surface. A setting of 1 applies the effect to all surfaces of the object. Lower settings apply it just to the edges and corners, without creating more geometry in the flat surfaces that don't need to be smoother to be acceptable. The resultant artistic effect—the creation of interesting faceted edge details—is more important to your day-to-day process.
Working with the Local Control Rollout
The Local Control rollout is the heart and soul of the MeshSmooth control toolbox. The commands in the rollout allow you to select and modify the individual vertices and edges controlling the MeshSmooth effect, giving you a deeper level of modeling control and detail refinement.
The controls in this rollout do not affect the source object that was used to create the Reference clone—they affect only the surface development of the object to which MeshSmooth has been applied (see Figure 15).
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Figure 15 You can modify the local control vertices and edges by using the standard transform commands—Move, Rotate, and Scale—and by adjusting their Weight and Crease values.
The selection status display shows you the number and type of the currently selected subobjects. The basic process to use the controls in this rollout begins by clicking either Vertex or Edge. The following sections explain each part of this important rollout.
Subobject Level
The MeshSmooth subobjects are exactly the same as their Edit Mesh counterparts, except for one critical difference: The number of vertices and edges in the mesh is variable. When a subobject is active, you can modify it by using the transform commands and adjusting the Weight and Crease values. Figure 16 shows the effect that using transform commands on selected vertices can have on surface development.
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Figure 16 A similar, more subtle effect can be achieved by changing the Weight of the selected vertices.
Rotating the selected vertices produces the twist in the form seen in Figure 17.
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Figure 17 Twist is a parametric modifier that can be applied to an object to achieve a similar effect. Transforms can be animated to create any number of living organic effects, such as a beating heart, chest expansion during breathing, muscle contraction, and so forth.
Figure 18 shows the effect that rotating and scaling eight selected edges can have on surface development.
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Figure 18 Transform commands operate on the edges and vertices of the surface geometry. Using the reset commands in the Resets rollout can reverse the effect of the transform changes you make.
Ignore Backfacing allows you to select the vertices and edges on surfaces that are facing your POV, while ignoring those on the back side of the surface. This is especially useful when using the selection region method to select multiple subobjects (see Figure 19).
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Figure 19 When Ignore Backfacing is on the vertices in the back surfaces, the box will not be selected by the selection region.
Control Level
Control Level allows you to access and use the increased number of vertices and edges created by higher Iteration values to refine your model's surface details (see Figure 20).
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Figure 20 Higher control level amounts give you more subobjects to work with but don't affect the iteration amounts in the viewport or rendered imagery.
Control Level is linked to the Iterations amount. If Iterations is set to 3, the highest Control Level value you can specify is 3. One of the most useful aspects of the control level is that MeshSmooth keeps track of the specific changes made to the mesh subobjects in all the levels available.
For example, a mesh that has an Iterations value of 3 gives you four control levels: 0, 1, 2, and 3. You can select and modify vertices and edges on control level 1, change to level 2, and continue modifying additional subobject selections; change to level 0 for another round of modifications; and so on. MeshSmooth keeps track of the control levels and the related changes associated with each one. A major benefit of this history-keeping aspect of MeshSmooth is that it also allows you to reset specific changes level by level.
Crease
The Crease function works only when an edge is selected as the subobject. It's used to create sharp transitional edges in your model's surface. The highest crease value is 1, and 0 is the default. Figure 21 shows the effect of a Crease value of 1 on 48 selected edges.
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Figure 21 You can exaggerate the Crease effect by using the transform commands on the selected edges. The edges in this image were also scaled down to increase the depth and severity of the crease.
Weight
Adjusting the Weight values for selected vertex and edge subobjects in the control mesh changes the form of the object you are working with without changing the actual location of the subobjects.
Weight values lower than the default value of 1 push the surface away from the selected vertex or edge. Higher Weight values pull the surface closer to the selected subobject (see Figure 22).
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Figure 22 Moving the top center vertex of the control mesh down made the dimple in the middle of the pillow shape in this image. Adjusting the Weight value creates subtle organic transitions in your surface development.
Digital Eraser: The Resets Rollout
Sometimes it seems that the eraser on a pencil is more important than the lead. For the same reason, whiteout is one of the greatest boons to mankind. All joking aside, knowing that you can easily correct mistakes lets you take more risks in your max work. Figure 23 shows the MeshSmooth Resets rollout—it's the eraser on the MeshSmooth pencil.
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Figure 23 The controls in the Resets rollout allow you to experiment without fear. Using the appropriate reset command, you can easily reverse the effects of your experimentation.
Understanding what each one of the reset commands does is important:
Reset All Levels—When this selection is active, the Resets command buttons will affect all the control levels in your mesh. This means that if MeshSmooth Iterations is set to 3 and you click Reset Geometric Edits, all the vertex and edge transforms that you've made in all four of the control levels will be reset to their original parameters.
Reset This Level—When this selection is active, the Resets command buttons will affect only the changes you've made in the currently specified control level.
Reset Geometric Edits—Geometric Edits are any changes that you make to the vertex and edge subobjects using the move, rotate, and scale transform commands.
Reset Edge Creases—This resets the edge creases back to their default parameters.
Reset Vertex and Edge Weights—This resets vertex and edge weights back to their default parameters.
Reset Everything—Want to start from scratch? Be careful! This command erases all modifications for the currently selected level or all the levels.
Three rollouts weren't covered in this article: Soft Selection, Parameters, and Settings. Soft Selection is a different way of selecting subobjects and subsequently animating and controlling the modifier effects that are applied to the selection.
The Parameters and Settings rollouts contain some controls that are specific to subdivision methods other than NURMS. The rest of the sections in this rollout deal with optional ways MeshSmooth operates and smoothes the resultant mesh of your model surfaces. You'll learn more about these additional controls as you use them in your max work.
Because of its power and ease of use, MeshSmooth has become my everyday choice for modeling organic forms and objects that require sophisticated surface development. Experiment and have some fun—it's a great tool!