Miscellaneous Modifiers


Several of the Mesh Editing modifiers are unique, special-purpose modifiers. The Edit Normals modifier, for example, lets you change the direction of face normals, which doesn't really change the geometry, but it can have a big impact on how the object is smoothed and shaded.

Edit Normals

The Edit Normals modifier enables you to select and move normals. Normals appear as blue lines that extend from the vertex of each face. The Edit Normal modifier includes a Normals subobject that you can select and change its direction. To move (or rotate) a normal, you can use the transform tools on the main toolbar. If your viewport has shading enabled, you can see the effect of moving the normals.

You can select normals by Normal, Edge, Vertex, or Face. Selecting normals by Face, for example, selects all normals attached to a face when you click on a face. Moving a normal then moves all selected normals together.

You also have options to Ignore Backfacing and to Show Handles. Handles appear as small squares at the top of the normal vector. The Display Length value defines the length of the normals displayed in the viewports. Figure 16.12 shows all the normals extending from a simple Box object.

The modifier also includes buttons to Unify and to Break selected normals. Unify causes all selected normals to be combined to a single normal, and Break splits unified normals into their separate components again. The direction of the unified normal is an average of the surface points when unified or an average of the normals if the Unify/Break to Average option is enabled.

The Average Selected button averages all selected normals that are within the specified value if the Use Threshold value is enabled. If it is not enabled, then all selected normals are averaged. The Average Target button lets you interactively select a normal and then click on another normal to average. The Target normal must be within the specified Target value.

image from book
Figure 16.12: The Edit Normals Parameters let you work with normals

The direction of selected normals can be copied and pasted between normals. The Specify button marks a normal as a Specified normal. These normals appear cyan in the viewport and ignore any smoothing group information associated with the vertex. Explicit normals are green in the viewport, which denotes a normal that has deviated from its regular position. The Make Explicit button can be used to make normals explicit, thereby removing them from the normal computation task. The Reset button returns a normal to its regular type and position. At the bottom of the Parameters rollout is an information line that displays which normal is selected or how many normals are selected.

Normal modifier

The Normal modifier is the precursor to the Edit Normals modifier. It enables object normals to be flipped or unified. When some objects are imported, their normals can become erratic, producing holes in the geometry. By unifying and flipping the normals, you can restore an object's consistency. This modifier includes only two options: Unify Normals and Flip Normals.

STL Check modifier

The STL Check modifier checks a model in preparation for exporting it to the StereoLithography (STL) format. StereoLithography files require a closed surface: Geometry with holes or gaps can cause problems. Any problems are reported in the Status area of the Parameters rollout.

This modifier can check for several common errors, including Open Edge, Double Face, Spike, or Multiple Edge. Spikes are island faces with only one connected edge. You can select any or all of these options. If found, you can have the modifier select the problem Edges or Faces, or neither, or you can change the Material ID of the problem area.




3ds Max 9 Bible
3ds Max 9 Bible
ISBN: 0470100893
EAN: 2147483647
Year: 2007
Pages: 383

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