Terrain

Displays the name of the terrain object. The software uses the name of one of the selected objects to name the terrain object.

Pick Operand—Adds splines to the terrain object. You might do this if you didn't select all the objects before generating the terrain object, or if some objects in the imported data weren't included in the terrain object. You can also use this option to add existing splines in the current scene to the terrain object.

When you click Pick Operand, the copy method you designate determines how the operands are used. When Move is the method, the original contour data is moved from the scene and into the operands of the new terrain object. Copy, Reference, and Instance retain the original contour data in the scene and create copies, references or instances of the contour data as operands in the terrain object. This is similar to the copy method for Boolean.

Override—Allows you to select closed curves that override any other operand data within their interior. Within the area an Override operand encloses (as seen in plan), other curves and points of the mesh are disregarded and the elevation of the Override operand supersedes them. An Override operand is indicated in the operands list by a # after its name. Override is only effective on closed curves. If multiple override operands overlap, later overrides (higher operand numbers) take preference.

Operands—Displays the current operands. Each operand is listed as "Op" followed by a number and the name of the object that is being used as the operand. The operand name comprises layer, color, or object type name plus a numeric suffix.

Delete Operand—Deletes a selected operand from the Operands list.

Graded Surface—Creates a graded surface of the mesh over the contours.

Terrain created as a graded surface

Graded Solid—Creates a graded surface with skirts around the sides and a bottom surface. This represents a solid that is visible from every direction.

Layered Solid—Creates a "wedding cake" or laminated solid similar to cardboard architectural models.

Terrain created as a "layered solid" surface, with levels

Stitch Border—When on, suppresses the creation of new triangles around the edges of terrain objects when edge conditions are defined by splines that are not closed. Most terrain forms display more reasonably when this is turned off.

Retriangulate—The basic Terrain algorithm tends to flatten or notch contours when they turn sharply upon themselves. A typical situation in which this may happen is when a narrow creek bed is described with contours; the resulting form may look more like a series of cascades at each elevational contour, rather than a smoothly descending ravine. When Retriangulate is checked, a somewhat slower algorithm is used that follows contour lines more closely. This may be particularly evident in the Layered Solid display mode. For additional precision, try using Retriangulate in conjunction with horizontal interpolation.

Terrain—Displays only the triangulated mesh over the contour line data.

Contours—Displays only the contour line data of the terrain object.

Both—Displays both the triangulated mesh and the contour line data of the terrain object. You can select the terrain object by clicking its surface, but not by clicking a contour line. When Both is selected, contour lines may not be apparent in Wireframe display modes or when Edged Faces are displayed.

The items in this group box determine when the software recalculates the projection for the terrain object. Because complex terrain objects can slow performance, you can use these options to avoid constant calculation.

Always—Updates the terrain object immediately when you change an operand, including the original object of an instanced or referenced operand.

When Rendering—Updates the terrain object when you render the scene or when you click Update. With this option, viewports won't show current geometry unless you click Update.

Manually—Updates the terrain object when you click Update.

Update—Updates the terrain object. This button is not enabled only when Always is the active option.

No Simplification—Uses all the operands' vertices to create a complex mesh. This results in greater detail and a larger file size than the two fractional options.

Use 1/2 of Points—Uses half the set of vertices in the operands to create a less complex mesh. This results in less detail and a smaller file size than using No Simplification.

Use 1/4 of Points—Uses a quarter of the of vertices in the operands to create a less complex mesh. This results in the least detail and smallest file size of these options.

Interpolate Points * 2—Doubles the set of vertices in the operands to create a more refined but more complex mesh. This is most effective in terrain forms that use constructive curves such as circles and ellipses. This results in more detail and a larger file size than using No Simplification.

Interpolate Points * 4—Quadruples the set of vertices in the operands to create a more refined but more complex mesh. This is most effective in terrain forms that use constructive curves such as circles and ellipses. This results in more detail and a larger file size than using No Simplification.

No Simplification—Uses all the spline operandsvertices of the terrain object to create a complex mesh. This results in greater detail and a larger file size than the other two options.

Use 1/2 of Lines—Uses half the set of spline operands of the terrain object to create a less complex mesh. This results in less detail and a smaller file size than using No Simplification.

Use 1/4 of Lines—Uses a quarter of the of spline operands of the terrain object to create a less complex mesh. This results in the least detail and smallest file size of the three options.

Maximum Elev.—Displays the maximum elevation in the Z axis of the terrain object. The software derives this data from the contour data.

Minimum Elev.—Displays the minimum elevation in the Z axis of the terrain object. The software derives this data from the contour data.

Reference Elev.—This is the reference elevation, or datum, that the software uses as a guide for assigning colors to zones of elevation. After entering a reference elevation, click the Create Defaults button. The software treats elevations above the reference elevation as solid land and those below the reference elevation as water.

If you enter a value no greater than the minimum elevation in the object, the software divides the range between the reference and minimum elevations into five color zones: dark green, light green, yellow, purple, and light gray.

If you enter a value between the minimum and maximum elevations, the software creates six color zones. Two zones (dark blue and light blue) are used for elevations below the reference elevation. These are considered to be under water. One zone (dark yellow) is used for a narrow range around the reference elevation. Three zones (dark green, light green, light yellow) are used for elevations above the reference elevation.

If you enter a value at or above the maximum elevation, the software divides the range between the minimum and reference elevations into three zones (dark blue, medium blue, light blue).

Create Defaults—Creates elevation zones. The software lists the elevation at the bottom of each zone, referenced to the datum (the reference elevation). The software applies the color of the zone at the base elevation. Whether the colors blend between zones depends on your choice of the Blend to Color Above or Solid to Top of Zone option.

The items in this group box assign colors to elevation zones. For example, you might want to change levels of blue to indicate the depth for water. Your changes in the Color Zone area don't affect the terrain object until you click the Modify Zone or Add Zone button.

Base Elev—This is the base elevation of a zone to which you assign color. After entering a value, click Add Zone to display the elevation in the list under Create Defaults.

Base Color—Click the color swatch to change the color of the zone.

Blend to Color Above—Blends the color of the current zone to the color of the zone above it.

Solid to Top of Zone—Makes a solid color at the top of the zone without blending to the color of the zone above it.

Modify Zone—Modifies selected options of a zone.

Add Zone—Adds values and selected options for a new zone.

Delete Zone—Deletes a selected zone.