Guidelines for editing features with base height properties in 3D

Available with 3D Analyst license.

There are many options for defining how features obtain a base height, or z-value, in 3D, and some of these are better suited to editing than others. This topic explains the most common combinations of base heights used to display features in 3D, and provides recommendations for the best settings to use when editing them.

The four most common elevation settings used in 3D are often described as:

1. On the ground
   • These features belong on the ground, such as trees.
2. Relative to the ground
   • These features know where they are compared to the ground, such as security cameras.
3. Floating on a custom surface
   • These features belong on a surface that is not the ground, such as where a well site intersects on top of a geologic body.
4. Absolute height
   • These features know their exact height, such as airplanes.

Each of these settings will correspond numerically to the labeled illustration below, as well as the table and other labeled images.

The four most common elevation settings used in 3D are numbered in this graphic and correspond to the table descriptions below.

Elevation settings when editing in 3D

The most appropriate classification choice depends on whether your originating features are 2D or 3D, and whether they need to rely on a surface or not. Use the image and table below to verify your elevation settings before editing in 3D.

Item	Base Height Classification	Example Use Cases	Elevation Source	Recommendations and Additional Information
1.	On the ground	light poles trees cars	The ground surface	This is the most common use case for base height settings.
2.	Relative to ground	security cameras well base points subway stations	The ground surface combined with feature driven z-values.
3.	Floating on a custom surface	intersection points (subsurface faults) site pollution levels ozone readings	A nonground (custom) surface	This assumes you are using features with no z-values (2D) and only have a surface to work from. By digitizing directly on the custom elevation source, the z-values are automatically derived. There is no height offset from the surface.
4.	Absolute	airplanes earthquake epicenters satellites	Feature driven z-values	In this case, the features are 3D meaning they already include a height value in their geometry. A surface is not required for display. Tip: If you are using an attribute then be sure it is a single value and not a complex expression.

A graphical representation of your base height settings for layers in 3D is also available on the Elevation tab in ArcGlobe (left side in the image below) and the Base Heights tab in ArcScene (right side in the image below). The graphic updates as the layer properties are changed, providing immediate feedback on how the data will be displayed.

The filled square in the feedback graphic for ArcGlobe (left) and ArcScene (right) represents the elevation settings you define in the Layer Properties page for Base Heights. The numbers used here correspond to the numbers used in the content above for the four most common settings.

Note:

Vertical offsets, where the elevation of the entire layer is changed using the layer offset property, are not supported while editing in 3D. Any layers in your 3D document that have layer offsets applied will be displayed as Editor Warnings when you start an edit session. If you continue with the edit session, your layers will automatically disable layer offsets until after the edit session has ended.