Table 6.237—DRM_Rendering_Priority_Level
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Property |
Description |
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Superclass |
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Class |
· <DRM Rendering Priority Level> |
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Subclass |
· none |
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Definition |
An object of this DRM class specifies a method used to describe the relative priority used to resolve occlusion between two or more overlapping (or potentially overlapping) objects. Priority is indicated by the group ID (rendering_group) and priority index (rendering_priority). The rendering_priority is relative to the rendering_group, and is intended to assign priority order (or layer) to coplanar <DRM Polygon>s or coplanar <DRM Feature>s. A higher index indicates a higher rendering priority (rendered last). Objects that do not contain a <DRM Rendering Priority Level> are assumed to have a rendering priority value of zero. |
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Example(s) |
· A particular SEDRIS transmittal may model a lake as a single <DRM Polygon> located inside of a much larger <DRM Polygon> that represents the surrounding terrain. The larger terrain polygon and the smaller lake polygon that it contains may be coplanar, so the modeler assigns a <DRM Rendering Priority Level> of one to the terrain <DRM Polygon> and a <DRM Rendering Priority Level> of two to the lake <DRM Polygon>, so that the lake polygon will be rendered on top of the terrain <DRM Polygon>. · The side of a <DRM Model> can be represented by a brown <DRM Polygon>, and a window in the side of a <DRM Model> can be represented by a grey <DRM Polygon> where the grey <DRM Polygon> is coplanar with the brown <DRM Polygon>. The grey <DRM Polygon> would be given a higher <DRM Rendering Priority Level> than the brown <DRM Polygon> so that the window would be drawn correctly on the side of the <DRM Model> (where the <DRM Model> could be either a building or a vehicle). · A Plan View Display (PVD) can display <DRM Point>, <DRM Areal Feature>s, and <DRM Linear Feature>s. Since <DRM Feature>s are usually considered to be 'flat', many features are, by definition, coplanar. A <DRM Rendering Priority Level> can be used to indicate the relative drawing order (or layer) within a set of overlapping <DRM Feature>s. For example, it is common for a single <DRM Areal Feature> to cover the entire <DRM Environment Root> area as a 'default, background' <DRM Feature>. This <DRM Areal Feature> could be given a rendering priority of -32768 so that it would always be drawn first, so that it would always be in the background. · The following instance diagram shows how <DRM Rendering Priority Level> can be used to override the layering of a fixed list of objects. The objects would render in this order: Polygon_C, Polygon_B, Polygon_A, Polygon_E, Polygon_F, Polygon_D.
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Inherited field elements |
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Field elements |
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Associated to (one-way) (inherited) |
· none |
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Associated to (one-way) |
· none |
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Associated by (one-way) (inherited) |
· none |
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Associated by (one-way) |
· none |
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Associated with (two-way) (inherited) |
· none |
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Associated with (two-way) |
· none |
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Composed of (two-way) (inherited) |
· none |
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Composed of (two-way) |
· none |
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Composed of (two-way metadata) (inherited) |
· none |
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Composed of (two-way metadata) |
· none |
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Component of (two-way) (inherited) |
· none |
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Component of (two-way) |
· none |
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Constraints |
· none |
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Notes |
1 Establishes a group to which objects' priorities are relative. 2 Indicates priority between coplanar objects. A higher value indicates a higher priority (i.e., a polygon with a value of 2 is "on top" of a polygon with a value of 1). |
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Class diagram |
