Concept: Site model modification
Difficulty level: Intermediate
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Tool |
Tool set |
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Site Modifiers
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Site Planning |
As discussed in Concept: Sitework overview, when the site model is generated, two different display modes of the site model object are available—existing and proposed. The existing site represents the site prior to your project; the proposed site incorporates the project’s changes. To modify the site model, use the Site Modifiers tool, along with other site modification tools in the Vectorworks program; a site modifier can be applied to either the existing or proposed site model, but it is normally applied to the proposed site modifier only. The differences between the existing and proposed site modifiers produce the cut and fill volume calculations for the site model object.
Each site modifier defines its own surface; the site model uses that surface as it generates the site model surface outside the modifier area. A site modifier can be nested inside another site modifier. Site model generation builds a hierarchy of nested modifiers, applies them in order, and stitches their surfaces together to produce the final site model surface.
Grade limits define the construction/modification area. It's helpful to create a grade limit around the whole site, and/or divide up the site into different areas using grade limits; you can nest one or more grade limits inside another grade limit. Site modifiers would have vertical edges if they were not enclosed within grade limits, which creates a transition to the area that is not modified. You can also use grade limits to protect areas on the site model that should not change, such as an existing building.
There are two types of modifiers: closed surface and open surface modifiers.
The closed surface modifiers—planar pad, pad with retaining edge, aligned, path, texture bed, and spoil pile—define a parametric surface inside a closed area. The grade limits closed modifier is an area containing surface modifications; the area defines the transition surface between the modifiers that lie inside the area and the rest of the site model surface.
Each of the closed surface modifiers provides its own surface, which is placed into its parent’s surface, ultimately producing the final site model surface.
The open surface modifiers—open edge line, pathway path, grade object, and stake object—ensure triangulation in the area matching the elevation along the lines of the open surface modifier (not necessarily along the contour lines).
The Site Modifiers tool has several modes.
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Mode |
Description |
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Grade Limits
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Defines an area of topographical transition between existing site data and the site modifiers enclosed within the limits |
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Open Edge Line
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Creates an open path site modifier |
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Planar Pad
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Draws a closed area which modifies the site model |
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Pad with Retaining Edge
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Creates a pad with an edge around it, allowing the terrain to be shaped around the pad |
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Aligned
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Creates an aligned pad that vertically matches the horizontal edges of surrounding modifiers. Aligned pads are complex, non-planar modifiers that can also be modified with vertical profiles, stake objects, and grade objects. |
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Pathway Path
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Creates a surface defined by one longitudinal profile and a set of transverse profiles, defined by a pathway/center line polyline and a specified width value |
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Boundary Path
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Creates a surface defined by one longitudinal profile and a set of transverse profiles, defined as a boundary polyline with a center line based on the boundary |
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Texture Bed
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Creates an area of the site model that can be textured |
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Spoil Pile
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Creates an area where excess earth can be used to help balance the cut and fill |
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Snap to Contour Elevation
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Constrains the site modifier to the site model contour elevation under the cursor when the site modifier is created. The contour under the cursor is highlighted, and the elevation of that contour is used as the modifier elevation. |
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Polyline creation options |
Selects the method for drawing the polyline upon which the site modifier is based; see Creating polylines |
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Preferences
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Sets the default preferences for the site modifier |
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Pad Elev |
Specifies the initial elevation of the site modifier |
Site modifiers can be placed on any layer. The site model properties specify whether modifiers in another layer can affect the site model (see Creating the site model). You might put various site modifiers on separate layers, for example, so that you can show each modifier's effect on the site model individually. When a site modifier is placed in the drawing, the Site-DTM-Modifier class is created automatically.
In addition to the site modifiers that are created with the Site Modifiers tool, a number of other tools and commands create objects that can modify the site model.
