About Shells

Basic Shell Creation

Shells can be created in either the Floor Plan or 3D Window. Use one of three basic shapes:

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Creating a basic Shell of any of these types is easy. Then you can develop the Shell further by graphically editing it, freely rotating it, adding openings or cutting its contour into any shape.

See Graphical Editing of Shells.

Shell Structure

Like other construction elements, a Shell’s essential structure derives from its Building Material, assigned in Shell Tool Settings.

A Shell (like a Wall, Slab or Roof) can have a composite structure. If the structure of the Shell is a composite, then the Shell’s thickness is defined in Options > Element Attributes > Composites, and equals the sum of the skins’ thicknesses.

For a composite Shell, the “Reference Side” surface is the first listed skin of the composite, in Composite Settings.

Note: You can edit a selected composite by accessing its settings from its context menu:

The Shell is constructed out of a membrane (the Reference side) plus a Shell body attached to one side of the membrane. The Shell body is “grown downwards,” with the Reference side on top.

The Reference side of the Shell is significant when:

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calculating surface area of the Shell or its skins

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overriding surfaces as needed, in the Model Panel of Shell Settings.

Use Flip (from Shell Settings or the Info Box) if you want to move the Shell body to the other side of Shell membrane.

Shell Display on the Floor Plan

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Shell display on the Floor Plan is based on its real 3D geometry. Thus, you will see the effects of Solid Element Operations on Shells on the Floor Plan.

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Shells can display a cover fill, which - as with Roofs - can be set to reflect the vectorial hatching of the Shell’s surface, either as defined in the Building Material or (if the override is on) its top surface override. (Enable the Use Fill from Surface checkbox under the Cover Fill settings, in Shell Settings.)

Shell Connections

For information on how intersections (junctions) work among construction elements, including Shells:

See Element Intersections and Merge Elements: Roofs, Shells, Morphs.

Like Roofs, Shells are trimming elements and participate in associative model connections. This means you can trim Shells to other elements to achieve precise geometries and complex structures.

See Trim Elements to Roof or Shell.

Holes and Skylights can be placed into Shells.

See Create Hole in Shell and Skylights.

Gravitate to Shell

ARCHICAD’s Gravity feature works on Shells. That is, when placing a new Wall, Column, Beam or Object-type element, the Gravity function lets you place it directly on top of an existing Shell, thus taking on the elevation of the element it is placed on.

See also Gravity.