Expand/Shrink Shells

Form:  Expand/Shrink Shells

Use the Edit menu > Edit Shells > Expand/Shrink Shells command to expand or shrink a floor-type (horizontal) shell object.

1.   Select a floor-type (horizontal) shell object.

2.   Click the Edit menu > Edit Shells > Expand/Shrink Shells command to access the Expand/Shrink Shells form.

3.   On the Expand/Shrink Shells form, enter the desired Offset Value to move each edge of the shell object in a direction perpendicular to the edge:

• Positive offset values: Cause the edges to move away from the interior of the shell floor object; that is, they expand the object.

• Negative offset values: Cause the edges to move toward the interior of the shell object; that is, they shrink the object.

4. Click the Apply button. When the Apply button is used, the Expand/Shrink Shells form will remain open until it is closed by clicking the Close button. This allows another shell object(s) to be selected for editing. If only one set of objects is undergoing only one set, the OK button can be used to both apply the edit and close the form.

Note: If a negative offset value that causes the shell object to collapse on itself is specified, the command is ignored and the object is not shrunk. Example

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Shell Object Edge Select Mode

Typically when you select a floor-type shell object and use the Edit menu > Edit Shells > Expand/Shrink Shells command, all sides of the shell object are moved. It is possible to select one or more sides of a shell object individually and have the Edit menu > Expand/Shrink Shells command apply only to the selected sides of the shell object. Use the following steps to do this:

1. Make the active window a Plan View using the View menu > Set Plan View command or the Plan View toolbar button.

2. Click on the edges of the shell object that is to be expanded or shrunk. ETABS displays the number of edges selected in the status bar at the bottom of the ETABS window.

3. Click the Edit menu > Edit Shells > Expand/Shrink Shells command, which brings up the Expand/Shrink Shells form.

4. On the Expand/Shrink Shells form, enter the desired Offset Value to move each edge of the shell object in a direction perpendicular to the edge.

5. Click the Apply button.  When the Apply button is used, the Expand/Shrink Shells form will remain open until it is closed by clicking the Close button. This allows another shell object(s) to be selected for editing. If only one set of objects is undergoing only one set, the OK button can be used to both apply the edit and close the form.