Nothing appears to happens when I run a "Design Selection" command. Why is this?

Question

If we right click a member in the active scene view, the context menu display two design options - Design Member and Design Selection. When we use the Design Member command on a member it automatically chooses a suitable section from the design section order list. However, if we use Design Selection it seems like nothing happens. Why is this?

 

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Answer

The Design Selection command like any of the Design commands on the Design tab and the Design plane, Design sub structure, Design members or Design Group command accessible via the right click context menu in the Structure or Group window, work in the same way. They only design the members and hence size them from the specified design order file or choose new reinforcement in concrete objects, if the Autodesign property is checked (on). This is to ensure that work already undertaken in rationalizing the section sizes and optimizations in stud spacings, web openings etc. are not undone by accident when the selected elements (and potentially elements elsewhere in the model but in the same design group), are designed.

The Design Member command offers a slightly different functionality, and will design the member (and other members in the same design group) and hence size it from the specified design order file, irrespective of the Autodesign property.

For a more detailed answer covering each design command, please refer to the information below.

More detailed information

There are essentially three ways to perform a design:

1. Perform one of the design commands on the Design tab. These commands perform the analysis and design/check of every member in the model.
2. Perform the design on a sub-set of members by:
   1. You can right click a sub folder in the Project workspace > Structure window, to expose a Design command. These exist on the Structure, Levels, Frames, Slopes, Sub Structures and Members folders. A similar option exists in the Groups window for a selected Group.
   2. Carry out a manual selection of members (and their associated groups, if being used) in the active scene view and via the right click context menu use the Design Selection command.
3. Perform the design of an individual member (and its associated group, if being used) via the right click context menu Design Member command.

Each one is briefly discussed below.

1. Design command via the Design tab

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When you perform a Design command from the Design tab, the program will auto design from the chosen design section order file if the Autodesign property is checked.

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If the Autodesign property is unchecked then the specified section is checked.

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What happens to the Autodesign property after a design, is controlled via the Design tab > Options > Autodesign page. The default is shown below.
 

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For steel/cold formed members, the default is to always remove the check from the Autodesign property after the design has been performed, whereas for concrete members, the Autodesign property will remain checked.

Tip. You can use the Review view regime > Show Alter State > Autodesign command to quickly show and alter the state of the Autodesign property.

2a. Design plane, members, sub structures, groups

The Design plane, Design sub structure, Design member command can be performed on a subset of members by right clicking one of the branches of the Project Workspace > Structure window and choosing Design Plane, Design sub structure or Design members from the context menu. You can also right click a group on the Group window and choose Design Group.

 

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The design is based on the analysis results from a previously run analysis/design. Hence, a design via the design tab or an analysis via the Analyse tab, needs to have been performed beforehand, so that design forces exist.

The Design plane, Design sub structure, Design members or Design Group command follows the same logic as the Design commands on the Design tab. It only auto designs members that have the Autodesign property set as checked (including other elements in the same group). This is to ensure that work already undertaken in rationalizing the section sizes and optimizations in stud spacings, web openings etc. are not undone by accident.

Once the Design plane, sub structure, members or group command is completed the Autodesign property is set in accordance with the Design tab > Options > Autodesign page.

Note. In the screenshot above the option is greyed out. This is because no elements on the chosen plane have the Autodesign property currently set as checked (on).

Note. For further details on groups refer to the linked Help article here.

2b. Design Selection command

After manually selecting some members in the active scene view, the Design Selection command can be performed by right clicking one of the selected members and choosing Design Selection from the context menu.

 

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This is simply a different way of selecting a sub-set of members and the design procedure is identical to that described in 2a above.

3. Design Member command

The Design Member command is accessible by right clicking a member and choosing Design Member from the context menu.

 

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The design is based on the analysis results from a previously run analysis/design. Hence, a design via the design tab or an Analysis via the Analyse tab is required beforehand, so that design forces exist.

The command works differently to the design methods discussed above. The Design member command will always be auto designed using the specified design section order file (including other elements in the same group) irrespective of the Autodesign property value.

Care is therefore required, so that you do not unintentionally undo any optimizations already performed.