For those of you who are unfamiliar with SPACE GASS, this page gives some basic instructions on how to quickly input and edit a structural model. It also contains various hints and techniques that will help to get you started.

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It is recommended that you print this document and use it as a quick reference when running SPACE GASS for the first few times.

• Before you begin experimenting with the features described here, you will need to have a structural model loaded into SPACE GASS. You can do this by either:
  
  
  • Opening an existing job - Select "Open" from the "File" menu or press the button and then choose one of the sample jobs supplied with SPACE GASS.
    
    
  • Creating a new job - The easiest way is to use the "Structure Wizard" to quickly create a standard structure to your specifications. Select "Structure Wizard" from the "Structure" menu or press the button, select a structure type and then enter your data into the form that appears next.

  After opening or creating a job, it will be displayed graphically.
  
  

• Use the wheel on your mouse to experiment with zooming, panning, changing the viewpoint or changing the diagram scales for the model you currently have displayed. If you don't have a mousewheel, you can use the keyboard arrow keys instead.
  
  

  Operation Zoom in Zoom out Zoom full Zoom previous Pan down Pan up Pan left Pan right Rotate down Rotate up Rotate left Rotate right Enlarge load diagram Reduce load diagram Enlarge deflection diagram Reduce deflection diagram Enlarge moment diagram Reduce moment diagram Enlarge shear force diagram Reduce shear force diagram Enlarge axial force diagram Reduce axial force diagram Enlarge torsion diagram Reduce torsion diagram Enlarge buckling diagram Reduce buckling diagram Enlarge stress diagrams Reduce stress diagrams

  Keyboard shortcut Up arrow Down arrow Right arrow Left arrow Ctrl+Up arrow Ctrl+Down arrow Ctrl+Right arrow Ctrl+Left arrow Shift+Up arrow Shift+Down arrow Shift+Right arrow Shift+Left arrow L+Up arrow L+Down arrow D+Up arrow D+Down arrow M+Up arrow M+Down arrow S+Up arrow S+Down arrow A+Up arrow A+Down arrow T+Up arrow T+Down arrow B+Up arrow B+Down arrow E+Up arrow E+Down arrow

  Mouse shortcut Mousewheel forwards Mousewheel backwards Ctrl+Mousewheel forwards Ctrl+Mousewheel backwards Shift+Mousewheel forwards Shift+Mousewheel backwards V+Mousewheel forwards V+Mousewheel backwards H+Mousewheel forwards H+Mousewheel backwards L+Mousewheel forwards L+Mousewheel backwards D+Mousewheel forwards D+Mousewheel backwards M+Mousewheel forwards M+Mousewheel backwards S+Mousewheel forwards S+Mousewheel backwards A+Mousewheel forwards A+Mousewheel backwards T+Mousewheel forwards T+Mousewheel backwards B+Mousewheel forwards B+Mousewheel backwards E+Mousewheel forwards E+Mousewheel backwards

  
  
• Experiment with the following toolbar buttons to change the way the model is displayed or to turn labelling, annotation or analysis result diagrams on or off.
  
  

  	Redraw the model
  	Display node restraints
  	Display labelling and annotation (ie. node numbers, diagram values, etc)
  	Display load diagrams
  	Display bending moment diagrams (if analysed)
  	Display shear force diagrams (if analysed)
  	Change the scale of the model or any of its superimposed diagrams

  
  
• If you have any load or analysis result diagrams turned on, you can select the load cases that are displayed by selecting from the load cases combo box on the top toolbar. Click on the button to the right of the combo box to copy, renumber or delete entire load cases.
  
  
  
  
• View or edit the data for each part of the model in a spreadsheet format by using the program's datasheets. Click on the toolbar button to access the datasheets.
  
  
  
  

  Editing data	Move to the desired cell using the keyboard arrow keys (recommended) or mouse and then type in or select the desired data.
  Combo boxes	To edit combo box cells, either click on the arrow and then make your selection or just use the keyboard arrow keys to move to the combo box cell and then type the first character of the desired selection. For example, to change a Yes/No combo box to Yes, just move to the cell and then type Y.
  Adding data	Move to the bottom (blank) row and then type in the new data.
  Sorting	Click on the column heading to sort on. Further clicks cause the sorting to alternate between ascending and descending order.
  Selecting rows	Click on the button to the left of the row to be selected. You can select multiple rows by by: 1. Dragging up or down on the selection buttons. 2. Selecting one row, holding down the CTRL key and then selecting additional rows. 3. Selecting one row, holding down the SHIFT key and then clicking on another selection button to select all the rows in between. 4. Alternatively, you can click on the blank button at the top-left corner of the datasheet to select all the rows.
  Split screen	Move to the small black bar just to the left of the horizontal scroll arrow and then click and drag it to the right to introduce and position a vertical split screen division. Drag it back to its original position to remove it.
  Multi-row editing	Possibly one of the most useful datasheet editing features! It allows you to edit multiple rows of data simultaneously. The procedure is as follows: 1. Select the rows to be edited by clicking on the buttons at the left end of the rows, using the CTRL or SHIFT keys to highlight multiple rows (see "Selecting rows" above). 2. Move in any highlighted row to the column you want to edit. 3. Click the right mouse button. 4. Enter your data and click on the Ok button. 5. All the highlighted rows will be updated. 6. Go back to step 2 above to edit another column.

  
  
  
• Edit multiple datasheet rows simultaneously by typing into just one field (see multi-row editing above).
  
  
  
  
  
• Double-click on a node or member to query or edit its properties via the properties forms shown below.
  
  
  
  Depress the button to get access to master-slave constraints.
  
  
  
  Depress the button to get access to section properties.
  Depress the button to get access to material properties.
  Depress the button to get access to member offsets.
  
  You can change the properties of a node or member by typing into any of the editable fields in the properties form. The new properties will take effect as soon as you close the form.
  
  
• While the node or member properties form is open, simply click on another node or member to have its properties displayed in the form. Close the form when you are finished.
  
  
• From the node or member properties form, click on the “Results” button to display a full set of analysis results for the selected node or member. You can then click on any other nodes or members to bring up their analysis results.
  
  
  
  
  
• Graphically edit your model or apply some loads to it. There are a number of alternative methods you can use to edit your model graphically, however the one we recommend is as follows:
  
  1. Select the nodes or members to be edited,
  2. Click the right mouse button,
  3. Choose an operation from the floating menu that appears,
  4. Follow the prompts to complete the operation.
  
  When selecting nodes or members, you can select individual nodes or members by clicking directly on them. Alternatively, you can select groups of nodes or members by placing a window around them. Nodes or members can be de-selected by simply selecting them again.
  
  When selecting using a window, just click the left mouse button at one corner of the window, move the mouse to the opposite corner and then click again. Don't hold the mouse button down while moving to the opposite corner.
  
  
  • A "normal" selection window (that has its second corner to the right of the first corner) selects all the members that fall completely within the window. A normal selection window is drawn with a solid line.
    
    
  • A "crossing" selection window (that has its second corner to the left of the first corner) selects all the members that fall completely within or cross the window. A crossing selection window is drawn with a broken line.
    
    
    
    

  After selecting the desired nodes or members, click the right mouse button to choose an operation from the floating menu that appears. Follow the prompts to complete the operation.
  
  
  
  
  

• Check or change the units being used in your model by selecting "Units" from the "Structure" menu. Note that you can mix and match different units for different parts of the structural data. If you change any of the units, the structural data can be converted automatically.
  
  
  
  
  
• Graphically view, edit or input some loads by selecting some members, clicking the right mouse button and then choosing "Member distributed forces" from the floating menu that appears.
  
  
  
  In the load case form that appears next (see above), if you are inputting new loads then you would probably leave the load cases list field blank and specify the load cases in the datasheet that follows. If you are editing loads then you may also wish to leave the load cases list field blank unless there are a large number of load cases and you want to restrict the datasheet to just some of them.
  
  You should then choose between showing the loads applied to each selected member individually (ie. one line of data for each member) or applied as a group to all the selected members (ie. one line of data for all the members). The advantage of the "group" selection is that you only have to input one line of data in the datasheet to have it applied to all the selected members. This can be particularly useful if you are applying the same load to a number of members. If you are inputting a different load on each member then you should choose the "individual" selection. Choosing "individual" can also be useful if you are simply trying to see what loads are already applied to the members you have selected.
  
  If you have elected to show the loads applied to each member individually then you can also choose between showing all the selected members or just the ones that are loaded. If you are inputting new loads then you would probably choose to show all the selected members, whereas if you are editing existing loads or just viewing loads then showing just the loaded members may be preferable.
  
  
  
  A datasheet then appears with any existing loads shown. You can add, edit or delete loads and then click on the Ok button to save any changes.
  
  
• You can easily add new members to the model by simply drawing them. Click on the toolbar button to initiate the draw feature. To draw a new member, move to its start point, click the left mouse button, move to its end point and click the left mouse button again. Continue to move and click to draw additional new members. To disconnect from the previously drawn member, click the right mouse button. To exit from the draw feature, click the right mouse button again.
  
  You can draw new members that are attached to existing members by simply ensuring that the circle attached to the cursor touches an existing node or member when you click the left mouse button. The point at which the new member attaches to the existing member depends on the "Attach" setting displayed on the attach button (see further information below).
  
  You can use the buttons along the bottom of the graphics area to assist you in inputting or editing your structural model graphically.
  
  
  
  
  • Grid - Press this button to display a grid of reference dots at any desired spacing. This is a useful visual reference when you are drawing, moving or otherwise navigating around the graphics area.
    
    
  • Snap - Press this button to force the graphics cursor to snap to a grid of any desired spacing. This makes it easy to position points accurately. Note that Snap is only active during some operations such as drawing, moving, copying, etc.
    
    
  • Ortho - Press this button to force any lines being drawn to be either horizontal or vertical.
    
    
  • Attach - Press this button to choose how to attach new nodes or members to your structural model. Depending on the Attach setting, you can accurately attach new members being drawn to existing nodes or members (at their ends or at specified intermediate points).
    
    
    
    
  • Plane - Press this button to change the drawing plane. This makes it easy for you to create 3D models by working in or parallel to one plane at a time.
    
    
  • Coords - Press this button to toggle between the four coordinate systems. You can choose between Cartesian-absolute, Cartesian-relative, Polar-absolute or Polar-relative. As you move the cursor around the graphics area (when a graphics command is active) you can see the coordinates displayed in the chosen coordinate system at the bottom-right corner of the SPACE GASS window.
    
    
• If you can't accurately draw a line or position a point at the desired location, you can simply type in its coordinates at the keyboard. Just begin typing and the input form shown below will appear automatically. You can use Cartesian-absolute (eg. 3.9,2.37), Cartesian-relative (eg. @3.9,2.37), Polar-absolute (eg. 12.34<45) or Polar-relative (eg. @12.34<45).
  
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• For complicated models, you may want to filter out some of the members so that you can work on just a small part of the model. One way to do this is to graphically select the nodes or members you want in the filter, click the right mouse button, choose "Create filter" from the floating menu that appears, select a filter number and then type in a name that you wish to use to refer to it.
  
  
  
  The model is then redrawn with the members not in the filter shown grayed out as shown below.
  
  
  
  
  You can also define filters in terms of node or member attributes, coordinates, etc. by clicking on the toolbar button and then specifying the required data in the filters form shown below.
  
  
  
  Once you have defined some filters, you can display any one of them by selecting from the filters combo box on the top toolbar.
  
  
  
  
  
• Click on the toolbar button to quickly find and select nodes or members based on criteria that you type in. Once the desired items are selected you can click the right mouse button to choose an action (the same as you would if you had selected the items by clicking on them instead of using "Find").
  
  
  
  
• The "Shape Builder" lets you build any shape by combining one or more sub-shapes. Shapes can be imported from a section library, calculated from standard shapes, or obtained from a set of boundary coordinates. You can get to the shape builder from the member properties form by clicking on the button.
  
  
  
  
  
• You can renumber individual or groups of nodes and members at any time. Any data that references node or member numbering (such as restraints, constraints, loads, etc.) is automatically adjusted by SPACE GASS.
  
  
  
  
  
• The orientation of a member relative to its own longitudinal axis (its angle of roll) can be specified in one of three ways.
  
  
  • Direction angle - specifies the angle between the member's local xy-plane and the vertical plane in which the member lies.
    
    
  • Direction node - specifies a node that the member's local xy-plane passes through.
    
    
  • Direction axis - specifies a global axis that the member's local xy-plane is aligned with.

  
  
  For example, all the columns around the perimeter of a circular rotunda (see above) could be made to have their webs aligned with the centre of the rotunda by use of a direction node. The direction node specified for all the columns could be positioned anywhere on a vertical axis passing through the centre of the rotunda. Note that a normal node or a dummy node (a node not connected to any members) can be used as a direction node.
  
  The direction angle, node or axis can be specified in the member properties form.
  
  

• In order to get a realistic look at your structural model you can generate a 3D view showing the full member geometry with hidden lines removed by clicking on the button.
  
  
  
  
  
• Member offsets allow you to specify an offset between the end of a member and the node to which the end is connected. They can be useful for modelling situations in which a number of members are connected to a common node but the member centrelines do not meet at the node. For example, member offsets could be used to model the case of two members of different depths connected end-to-end with the top flanges aligned.
  
  
  
  The member offset data can be specified in the member properties form.
  
  
  

This is just a small subset of the features in SPACE GASS. You should be able to find and use the other features by exploring the program's toolbars and menus. Don't forget that the entire user manual is contained within the help system which you can access from the Help menu or by pressing the Help button from anywhere within SPACE GASS.