Defining a New Truss

Before inserting a truss, there must have supports created for truss.

To define a Truss:

1. Click on "Truss"  button in "Modelling" ribbon or use command line at right bottom corner.                                                                                                                                   
   
2. Pick a grid intersection to define the start end of the truss (in the 2D or 3D view). A dynamic rubberband will appear with the default truss type if no truss is defined before. 
   
   
   
3. Pick another grid intersection to define the end of the truss. After the second point is picked, the truss dialog will appear.

1. There are three sub-menus under Truss Generator dialog which are General, Splices and Members. 

1. One of the listed truss types and patterns can be selected.
   
2. User defined trusses can be modeled. You can save, user defined trussese to use in other projects.
   
3. Once you selected the truss type, you can edit the geometry of trusses in "Geometry" section.
   

            

1. Truss Support Placement: Support placement (green icon) is the insertion point of the truss. It determines the height level of the truss, with either the bottom or top chord aligned with the storey height. Green icons in the view stands for column top points. In case of bottom chord, trusses and columns connected at bottom chord. In case of top chord, truss will be inserted at side of column and both bottom and top chord will be connected to column. 
   

1. Left/Rigth Vertical Offset: Offset between column top point and truss placement point can be edited.
   
2. Invert Truss: Truss will be rototed by 180 degree. 
   
3. Divide Cross Diagonal Frames: X shaped diagonal members can be divided. 
   
4. Model Joints as Fixed: As default truss members modeled as pinned. You can change these joints as fixed connections. 
   
5. Apex Height
   
6. Enter Left/Right Eave Angle By Angle or Height: You can edit heel angles either by entering heigths or angles. 
   
7. Spans:  Spans can be edited seperately.
   
8. Delete First and Last Verticals : Deletes first and last verticals of the truss. If top chord is selected as truss support placement,  first and last verticals will be deleted automatically. 
   
9. Wire Frame: You can view 3D truss wire frame by this command. Second click on the command will close the view.
   
10. Shrinked: Connection points will be invisible. You can visualize divided members. 
    
11. Reset View: Resets all changes in 3D view. 

Truss Members can be exploded and converted into frame members. 

To explode a truss:

1) Select a single truss or multiple trusses.

2) Right-click and pick “Explode Selected Trusses”.

3)  Accept the warning message.

User Defined Trusses

Features of Custom Truss Generator are listed below: 

1. Undo/Redo:  (ShortCuts: CTRL+Z, CTRL+Y)
   
2. Top Chord: Insert top chord.
   
3. Bottom Chord: Inserts bottom chord.
   
4. Vertical: Inserts the vertical members in truss pattern. 
   
5. Diagonal: Inserts the diagonal members in truss pattern. 
   
6. Horizontal: Insert default member. If diagonal and vertical are not enough, horizontal member can be used. 
   
7. Clear All Frames: Clears all frames. 
   
8. Clear all Guidelines : Clears all Guidelines. In order to add new guide line click "+" button. "x" button deletes guideline. 
   
9. Crate Points Btw Two Points: Insert new points between two selected points by dividing equal parts. Pick two points and enter the number of new points. 
   
   
   
10. Divide Frame: Divides selected member into equal intervals. 
    
    
    
11. Add Extension Point: Adds extension point to line which is formed by two points. Select two points to specify line and enter the value. 
    
    
    
    
12. Measure Distance Between Two Points: Measures the distance between two points.
    
13. Stretch: Selected frame members can be stretch.  

            

1. You can use Delete button on keyboard to delete selected member.
   
2. Save to Library: User Defined Trusses can be saved. You can also add explanations about custom trusses.
   
   Truss library is at  C:\Users\UserName\Documents\ProtaLib\CustomTrusses . You can share custom trusses with other users. 
3. Load From Library: You can use one of the saved custom trusses. Also,you can edit custom truss for new span by using "Stretch Truss in X Direction Option".

Splices 

You can add splices top and bottom chord of the truss. Splice length can not be less than 1 cm. Due to visibility, you can add longer splices. 

Defining/Editing Members

Section properties of truss members can be edited under Members Menu. 

Truss members are grouped as "top chord", "bottom chord", "diagonal" and "verticals". Members sections can be changed multi or individually. 

Support conditions of both ends of members can be edited. If the member end condition is pinned, it will be shown with magenta sphere at preview. If the end condition is fixed, nothing will be shown. 

In order to delete members you can use "Delete" button at toolbar. 

"Reset Members" button will change all members to initial conditions. 

After all changes, press "OK" button. Copy mode will be activated automatically. You can insert edited truss into other columns with same span length. You can deactivate copy mode by pressing "Esc".

Copying/Moving an existing Truss

To Copy/Move an existing Truss:

1. Select the truss, right-click select Copy or Move command.
   
2. Select the base-point and click another point for your destination point. The COPY mode will continue until you press ESC or Right-Click.
   
3. You can deactivate copy/move mode by pressing "Esc".

Changing Truss Properties (Batch Mode)

You can change properties of more than one truss at the same time. The trusses must be same type. Select the trusses(multi selection) that properties will be changed. 

Changes in the properties will be applied all trusses. 

Please see the "Cutom Truss Editor Properties" video at the below link. 

Import From DXF

Colour in sample above are just illustrated for display purpose only, user do not need to change the colour in the CAD drawing in order to import. 

Steps:

1. Draw simple truss profile in DXF drawing using straight line only and ensure to check the units to be in metrics (ie. mm).
   (During import, the width will be shrunken /stretched depends on the truss width difference created in ProtaStructure. However height will be remained.)
   
2. In ProtaStructure select "Truss"  in Modelling tab and pick start point and end point of truss.
   
3. Select "Import From DXF" and select DXF of the truss.
   
4. Adjust the scale factor, dimension units of the drawing, start point and end point of the truss. Select "Import" after configuration.
   
5. In Truss Editor, user may require to define each members. Left click to select the member(s) and right click to define. Click "OK" after defining all the truss members.
   

Support of Truss

The "Green" support in the properties is actually the insertion point of the truss (refer its definition of the  "Truss Support Placement"  at the top of this article) only. 

The support of the truss will be automatically determined by the program when there is column/wall connected to truss.

This means that if user wish to model a cantilever truss, user can directly model a single column/wall to either side of the truss and check the behavior in Analytical Model (Example below).

Similarly, if user wish to model additional supports, user can directly model the column/wall supporting the truss and check the behavior in Analytical Model (Example below).

As a tip to do so, you may  select the column below the truss and  utilise the "Extend Column to Member" to ensure the correct analytical connectivity. Having said that, it is always a good practice to check the model behaviour in the analytical model.