# Modify Truss System Grid

* Select a truss system grid
* Select **Modify Truss System Grid** directly from **Truss+** menu

![](/files/lQGRydu3IraYl1vPc1WW)

* If there is a lock symbol near the value of parameter, it means that the truss system grid is attached to the roof (after updating grid from the roof, parameters will be updated automatically, depending on roof geometry)
* After choosing the command Update from roof, parameters with the lock symbol will be updated automatically, depending to the roof geometry
* **First girder ply** parameter describes how many girders will be placed in the first girder place

![](/files/WWXCOnuHduRn0b94LUVv)

* **Second girder ply** parameter describes how many girders will be placed in the last girder place

![](/files/mhIXXNTnUxpDO6vbs5rI)

**Important parameters:**

* Truss spacing
* Position of “L” return roof ridges
* Setback - to change setback value you need to create another type of truss system grid• Valley distribution parameters and others

![](/files/kgGmK52pUTjWkDNnAtT4)

**Example**

![](/files/qS7irvaI6TOVI6eC4WLc)

![](/files/IOIImYZQB1PIU8KgNFuD)

**Modify parameters for end rafters and jacks**

* Select a truss system grid
* Choose **Modify Truss System Grid** directly from **Truss+** menu

![](/files/f1aEjrbwqgOmpjOqhbhu)

* To set corner and end rafters or jacks parameters, choose **Jack configuration**

![](/files/bxbTxYvzogodlZKR0YZ7)

**Jack Configuration:**

* Lsr – a distance from the wall surface to the corner side rafter. Commonly Lsr=Ler
* Lsj – a distance from the wall surface to the side jack. This parameter can be calculated or user-defined. CommonlyLsj=Lej
* Corner rafters – if this check box is ticked, corner rafters will be generated
* End jack trusses begin from number – describes from which element are generated end jack trusses, instead of rafters
* Side jack trusses begin from number – describes from which element are generated side jack trusses, instead of rafters
* Side jacks (bottom chord) connected to – describes to which end jack are connected side jacks bottom chords

![](/files/oZbazGAfEu5Lru1cPtBE)

![](/files/JuGbxrw9CF93vThWajru)

**Parameters for defining setback and other valley parameters**

* Select a truss system grid
* Choose **Modify Truss System Grid** directly from **Truss+** menu

![](/files/qbP1NLNx9PprhQ0YZJZ6)

![](/files/6i3KmGLGmEMP6HZdeic8)

![](/files/CnEkvHccN7HlPEOD1u2H)

* If Valley Set Grid needs to be inserted, switch Off the Valley trusses will not be used check box

![](/files/cEOLU1W9ChUzyTSyE7Pl)

* **Valley pitch** If there is a lock symbol near the value of parameter, it means that the truss system grid is attached to the roof (after updating grid from the roof, parameters will be updated automatically according to the roof geometry)

![](/files/wFKtvrHb0iAG9af5F6J2)

* **Valley placement**: spacing is calculated from the bottom • **Valley placement**: spacing is calculated from the top

![](/files/Sq6fbfvIAWMq2vA2sapy)![](/files/ejJ0DuLJDzRS0uaMehf7)

* **Cut bottom chord of Valley**

![](/files/AGDnXIQ1qRZazPodrTVQ)![](/files/kPlDY7thhI32f9THJKXc)

![](/files/cMbVJr1IYN8pitCX8eZw)

![](/files/yj9BR60iW6owKFUEEGaP)


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