Context: When creating a structural grid from a solid or surface body, the
      grid includes:
        - The edges of the solid or surface body.
- The edges formed by the intersection on the faces of the solid or surface body and the
          planes formed by the extrusions of sketch lines.
When creating a structural grid from axis systems, the grid is displayed on the YZ
        plane of the selected axis system.
- 
        Before you begin, choose one of the following:
        
      
- In  the tree activate the shell and core of the building, or a story product.
           
- 
        
          From the 
        Building section, click Reference Plane Grid  . .
- 
        Select the sketch for the basis of the reference plane grid as follows:
        - In the Reference Planes Grid dialog box,  click Select Profile  . .
- 
            From the 3D area, click the sketch or lines that are to serve as the
              basis for the reference plane grid.
          
 
- Select the reference planes as follows:- In the dialog box, click Select Reference Plane.
- 
            In the tree, click each reference plane or each axis system on
              which you want the reference plane grid to display.
            In the  3D area, a preview of the reference plane grid on each
              selected reference plane is displayed. If you select an axis system, a preview of the
              reference plane grid on the YZ plane of each selected axis system is displayed.  
 
- 
        To use a solid or surface body as input, in the dialog box, click the Input
            Bodies box. In the tree, select the solid or surface bodies that are to serve
          as the basis for the reference plane grid.
      
- 
        To transform the grid, perform the following steps:
        
          - 
            Expand Scale and scale the grid.
            
               
                    
                      | Option | Description |  
                      | Using a law | 
                          Select the Use law for scale check box.From the tree, select a law. The system uses the law as a reference to scale the grid. |  
                      | Manually | 
                          In Scale start, enter the scale of the grid at
                            the bottom of the starting story.In Scale end, enter the scale of the top of the
                            uppermost story of the grid.Note:
			If you have entered a Roof
                                Thickness value, the Scale end
                              value determines the scale of the virtual roof. |  
 
- 
            Expand Twist and twist the grid.
            
               
                    
                      | Option | Description |  
                      | Using a law | 
                          Select the Use law for twist angle check
                            box.From the tree, select a law. The system uses the law to obtain twist angle values at each output grid
                            plane. |  
                      | Manually | 
                          In Twist start angle, enter the angle of the
                            grid at the starting story.In Twist end angle, enter the angle of the
                            uppermost story of the grid.
                               Note:
			If you have entered a Roof Thickness
                                value, the Twist end angle determines the
                                angle at the virtual roof. |  
 
- 
            Click the Select Spine box.
          
- 
            From the 3D area, select a spine.
            By default, the system uses the global z axis as the spine.
              While transforming the grid, the system scales and twists about the points where the
              spine intersects with the output grid planes. 
- 
            Select one of the following:
            
               
                    
                      | Option | Description |  
                      | Project to output planes | Projects the grid to angled planes without rotation. The
                        system aligns column points on angled planes to those on the top-story
                          plane. |  
                      | Rotate to output planes | Projects the grid to angled planes with rotation. The
                        system rotates the grid to match the inclination of angled planes. |  
 
 
- 
        
          Click 
         . .
 The reference plane grid appears on all the selected reference
      planes. 



In
      the tree, the system displays Reference Plane
        Grid in Shell and Core in the Structure
        Grids node.