Understanding The Splines In Solidworks

A spline is a continuous curve that passes through discrete points specified by the user. It is a curve that is defined by its continuously changing curvature to create an organic shape which is not otherwise possible with lines and arcs. Generally, splines in Solidworks can be created by using two endpoints or even multiple endpoints. The splines are used to create a profile that is complex in shape. Points are placed to shape the curve. Unlike standard geometry, it is common to leave splines under defined in sketches. It can be complex to constrain the curve whilst maintaining a smooth, free-flowing shape.

 

Types of Splines in SolidWorks:

The SOLIDWORKS software supports two types of splines, B-splines and style splines.

 

B-SPLINES

Known as base-splines, B-splines are used to create complex curves. You can define and modify them using several controls, including spline points, spline handles, and control polygons. A single B-spline can have multiple through points and spans (the region between through points). You can apply curvature constraints at each endpoint. At each point, you can weigh the tangency vector and control the tangency direction.

 

 

Steps To Create A Multipoint B-Spline

 

To create multiple point splines:

 

1, Click Spline (Sketch toolbar) or Tools > Sketch Entities > Spline.           
The pointer changes to.

 

 

2, Click to place the first point and drag out the first segment.

3, Click the next point and drag out the second segment.

4, Repeat for each segment, then double-click when the spline is complete. The Spline PropertyManager appears. The spline handles display by default. To hide or display spline handles, click Show Spline Handles (Spline Tools toolbar) or Tools > Spline Tools > Show Spline Handles.

 

 

The Insert Spline Point command adds one or more points to splines.

With spline points, you can:

• Use spline points as handles to pull the spline into the shape you want.
• Add dimensions between spline points or between spline points and other entities.
• Add relations to spline points.
  

To insert spline points:

1, In Edit Sketch mode, right-click a spline and select Insert Spline Point, or click Insert Spline Point (Spline Tools toolbar).

 

 

 

The pointer changes to . If the pointer is not on the spline, the pointer changes to .

 

2, Click one or more places on the spline where you want to insert a point.

 

  

 

What Is A Spline Handle In Spline?

 

 

Spline handles allow you to manipulate the geometry of each point you placed. There are three parts to the spline handle:

1. The diamond shape allows you to change the angular direction through a point.
2. The arrow allows you to modify the tangent magnitude or weight of the handle.
3. The point on the end allows you to modify both at the same time.
   

After you have moved one of the handles it will go from grey to blue, indicating it was activated and moved. De-selecting the spline causes the grey handles to disappear, but the blue ones remain visible.

 

 

 

What Are Control Polygons In Spline? 

You can control the shape of a 2D or a 3D spline by dragging or setting values for the control polygon nodes. Changing the locations of the control points (nodes) updates the values of the X and Y Coordinates (in 2D splines), and X, Y, and Z Coordinates (in 3D splines) in the PropertyManager.

 

To open the Spline Polygon PropertyManager:

• Select a control point and make it active.
• You can drag the control points or adjust the values in the PropertyManager

 

                       

 

The select point on control polygon active

 

Style Spline

Style splines, based on Bézier curves, are a good option when it is important to have a smooth curve (that is, to assure curvature continuity). You define and control the curves using control vertices. The control vertices form a control polygon or hull of the curve. There are no through points, so a style spline has only one span between the endpoints. You can infer style splines for tangency or equal curvature. You can constrain the points and dimension the curves' sides. These curves also support mirroring and self-symmetry.

 

 

What Are Control Vertices In Spline?

Splines are defined either with fit points or with control vertices. By default, fit points coincide with the spline, while control vertices define a control frame. Control frames provide a convenient method to shape the spline. Each method has its advantages.

 

 

 

How To Edit A Control Vertex or Control Vertices Locally In Graphics View Area?

Local edit allows you to drag and manipulate the shape of a style spline without affecting adjacent style splines. This setting is helpful when you are working with multiple style splines that are connected but not fully constrained.

To modify a style spline using Local edit:

 

1, In an open sketch, select the style spline you wish to edit locally only.

 

 

 

Local edit only works with two or more style splines. The Style Spline PropertyManager displays.

2, In the Style Spline PropertyManager, under Options, select Local edit

3, In the graphics area, select and drag a control vertex. You can manipulate the shape of the control polygon without affecting the shape of the other style spline that it is attached to.

4, Click OK.