(swplot-arrow)=

# swplot.arrow

## Syntax
  
`hPatch = swplot.arrow(rStart, rEnd, R, alpha, lHead)`
 
`hPatch = swplot.arrow(rStart, rEnd, R, alpha, lHead, nPatch)`
  
`hPatch = swplot.arrow(handle, ...)`
 
## Description
  
`hPatch = swplot.arrow(rStart, rEnd, R, alpha, lHead)` draws 3D arrows
between a given start and end position. The arrows will be a triangulated
[patch](https://www.mathworks.com/help/matlab/ref/patch.html) object.
   
`hPatch = swplot.arrow(rStart, rEnd, R, alpha, lHead, nPatch)` creates 
arrows with $5 n_{patch}$ number of patch faces per arrow.
 
`hPatch = swplot.arrow(handle, ...)` adds the generated patch object to a
given axis if `handle` is an axis handle or adds the arrows to an
existing [patch](https://www.mathworks.com/help/matlab/ref/patch.html) object, if the given `handle` points to a patch
object.
   
## Examples
 
Draw a 100 random arrows in the $(\pm 1,\pm 1,\pm 1)$ cube:
 
```matlab
swplot.figure
N = 100
swplot.arrow(2*rand(3,N)-1,2*rand(3,N)-1,0.01,30,0.05)
swplot.zoom(40)
```
 
```{image} /_static/img/generated/swplot__1.png
:alt: swplot.zoom(40)
```
 
## Input Arguments
  
`handle`
: Handle of an axis or triangulated patch object. In case of patch
  object, the constructed faces will be added to the existing object.
  
`rStart`
: Coordinates of the arrow starting point, one vector per arrow in a
  matrix with dimensions of $[3\times n_{obj}]$.
  
`rEnd`
: Coordinates of the arrow end point, one vector per arrow in a
  matrix with dimensions of $[3\times n_{obj}]$.
  
`R`
: Radius of the arrow body, scalar.
  
`alpha`
: Angle of the head in degree.
  
`lHead`
: Length of the head.
  
`nPatch`
: Number of points on the circle of the body, default value is stored in
  `swpref.getpref('npatch')`. The final patch object will have
  $5n_{patch}$ number of faces and $3n_{patch}$ number of vertices.
  
## See Also
  
[swplot.cylinder](#swplot-cylinder)