Comments

• zli88

  March 2020

  It is beacuse my pattern has a background, I need to clear some certain parts in order to fit my structure in it. And it dose not help to just erase the background by hand in Editor mode.
• Matthias

  March 2020

  Hi,

  I think you misunderstood the meaning of "erase": it will take out a specific object from the object collection, not void the area under the shape.

  What you need is a "boolean NOT" operation. Or you need a selective delete. "NOT" is available within the DRC framework, but it will not preserve the hierarchy not labels of the original layer. A selective delete is a difficult operation if hierarchy is involved and shapes need to be deleted from subcells.

  I can't give advise without knowing more about the application you're planning.

  Matthias
• zli88

  March 2020 edited March 2020

  Hi Matthias

  This is my script. I have made the certain shape for the 'eraser' and the background. What I need to do is something like from image 1 to image 2.
  

  

  I think it is really difficult to use the 'boolean' operator for my case. It can be much easier if there is a function to customize the shape of 'erase' in Editor mode.

  script

  def block(layout, cell, layer, width, x0, y0,rad,x_r, y_r, width1, length, x1, y1, r):
  
      theta_start =0
      theta_end =360
      theta = np.linspace(theta_start, theta_end, 800)
      x = rad*np.cos(2*np.pi*theta/360)+(x_r);
      y = rad*np.sin(2*np.pi*theta/360)+ (y_r-width1/2);  
      a1=[]
      for i in range(len(theta)):
           a1.append(pya.Point(x[i], y[i]))
      wg_path1=pya.Path(a1,width1) 
  
      theta_start=0  #angle in degree
      theta_end = 90  #angle in degree
      theta = np.linspace(theta_start, theta_end, 200)
      x2 = r*np.cos(2*np.pi*theta/360)+(x1+length);
      y2 = r*np.sin(2*np.pi*theta/360)+ (y1-r+width1/2);
      a2 = []
      for i in range(len(theta)):
          a2.append(pya.Point(x2[i], y2[i]))   
      wg_path2 = pya.Path(a2, width1)    #turing waveguide
      theta_start=180
      theta_end = 270
      theta = np.linspace(theta_start, theta_end, 200)
      x = r*np.cos(2*np.pi*theta/360)+(x1+length+2*r);
      y = r*np.sin(2*np.pi*theta/360)+ (y1-r+width1/2);
      a3 = []
      for i in range(len(theta)):
          a3.append(pya.Point(x[i], y[i]))     
      wg_path3 = pya.Path(a3, width1) #turing waveguide
  
      wg_path4=pya.Box(x1, y1, x1+length, y1+width1)  #straight waveguide
  
      eraser=[wg_path1,wg_path2,wg_path3,wg_path4]    #the eraser is a combination of four parts
  
  
      for o in range(2):
       for u in range(18):
        for i in range(36):
         hull=pya.Box(x0+(2*i+o)*width, y0+(4*u-2*o)*width,x0+(2*i+1+o)*width, y0+(1+4*u-2*o)*width)
         cell.shapes(layer).insert(pya.Polygon(hull))  # background
  if  __name__ ==  "__main__" :
  
      layout = pya.Layout()
      top = layout.create_cell("TOP")
      l1 = layout.layer(1, 0)   
      y0_1=0
      x0_1=0
      x1_1=1000
      y1_1=1000
      width_1=10000
      width_2=10000
      length_1=800000
      r_1=40000
      rad_1=80000
      x_r1=length_1/2
      y_r1=rad_1+width_1+width_1+1000 
      block(layout=layout, cell=top, layer=l1, width=width_1,  x0=x0_1, y0=y0_1,rad=rad_1, x_r=x_r1, y_r=y_r1, width1=width_2, length=length_1, x1=x1_1, y1=y1_1, r=r_1)
      layout.write("D:/cmp_block.gds")
      print("Done.")
  

  Thank you
• Matthias

  March 2020

  Hi,

  Please format your code using Markdown formatting - put a line with a triple backtick before and after the code. The above form is not quite readable.

  I think boolean operations are basically the easiest way to implement your request. Your script is already producing a layout with the "erase" layer.

  You can then use a DRC script like this:

  # This will remove the "eraser" from layer 17, datatype 0 (example):
  eraser = layout("D:/cmp_block.gds")
  
  (input(17,0) - eraser.input(1, 0)).output(17, 0)
  

  If you care to write your script in Ruby you can basically integrate the eraser generation into the DRC script and skip the intermediate file step.

  Matthias
• zli88

  March 2020

  Hi Matthias,

  I finally find the function 'Region'. Just use pya.Region(A)-pya.Region(B), then it gives what I need. And this is what so called 'boolean'. Because I am a noob of coding, it really took me a while to understand how it goes.
  Anyway, thank you for being so helpful.

  Zhan
• Matthias

  March 2020

  Hi Zhan,

  very good ... that is actually even better. I did not dare to propose this, but this will allow you to implement the feature in a single piece of code.

  "Regions" are basically what is a "layer" on the canvas. The region object allows manipulating and analysing layers in manifold ways. It's a very mighty concept.

  I just would like to point out this:

  • Regions don't represent labels (text objects). Hence such objects will be lost.
  • Regions only know polygons. Paths will be converted into polygons if you use regions. Same for boxes.
  • Regions are flat. If you have a hierarchy of cells, the Regions will represent the flattened view (as looking from the top cell). Boolean operations will then give you the full layer, but the hierarchical composition is lost.

  Regards,

  Matthias