Vertical Alignment and Invisiable Dot

Question

Trying to put all thick bordered items into a vertical alignment. How do I do this?

Also, I'm trying to get the empty dot, where the two lines combine into one, to go away so the edges are connected. They are denoted by the "i*" naming convention. Specifically for this, I want the two lines to merge back together then attach to the next item. I tried the concentrate = "true" and that did not work as expected. The lines basically did not merge back together.

digraph G {
  concentrate = "true";

  node[shape="box", style="rounded"];
  {
    start [penwidth = 2.0]; 
    end  [penwidth = 2.0];
  }
  
  // PROCESS
  node[shape="box"]; 
  {
    calc [label = "Calculate\nSelected\nValues", penwidth = 2.0]; 
    deployPara [label = "Deploy\nPatachute" ]; 
    bldMsg [label = "Build\nMessage"];
    sendMsg [label = "Transmit\nMessage"];
    sleepCycle [label = "Sleep\nCycle", penwidth=2];
  }
  
  // Decision
  node[shape="diamond", style=""]
  {
    decidePara [label = "Decide\nDeploy", penwidth=2];
    decideMsg [label = "Decide\nMessage", penwidth=2];
  }
  
  node[shape = point, width  = 0, height = 0]; 
  {
    iDeploy
    iMsg
  }

  start -> decidePara
  
  decidePara -> iDeploy [label = "No", arrowhead = "none"]

  decidePara -> deployPara [label = "Yes"]
  deployPara -> iDeploy [arrowhead = "none"]

  iDeploy -> decideMsg ;
  decideMsg -> iMsg [label = "No", arrowhead = "none"];
  decideMsg -> bldMsg [label = "Yes"];
  bldMsg -> sendMsg;
  sendMsg -> iMsg [arrowhead = "none"]

  iMsg -> sleepCycle
  
  sleepCycle -> end;

  {rank=same; decidePara deployPara}
  {rank=same; decideMsg bldMsg sendMsg}
}

Edit the image commenter sees is:

Answer 1

Changes:

• splines=false (assuming you want straight lines)
• gave all nodes needing alignment a group attribute (see https://graphviz.org/docs/attrs/group/)
• changed size of i* nodes to fill in the gap
• also used headclip & tailclip attributes (https://graphviz.org/docs/attrs/headclip/) to fill in the gap (not sure if needed)

digraph G {
  concentrate = "true";
  splines=false

  node[shape="box", style="rounded"];
  {
    start [penwidth = 2.0 group=S]; 
    end  [penwidth = 2.0 group=S];
  }
  
  // PROCESS
  node[shape="box"]; 
  {
    calc [label = "Calculate\nSelected\nValues", penwidth = 2.0]; 
    deployPara [label = "Deploy\nPatachute" ]; 
    bldMsg [label = "Build\nMessage"];
    sendMsg [label = "Transmit\nMessage"];
    sleepCycle [label = "Sleep\nCycle", penwidth=2 group=S];
  }
  
  // Decision
  node[shape="diamond", style=""]
  {
    decidePara [label = "Decide\nDeploy", penwidth=2 group=S];
    decideMsg [label = "Decide\nMessage", penwidth=2 group=S];
  }
  
  node[shape = point, width  = .01, height = .01 group=S]; 
  {
    iDeploy 
    iMsg
  }

  start -> decidePara
  
  decidePara -> iDeploy [label = "No", arrowhead = "none" headclip=false]

  decidePara -> deployPara [label = "Yes"]
  deployPara -> iDeploy [arrowhead = "none" headclip=false]

  iDeploy -> decideMsg [tailclip=false]
  decideMsg -> iMsg [label = "No", arrowhead = "none" headclip=false];
  decideMsg -> bldMsg [label = "Yes"];
  bldMsg -> sendMsg;
  sendMsg -> iMsg [arrowhead = "none"]

  iMsg -> sleepCycle  [tailclip=false]
  
  sleepCycle -> end;

  {rank=same; decidePara deployPara}
  {rank=same; decideMsg bldMsg sendMsg}
}

Giving: