Lines between 3D points?

[JimR]

I have a TPoint3DSeries and I would like to draw lines between various pairs of points (not just connect them in sequence). What is the best (simplest) way? For 2D I used TArrowSeries and that worked well. Is there a 3D equivalent?

Thanks, Jim

[Yeray]

Hello,

You could use a second TPoint3DSeries with hidden Pointers and copy points from a series to the other.
In this example, I'm calling this second series "Links":

Code: Select all

uses TeePoin3;

var Series1, Links: TPoint3DSeries;

procedure TForm1.FormCreate(Sender: TObject);

  procedure AddLink(ValueIndex1, ValueIndex2: Integer);
  begin
    Links.AddXYZ(Series1.XValue[ValueIndex1], Series1.YValue[ValueIndex1], Series1.ZValue[ValueIndex1]);
    Links.AddXYZ(Series1.XValue[ValueIndex2], Series1.YValue[ValueIndex2], Series1.ZValue[ValueIndex2]);
    Links.AddNull(0);
  end;

begin
  Series1:=Chart1.AddSeries(TPoint3DSeries) as TPoint3DSeries;
  Series1.FillSampleValues;
  Series1.LinePen.Visible:=False;

  Links:=Chart1.AddSeries(TPoint3DSeries) as TPoint3DSeries;
  Links.Pointer.Visible:=False;

  AddLink(2,6);
  AddLink(2,10);
end;

[JimR]

So I would then have a new series for each line segment I need to draw? It would work but a generalization of TArrowSeries to 3D would be much more elegant and would make 3D just a generalization of 2D.

[Yeray]

Hello Jim,

If you look at the sample code I posted, you'll see I'm adding 3 points for each segment into the same series. Two of these points are the origin and destination points for the line to be drawn, and the third point is a null point, so the next time we add a line segment, we aren't connecting them.

[JimR]

Oh, I did not notice that. Not elegant but should work. Thanks.

[JimR]

I tried that and it works except for one odd problem. If there is a line segment connecting the last point to some other point then when I rotate the chart with the mouse in some views a line suddenly appears connecting the last point to the first point. If no line connects the last point then this does not seem to happen. I know that you would like a small demo of the problem but this is all withing the large program I am working on that generates the data to be plotted.

[JimR]

Oh, I just discovered that the 3D vector series I needed actually does exist. The TVector3DSeries series is in the VCLTee.TeeSurfa unit. Now the problem is that some lines display too light (see the screenshot). Perhaps they are drawn but much too light.

Screen Shot 03-23-17 at 08.20 AM.PNG (24.79 KiB) Viewed 13584 times

[Yeray]

Hello,

I tried that and it works except for one odd problem. If there is a line segment connecting the last point to some other point then when I rotate the chart with the mouse in some views a line suddenly appears connecting the last point to the first point. If no line connects the last point then this does not seem to happen. I know that you would like a small demo of the problem but this is all withing the large program I am working on that generates the data to be plotted.

I see the problem is the lines in the Point3DSeries doesn't respect the null points. I've added it to the public tracker:
http://bugs.teechart.net/show_bug.cgi?id=1822

Oh, I just discovered that the 3D vector series I needed actually does exist. The TVector3DSeries series is in the VCLTee.TeeSurfa unit.

Right, sorry. You can use the TVector3DSeries as follows:

Code: Select all

uses TeePoin3, TeeSurfa;

var Series1: TPoint3DSeries;
    Vector: TVector3DSeries;

procedure TForm1.FormCreate(Sender: TObject);

  procedure AddVector(ValueIndex1, ValueIndex2: Integer);
  begin
    Vector.AddVector(Series1.XValue[ValueIndex1], Series1.YValue[ValueIndex1], Series1.ZValue[ValueIndex1],
                     Series1.XValue[ValueIndex2], Series1.YValue[ValueIndex2], Series1.ZValue[ValueIndex2]);
  end;

begin
  Series1:=Chart1.AddSeries(TPoint3DSeries) as TPoint3DSeries;
  Series1.FillSampleValues(5);
  Series1.LinePen.Visible:=False;
  Series1.Marks.Visible:=True;
  Series1.Marks.Style:=smsPointIndex;

  Vector:=Chart1.AddSeries(TVector3DSeries) as TVector3DSeries;
  Vector.UseColorRange:=False;
  Vector.Color:=clBlack;

  AddVector(2,4);
  AddVector(1,3);
  AddVector(3, Series1.Count-1);
end;

Now the problem is that some lines display too light (see the screenshot). Perhaps they are drawn but much too light.

You only have to disable UseColorRange as shown above

[JimR]

OK, this solves that problem - thanks.