Drawing in 3D Space Derived Classes

ROOT
1

Hi,

I am attempting to create a derived class from TEllipse that will allow me to draw ellipses embedded in 3D space. I am unsure about the best way to accomplish this. I am assuming I need to define a paint method in my derived class. However,I am not 100% clear what the best approach is for the paint method. I have looked at paint for TEllipse, which makes calls to TPad methods. I also looked at the TPolyLine3D class. Could you give me some guidance on the best way to accomplish what I want.

Thanks.

Jon

2

It all depends what you want to do. What do you mean by an ellipse in 3d ? a 2D ellipse in a plane or a 3d ellipsoid ?

3

Hi,
I want to draw a series of 2D ellipses in a plane at various points in 3d space (not an ellipsoid). Thanks

Jon

4

May you can get inspiration from the following macro. You will have to use TPolyLine3D to build your ellipses.

{
   c1 = new TCanvas("c1","PolyLine3D & PolyMarker3D Window",200,10,500,500);

   // Creating a view
   TView3D *view = TView::CreateView(1);
   view->SetRange(5,5,5,25,25,25);
   view->ShowAxis();

   // Create a first PolyLine3D
   TPolyLine3D *pl3d1 = new TPolyLine3D(5);
   pl3d1->SetPoint(0, 10, 10, 10);
   pl3d1->SetPoint(1, 15, 15, 10);
   pl3d1->SetPoint(2, 20, 15, 15);
   pl3d1->SetPoint(3, 20, 20, 20);
   pl3d1->SetPoint(4, 10, 10, 20);

   // Create a first PolyMarker3D
   TPolyMarker3D *pm3d1 = new TPolyMarker3D(12);
   pm3d1->SetPoint(0, 10, 10, 10);
   pm3d1->SetPoint(1, 11, 15, 11);
   pm3d1->SetPoint(2, 12, 15, 9);
   pm3d1->SetPoint(3, 13, 17, 20);
   pm3d1->SetPoint(4, 14, 16, 15);
   pm3d1->SetPoint(5, 15, 20, 15);
   pm3d1->SetPoint(6, 16, 18, 10);
   pm3d1->SetPoint(7, 17, 15, 10);
   pm3d1->SetPoint(8, 18, 22, 15);
   pm3d1->SetPoint(9, 19, 28, 25);
   pm3d1->SetPoint(10, 20, 12, 15);
   pm3d1->SetPoint(11, 21, 12, 15);
   pm3d1->SetMarkerSize(2);
   pm3d1->SetMarkerColor(4);
   pm3d1->SetMarkerStyle(2);

   // Draw
   pl3d1->Draw();
   pm3d1->Draw();
}
5

Yes. I was considering this type of thing. I am assuming I should place this in a paint virtual method for my derived class? Or should I make direct calls to tpad::polyline3d method, which I see in a lot of the root code. Which approach is better and why?

6

I think the best would be to make a TEllipse3D class based on the TPolyLine3D model.

7

Hi,

Ok. I have the 3D Ellipses drawing correctly as per the screenshot I attach. I derived a class from TEllipse instead of deriving from TPolyLine3D. Do you see an issue with that?

However, the main issue now is how do I fill these ellipses? They are TPolyLine3D objects. Is there a way to fill those?

Thanks.

-Jon
Ellipses.pdf (70.7 KB)

8

You should also derive from TAttFill
You will need to draw filles polygons, note lines.