Draw a 3D tetrahedron

Hi

I'm new to Matlab.

how do I draw a tetrahedron?

The 4 corner points are given.

p1(0 0 0)

p2(0 1 1)

p3(1 0 1)

p4(1 1 0)

can anyone help?

[Rik]

Do you want a solid? A wire-frame? The dots only? What have you tried? I would say the first step is to store those corners in an array so your code can actually use it.

Have you done a basic Matlab tutorial, like Onramp?

[Adam Roudi]

i have tried to draw the points with plot3.

x = [0 0 1 1 0 1 0 1]
y = [0 1 0 1 0 0 1 1]
z = [0 1 1 0 0 1 1 0]

plot3(x,y,z)

other ideas?

[Rik]

If you only want the points:

x = [0 0 1 1 0 1 0 1];
y = [0 1 0 1 0 0 1 1];
z = [0 1 1 0 0 1 1 0];

plot3(x,y,z,'*')
axis([-0.5 1.5 -0.5 1.5 -0.5 1.5])

[Bjorn Gustavsson]

You can spice up Rik's idea by using the scatter3 function:

scatter3(x(1:4),y(1:4),z(1:4),34,1:4,'filled'),colorbar

That way you get the points coloured in order.

Then if you want to plot the triangular surfaces you can use fill3 to do that, for example the triangle with the three first points in the corners:

fill3(x(1:3),y(1:3),z(1:3),'r')

Then you'll have to do the same for the remaining triangles.

HTH

Answer 1

[Bjorn Gustavsson]

Have a look at the help and documentation of plot3. That function should give you what you need. The tedious thing you need to take into account when plotting the exges of a solid is that you need to make sure to plot each edge. This should get you started:

p1 = [0 0 0];
p2 = [0 1 1];
plot3([p1(1),p2(1)],[p1(2),p2(2)],[p1(3),p2(3)],'r.-')
hold on

HTH