3D plot gives empty figure

Hi all

I have 4 matrices of 4x4 size. I do

for n=1:size(P1,1)
    
    plot3(P1(n,2),P1(n,3),P1(n,4))
    hold on
    plot3(P2(n,2),P2(n,3),P2(n,4))
    hold on
    plot3(P3(n,2),P3(n,3),P3(n,4))
    hold on
    plot3(Pmid(n,2),Pmid(n,3),Pmid(n,4))
    hold on
    savefig('3Dplot.fig')
end 

but I get empty figure !!

Also , how can I parameterize the figure name, like if I have an str variable : filename and I need to save the figure as filename.fig ?

also I needed to call this code from another m file , writing the name like

plot3D

plot3D.m

'plot3D'

did not call the m file to run

[Adam]

If you are going to plot scalar points with plot3 you likely need to play around with MarkerType and MarkerSize, or whatever the properties are called, as detailed in

doc plot3

If you aren't intending to plot scalars you are doing something wrong with your plot instructions

[farzad]

Well I have scalars, but I think since they are few points I can't see them. When my matrices are so big I see the blue line of the plot clearly.

How do I use marker size then?

[farzad]

Or better if I could connect them with a line?