Plot 3D line object with alpha gradient

Dear all,

I have a 3D point set which I would like to plot as connected line segments. In addition, I would like the points (lines) furthest away (from the point of perspective) to appear more distant by having an alpha gradient, i.e points closer to the viewer should have higher alpha values than those further away (like looking in a fog).

I tried using

mfig=patch(p(:,1),p(:,2),p(:,3));

set(mfig,'facealpha',0);

set(mfig,'edgealpha',...

and then play with the different alphamappings but unfortunately I don't get it to work.

Does anyone know how to do this (if possible)?

Thanks!

Cheers, Filip

Answer 1

[Jonathan Sullivan]

amap = linspace(1,0,size(p,1))';
set(mfig,'FaceColor','none','EdgeColor','flat',...
   'LineWidth',3,'FaceVertexAlphaData',amap,...
   'EdgeAlpha','interp');

[Filip Persson]

Hi Jonathan,

Unfortunately it doesn't work; I get the following message

Warning: Patch FaceVertexCData length (0) must equal

Vertices length (233) for flat EdgeColor

Do you know what it means?

Thanks for helping me out!

[Walter Roberson]

Try adding

'FaceVertexCData', ones(size(amap))

[Filip Persson]

It works!

Thanks to Jonathan and Walter!

Answer 2

[Filip Persson]

The working script:

amap = linspace(1,0,233)';
mfig=patch(p(:,1),p(:,2),p(:,3),'red');
set(mfig,'facealpha',0);

set(mfig,'FaceColor','none','EdgeColor','flat',...
   'LineWidth',3,'FaceVertexAlphaData',amap,...
   'EdgeAlpha','interp',...
   'FaceVertexCData', ones(size(amap)));