How to draw a 3D point moving along a helical path?

Question

I have an animation for a helix being drawn in 3D but I really want to have a point on there that draws the helix. I've seen similar problems on here for 2D and I tried adapting the suggestions but I wasn't able to make anything work. I think it would be really cool to see a particle moving along this path. Any help would be greatly appreciated.

My code is as follows:

 Animate[ParametricPlot3D[{Cos[t], Sin[t], t/4}, {t, 0, u}, 
  ImageSize -> Small, PlotRange -> {{-2, 2}, {-2, 2}, {0, 8}}], {u, 0,
   30}, AnimationRate -> 3]

Answer 1

You can add a moving point using a combination of options MeshFunctions, Mesh, and Method as follows:

Animate[ParametricPlot3D[{Cos[t], Sin[t], t/4}, {t, 0, u},
      ImageSize -> Small, 
      MeshFunctions -> {#4 &}, 
      Mesh -> {{u}}, 
      MeshStyle -> Red, 
      Method -> {"BoundaryOffset" -> False}, 
      PlotRange -> {{-2, 2}, {-2, 2}, {0, 8}}] /. Point -> (Sphere[#, .15] &), 
   {u, 10^-6, 30}, AnimationRate -> 3]

\

Note: Used ReplaceAll to change the Point primitive to Sphere.

Answer 2

Another option suitable for convenient embedding of many graphics primitives is to use Show and Graphics3D:

Animate[Module[{a}, 
  Show[
    ParametricPlot3D[a = {Cos[t], Sin[t], t/4}, {t, 0, u}, 
      ImageSize -> Small, 
      PlotRange -> {{-2, 2}, {-2, 2}, {0, 8}}], 

    Graphics3D[{Red, Sphere[a, 0.15]}]]],

 {u, 10.^-6, 30}, AnimationRate -> 3]