Q: I am trying to create the effect of film unrolling off a film spool.How might I approach this? Any advice or help would very much be appreciated.

A: This is a nice example of using the PathDeform Space Warp that ships with MAX 1.1 and higher.


You can download the .MAX scene to play with...

Let's create the path for the film:

  • Start a new scene in MAX, turn Snap and Angle Snap on.
  • In the Front Viewport, create an Arc with Center/Start/End - start at "south" position and go to 270 degrees clockwise.
  • Create a second 270 degrees arc starting where the first ends. (You can repeat this again and again for longer films...)
  • Create a straight or bezier line stating at the start point of the first spline and ending somewhere to the right.
  • Apply an EditSpline to the shape, turn Sub-Object off and connect all splines to a single shape.
  • Go to Sub-Object/Vertex, select all and click on Weld - you have a single spline now.
  • If you have the free Normalize Spline modifier by P.Watje of Spectral Imaging, apply it to get a constant vertex count along the spline.

    Let's create the Film Spool and the Film objects:

  • Create a Tube with the radius of the arc for the core of the Film Spool.
  • Create a Ring with the same center and a larger radius for the side of the Spool.
  • Uncheck "Start new shape" and create the openings in the side of the Spool.
  • Apply a Bevel or Extrude Modifier.
  • Create an Instance for the other side of the Film Spool.
  • Select both side wheels and the core of the Spool and group them.
  • In the Top Viewport create a very long QuadPatch for the film and increase the segment count for the longer dimention.
  • Apply a UVW modifier and scale the Gizmo to the size of a single film frame.

    Let's create the Space Warps now:

  • Go to Create/Space Warps and click on PathDeform.
  • Select the spline for the path - a Space Warp will be generated.
  • Create a Wave Space Warp.
  • Select the spline again, add another EditSpline modifier and select the vertices outside of the spool.
  • Click on "More..." and apply XForm modifier.
  • Bind the XForm gizmo to the Wave Space Warp.
  • Bind the Patch to the PathDeform Space Warp, enter 90 for rotate, check "Move Object" and X.
  • Click on Animate and change the phase settings of the Wave on the last frame - the XForm with the outer vertices of the spline will be affected, and make the PathDeform move, too!
  • Now go to frame 0, turn Animate off, select the Film and change the Percent settings of the PathDeform in the SpaceWarp Binding until the film gets totally wrapped on the spool.
  • Go to the last frame, turn Animate on, and change the Percent settings to a new value until the film unrolls.
  • The last thing to animate is the rotation of the Film Spool group. You can try to set the angle that synchronises the spool rotation with the film. Or you could write an Expression to rotate the spool as the Percent of the PathDeform changes...

    Be sure to create nice materials and lighting for the scene... You will need a greyscale single frame image for the Opacity map on the film. It will repeat because we scaled the UVW modifier to the size of a single frame. Use Raytracing Shadows to project the opacity map of the single frames on the ground...

    Have fun!