Deformers copyright of Giulio Porta 2006, all rights reserved.

Deformers are virtual geometric objects that effect the shape and behavior of other geometric shapes. Deformers don't render therefore they are not visible in your scene's final version.

The deformer that we are going to use to simulate the fish's fishtailing, is shaped like a box and goes by the name of Start Deforming by Stand Alone Box.

Deformers behave like objects, they can be as a whole moved scale and rotated like any other object in the scene. But when it comes to their inner structure deformers have their own set of dedicated tools.

Once a deformer such as the Stand alone box is going to be deformed any other object attached (glued) to it, will assume the same type of deformation given to the deformer.

During a deformation the object to be deformed must be always inside the deformer.

Deformations can be animated

  1. Load the fish and move it to the far right or left of the work space, away from its center.
  2. Load the Standalone Deformation Object (the box) by clicking on its icon. It will load in the middle of the work area.
  3. if you are using v 6 or higher, as soon  as you select a deformer, the context tools box will pop up, drag it to the side, out of the way.



After the deformer box is loaded and BEFORE YOU DO ANYTHING ELSE,  you'll need to add more cross section along the direction the fish will swim.

For v 6 and higher: Zoom in on the deformer and look for a tripod at the bottom of the deformer, place the cursor on the arrow pointing toward the direction along which the fish will swim hold the Left mouse button down and drag. As you do so you'll be adding more cross sections along the direction you are dragging.

6 up to 8 cross sections will do. The number of cross sections represents the number of times the fish will be deformed. The cross section at the beginning and the end of the box don't count and they should not be moved. If you place too many cross sections drag your mouse in the opposite direction

For earlier versions, ad more cross sections as follows:

L click+ hold and drag outside the box along its length, as indicated by the double headed arrow in the illustration here above. If you place too many cross sections drag your mouse in the opposite direction. You should have 6 to 8 cross sections. This operation take some practice.

Setting up the fish

After adding the desired number of cross sections, with the object scale tool scale the whole deformer length wise, make sure that the distance between the cross section is at least or greater then the length of the fish.

Place the fish inside the deformer box at one end of the deformer. Use 3 view to make sure that the fish fits comfortably inside the deformer.

Deforming the deformation box
  • Switch to a top view.
  • In the Deformation tools panel choose the icon Deformation along a plane perpendicular to Y axis. If you deformation box lays along the X axis, please choose the Deformation along a plane perpendicular to X axis.
  •  You will notice that all the cross sections perpendicular to length of the deformer or the direction along which the fish will swim, will be highlighted or turn green.
  •  You will need to rotate them slightly, with the rotation tool available within the same panel. To do this rotation you must be in top view, R + click anywhere on the screen to rotate the cross section. You must rotate one cross section at the time.
  • You MUST LEAVE THE TWO ENDS OF THE DEFORMER BOX ALONE, parallel to each other. Do not rotate them or alter their position, this will have an adverse effect on the fish. When entering the deformer box, its polygons will tear up.
  • The angles of rotation of each cross section do not have to be identical. It would be best if they were slightly different. They should also alternate, left right, left, right and so on.
  • When the fish will go through them, it will bend according to their angle.




Attaching the fish to the deformer
  • In order to do so you must have the deformer box active.
  • from the deformation tools select one named Start Deforming by Stand-Alone Deformation object.
  • Click on the fish, this action will create a relationship between the fish and the deformer, the deformation given to the deformer box will deform the fish as the fish moves through the box.
  • move the fish slightly forward, the fish will snap to the deformer bending according to the shape given to the deformer.









The Animation.
  • Place the fish to the starting point of its swim, which will be  at the far end of your deformer box.
  • There is no exact place, the fish could be slightly inside the deformer or completely inside.
  • Later the entire scene should be rotated if the fish needs to swim toward you.
  • The final choreography will involve several new elements such as a river bed, a "water plane" and caustic effects created with lights. But for now you must concentrate on the animation, everything else will get in your way.


  •  Your animation panel should indicate that you are at frame 0.
  • Now replace 0 with 210 by typing 210 in the # of frames field. 210 frames correspond to 7 seconds.
  • The paradigm that we are using is that of video speed play back which is 30 frames per second.
  •  Drag the fish to the end of the deformer box. 
  • Play it back, to preview it and watch for the result in a perspective view.
The fish can be copied and moved to create a school of fish, they could all swim in the same deformer box (the box must be scale larger) or in different boxes.
  • You could keep the fish in one place, animate its tail only by deforming it.
  • Have a camera moving toward the fish. This approach will yield the similar results with the exception of the head of the fish remaining steady and only the tail moving.
  • Have a camera moving along same direction that the fish is swimming, but not exactly at the same speed.