Combination Example : Flow and Particle Expression

To make the scene that the butterfly flying up from opening flower, I came up an idea using particle expressions we have been through. Particle Instancing is the key element of this scene because it can make the bunch of flying butterflies. I will connect the particle instance to the flow so the butterflies can emit following the guide funnel.  It is not as complicate as it sounds.

First, we will make the Flow which will be the guide funnel for butterflies.

1.  Create new scene. Create - EP Curve Tool and creat a curve as below picture in the front
     view.

2.  Name the curve to butterflyCurve. With the curve selected and select Create Deformer - 
     Lattice - Option box in the Animation menu set. Set the following and press Create.

     Divisions : 5, 9, 2
     Autoparent to Selection : On

3.  Select the ffd1Lattice node, Right mouse click on it and select Lattice Point. Select the top
     three rows of lattice points.

4.  Select Deform - Create Cluster - Option box. Check the Relative Mode on. Create.
     Repeat this step to create two more clusters.

5.  Select the three clusters in the outliner, then Shift - select the butterflyCurve. Press P to parent
     the clusters to the curve.

6.  Select tornadoCurve. At this time, butterflies are emitting out from the flower
     so we won't keyframe translations.

7.  Select butterflyCurveShape by pressing ↓key on the keyboard.

8.  Change to Dynamics menu set, select Effects - Create Curve Flow - Option box.
      Set the following and Create.

      Flow Group Name : butterflyFlow
      Num Control Sefments : 6
      Particle Lifespan : 3
      Goal Weight : 0.5

9.  Playback the animation.

10. Select the control_Circle_6 which is at the top of butterflyCurve and scale up the circle.
      Scale up the lower circles as look like below picture. 

11. Select the tornadoFlow and set Display Thickness on in the channel box. You will see
      the outline of butterfly funnel shape. Control the scale until you get the shape you want
      and set Display Thickness off again.

15. Select the butterflyFlow_particles, go to Fields - Vortex - Option box. Set the following.
      Create.

      Magnitude : 10
      Attenuation : 0

16. Parent the vortex field to butterflyCurve.

17. Select the butterflyCurveShape, Shift - select the vortex field. It will be easy to select in
      outliner. Select Fields - Use Selected as Source of Field.

18. Select vortex field, set Apply Per Vertex to On in the channel box. It will make every
      point on the curve emit field force.


Now, we will connect butterfly to flow.

19. Make simple butterfly model and duplicate 8 times. Arrange them on the Y axis.
      Hide the original butterfly. Rotate the wings of each duplicates as below.

20. Select butterfly1 through butterfly8 in order in the Outliner.
      Select Particles - Instancer (Replacement) - Option box. Set the following options. Create.

      Particle Instancer Name : butterflyInstancer
      Cycle : Se1uential
      Cycle Step Size : 1

      Make sure the butterfly1 to butterfly8 are in the Instanced Objects.

21. Hide butterflyParticles. Playback the animation.

Reference

• Autodesk Maya 2011, 2010. Autodesk Maya Online Help : Introduction. [online] Available at : < file:///Applications/Autodesk/maya2011/docs/Maya2011/en_US/index.html?url=./files/GS_Introduction.htm,topicNumber=d0e1838 > [Accessed 25 February 2011].

• Marc-André Guindon., 2005. Learning Maya 7 : The Special Effects Handbook. Unknown: Sybex