On Thu, 12 Mar 2009, Bilbo Baggins wrote:

> Hi Mark,

>   I have a question regarding the pool table assignment.  How do we edit
> the balls so they fall into the holes?  They move, just just a little.  
> I can't find anywhere on the instructions to actually make them fall into
> the holes.  Also, when we created the holes in class- we created a
> cylinder and then deleted it out.  What menu was that under?
> I forgot the name of the action.

   Creating the holes so they are round instead of square holes:
   ------------------------------------------------------------

   It was Mesh menu > Booleans submenu > Difference command

   Polygons menu set, of course, has the Mesh menu.

   Select the Polygonal Cube (pool table surface object) first, 
      then Shift-select the Polygonal Cylinder second.

   Then the Mesh> Booleans > Difference command will take away the 
      Cylinder, leaving a hole in the pool table surface.

> 
> Thanks, 
> Bilbo Baggins

-----------------------------------------------------------------------------

   Date: Thu, 12 Mar 2009 12:55:48 -0500 (CDT)
   From: Mark Jacobson <jacobson@cns.uni.edu>
     To: Bilbo Baggins <BilboBaggins@MiddleEarth.com>
Subject: Re: Pool table question

Bilbo,

    Don't you have the orange handout I gave out?

    The instructions for doing what you ask are on the handout, they are 
NOT on the web site.  

    I will type in and elaborate what is on the orange handout.

    ----------------------
    Animating Rigid Bodies
    ----------------------

    The next step is to put the cue ball into motion so that it hits
the other ball or other balls and sets them into motion.

    The easiest way to do this is to keyframe the cue ball's translation
from its starting point to hit the striped ball.  (Note: you probably do NOT
have any striped pool balls, as we have not gotten to the texturing part of
the Maya class yet).

    But since active rigid bodies cannot be keyframed, you have to turn the
cue ball into a passive rigid body.  
                ------------------

    (It was made into an ACTIVE RIGID BODY earlier, along with all the
     pool balls - you probably have either 3 pool balls or 11 pool balls).

    To turn the cue ball into a passive rigid body so that it can be
keyframed and set into motion to strike the other pool balls, follow
these steps:

    1.  Select the cue ball (the white ball or whatever ball you want
           to "shoot" into one of the other pool balls or into the racked
           up set of 10 pool balls).

    2.  Rewind your animation to the first frame.

        Choose Soft/Rigid Bodies > Set Passive Key

        Notice when you look at the Channel Box that the Active attribute
           has turned a dark yellow.

        You have set a keyframe for the active state of the cue ball, and
           now it reads Off.  

           Active attribute reads OFF.
           Active attribute did read ON before.

        You can toggle rigid bodies between active and passive.  Maya has
           also just set translation and rotation keyframes 
           for the cue ball.  Check out the channel box.

        TranslationX, TranslationY and TranslationZ attributes are the
           relevant ones here.

    3.  Go to frame 10.  Move the cue ball with the Translate tool (the
           move tool R or G or B manipulator handles) so that the
           outer surface slightly passes through the pool ball you want
           to "hit" with it.

        Choose Soft/Rigid Bodies > Set Passive Key

        Now you have a key frame at Frame 10 or whatever frame you
            chose for where the cue ball hits the other pool ball.

    4.  Go to frame 11.  Choose Soft/Rigid Bodies > Set Active Key.

        This will turn the cue ball back into an active rigid body
        in the frame right after it strikes the other pool ball.

    Summary:

    You animated the cue ball as a passive rigid body and keyframed its
       translation from frame #1 to frame #10.

    At frame #11 you turned the cue ball back to an active rigid body.
       This sets the dynamic (APS D R = APSDR) simulation into motion.
                               -        -

    The cue ball animates from its start position in frame #1 to frame #10
       where it "strikes" the other pool ball.  At frame #11 of the
       animation, the Maya dynamics engine takes over and calculates
       the reaction of the struck pool ball and it and the cue ball bounce
       off each other and Maya takes over from there.

    I am sure this should help.  It should all be on the orange handout
too, but maybe you did not get that.  There should still be one taped
outside my office door, 307 ITT.

    Mark