Subject: Re: Page flip
From: Tyg <[email-masked]>
To: [email-masked]
Date: Wed, 27 Mar 1996 09:57:12 -0800

>For an intro I need a book that opens then the 2 or 3 first pages flip.
>
>I've been trying to flip a page for a while either by morphing well 
>prepared objects or with bones 'curling' a detailed flat box.
>

Yupp, did this a couple of years ago for a local television channel.  The
book opening is easy enough to affect, and with a little bone work and
morphing here and there you can get the whole thing to come out nicely.
Here's what this animator did...

Total of 5 objects (plus 2 additional for morph targets).  Book cover and
pages Left and Right being 2 of the five;  these have morph targets that
make the pages look like they're sloping as pages do when their book is
open.  2 objects for the pages that turn, and a final object for the book
spine.  

Make the pages that will be turning stand 'streight up' in the front view
(and model the other parts as if the book were lying open on a table
already) triple them and subdivide them so they bend smooth enough for your
anim.  If you're planning on having different maps on each side, you'll need
to copy the polys, rename, flip and past the oritionals (but you knew that
already).  If you do this, its important to remember to turn off
SELF-SHADOWing in layout otherwise you'll get wierd shadows as the bones do
their work.  Also tripple the book's spine/binding so that if you use bones
to deform it in accordance with the book opening, you won't get polygon errors.

Load all your objects in Layout and parent them to a null.  Dissolve 100%
the morph targets for the cover/solid pages if you're planning on doing the
morph, and move the rotation points for the cover/solid pages so they will
swing around believably.  Set key frames for the book opening, and set up
your morph envelope accordingly.  (I used bones to manipulate the spine of
the book so that it looked like the force of the book opening was pressing
on the worn leather binding.  If you do this too, just be sure to anchor it
well)

Now the pages turning are easier than you might think.  Set up at least 2
bones in the corners of the page to anchor the it in the center of the open
book pointing streight same as the page.  The put at least 2 more at the top
corners of the page also pointing streight up.  I parented my bones at the
top of the page to a single bone to make manipulating them easier,  Using
this phalanx of bones at the top of the page, you can rotate and move them
to get the page to fold quite realistically, the bones that anchor the page
into the books spine not only serve to anchor it, but to give the page some
stiffness adjusting their rest length and rotation will let you finess the
pages into flipping just like real life.  

As an animation tip for book pages turning, grab a big book (phonebooks work
nicely) and turn a couple of pages, watch how the pages turn, watch how you
turn the page, watch how your force affects the page as it moves.  I found
that if you don't have the bones at the top of the page turing perfectly
parallel to the edges of the book (rotating it so the whole thing swings to
the side just a bit as it prepares to turn) it looks like some invisible
force has grabbed a corner of the page.

Good luck, and if I'm not making sense, just let me know and I'll try to
clairify.

Timothy

BTW, its refreshing getting a post that actually focuses on working in
lightwave. -- IMHO