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1991-06-15
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124 lines
New & Improved Metamorph Desk Accessory
This new version of Metamorphosis has some niceties
that the earlier version did not. To begin with, it no longer has
the name-length bug(s). CTL filenames, .3D2 files and output-file
names can be up to 80 characters in length now. Of course, this
includes ALL characters, including pathnames and extenders.
The next (and best) improvement is in the memory usage. Meta4 only
stores the face-info for the first key-object(s). This is because
the face-info doesn't change from frame-to-frame, just the vertex
(ie, coordinate) information. Since objects may have 2X the number of
faces as vertices, this is important. Especially since each face takes
8 bytes of storage. In addition, on bootup Meta4 now "guesses" on how
much memory you wish to reserve for it; it then puts up an alert box
telling you how much it wants to reserve. It it is too much, click on
the "too much" box and it will decrease the amount by 50K. MegaST users,
with more memory, will appreciate this feature the most.
In order to re-use the face info, Meta had to be extensively re-written.
It has also been cleaned up quite a bit, since I took the opportunity to
run the C code thru MWC's compiler to see what it thought of the code.
I found many warning messages and comments on unused variables, so that
is all to the good...should make the program more robust. It also came out
a lot smaller when compiled under MWC. The changeover from the fast
floating point to the slower math package in MWC did not make much
difference in overall execution speed.
There have been no changes to the control-language, except to add the
keyword END, so that either STOP or END will work. This is because I
kept trying to use END, and Meta complained. Computers are picky that
way.
The original program was part of an article written for the now-defunct
STart magazine. I sent them an early version of Meta4 but they never
saw fit to distribute it. But since the new program is slightly based on
the old, please note the following:
"This program is not for resale. It is NOT in the public domain, although
you may make as many copies as you wish, as long as this file accompanys
any copy you distribute."
While writing the new version, I ran across a very subtle bug which
required a special "hack". If this program breaks in an unusual way,
please save the control and .3d2 files and send them to me. I want to
get to the bottom of the problem, but it's a difficult one (I can't tell
if it is a OS bug, CAD-3D bug or mine!). This bug, although I seem to
have squashed it, seems to be associated with rainbow TOS.
Mark Kimball 6/15/91
APPENDIX
Here's a recap of the commands that Meta4 understands, plus an example
of a control file. NOTE Meta4 is case-sensitive!
frames usage example: 15 frames
load example: load bird00.3d2
begin example: begin birdani
doit usage: doit (only usage)
stop usage: stop
end usage: end (does the same thing as STOP).
Here's an example of a control file. It shows how you can load several
files, do a metamorphic animation on them, and then load some more, etc.
load w1.3d2
load w2.3d2
load w3.3d2
10 frames
begin wtest
doit
load w3.3d2
load w2.3d2
load w1.3d2
15 frames
doit
stop
NOTES
You cannot include comments in the control file; this will confuse
the interpreter. Blank lines are OK.
Don't include a file extender for the output file-name following "begin".
Meta4 will do it for you.
Metamorphed objects in the .3d2 files must share common names as well
as common face structures. Here's an example of what I mean:
First 3d2 file contains: "bird","ball" and "dog".
All subsequent files, up to a "doit" command, MUST contain these 3
objects. Each object in each file must share a common ancestry. In
other words, you can't use a cube named "cube" in the first file and
a sphere named "cube" in the next file. Meta4 compares the face-structure
of all similarly-named objects and complains if they don't match. So, the
objects can be mashed, squeezed, scaled, rotated or moved, but they
have to be topologically equivalent. Meta4 is too stupid to use any other
type of object. Anyway, using the same name in subsequent files makes
it a LOT easier to create key-frames in CAD-3D.
After a "doit" command, you can start over again with object names, so
the next set of loads can contain, for example, just "bird" and "dog".
CyberSculpt sometimes will alter face-structures if objects are
distorted too much. The magnet tool seems to be especially bad for
this. So you may have to experiment to see what works and what doesn't.
Good Luck! Happy Animating!
Mark K.