The 3d graphics package for telnet sessions

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The 3d graphics package for telnet sessions

Release history
---------------
Release M1a - initial public release.
Release M1b - (Jan 26 2008) corrected coordinate
transformation formulas.

Program description
-------------------
The off2tek is a simple program displaying 3d graphics
on the Tektronix 4014 compatible terminal or emulator
(probably xterm). It's written in Korn shell and awk.

The input data is must be supplied in the Object File
Format (AKA off). Then the mesh is displayed using
axonometric projection. By default the military projection
is used, but you can change it by editing the script:

* FiX = 30; - specifies angle between the X axis
and horizontal direction.

* FiY = 120; - specifies angle between the Y axis
and horizontal direction.

* SX = 1; - specifies scale along X axis

* SY = 1; - specifies scale along Y axis

* SZ = 0.5; - specifies scale along Z axis

Z axis is always vertical. Note, that projection is not a
parallel projection (the 3d space is not transformed, but
mapped to arbitrary skewed coordinate system). For example
for isometry use: FiX=30; FiY=150; SX=1; SY=1; SZ=1.

On command line you can specify origin offsets and global
scale:

-x X_OFFSET - offset in X direction (in screen
coordinates)

-y Y_OFFSET - offset in Y direction (in screen
coordinates)

-s SCALE - global scale.

You can also specify input file with -f option, or send it
via standard input.

How to download
---------------
* Download the main script 'off2tek' and set it executable.

* Download sample off files 'vw.off' and 'teapot.off'.

* Switch your xterm to Tektronix mode - hold Ctrl and middle
mouse button, and select 'Switch to Tek Mode'. The Tek window
should open.

* Form command line enter:

TERM=tek

This will change your terminal settings, so issuing 'clear'
will cause to erase screen when it gets cluttered with
text and graphics. Don't forget, that in Tektronix mode
characters overstrike!

* Now enter:

./off2tek -x 210 -y 100 -s 500 -f teapot.off

You should get a big teapot on your screen. Now try:

./off2tek -x 550 -y 300 -s 6 -f vw.off

and you should see a VW bug.

There is no clipping algorithm implemented, so if your vectors
exceeds screen display gets corrupted. In such case you need
to adjust -s, -x and -y settings.

If you have any remarks, or improvements of the off2tek please
drop me a line at <[email protected]>