Re: A89: Basic -- 3Dstudio

To: <assembly-89@lists.ticalc.org>
Subject: Re: A89: Basic -- 3Dstudio
From: "Miles Raymond" <m_rayman@bigfoot.com>
Date: Wed, 16 Dec 1998 20:07:47 -0600
Delivered-To: assembly-89-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-89@lists.ticalc.org


I take it you haven't taken a Physics class yet...  vector and matrix multiplication is used a lot
with 3D models.  I remember a lot of this, but I can't really explain it.  We learned this last
year, but I forgot.  Now we are on friction, so I can't really help here.  If you can get a hold of
one of your school's physics books, then you could try to learn about vector and matrix
manipulation.

-Miles Raymond

-----Original Message-----
From: TurboSoft@aol.com <TurboSoft@aol.com>
To: assembly-89@lists.ticalc.org <assembly-89@lists.ticalc.org>
Date: Wednesday, December 16, 1998 8:25 PM
Subject: Re: A89: Basic -- 3Dstudio


>In a message dated 12/16/98 4:41:14 PM Eastern Standard Time,
>nlmueller@students.wisc.edu writes:
>
>> Moving a point <x,y,z> in the direction of the vector <a,b,c>
>>
>>  | 1 0 0 a |
>>  | 0 1 0 b | * <x, y, z, 1> = <x+a, y+b, z+c>
>>  | 0 0 1 c |
>
>how does this move a point in the direction of a,b,c?  help?
>
>>  Rotating a point m degrees around the z axes
>>
>>  |  cos(m) sin(m) 0 |
>>  | -sin(m) cos(m) 0 | * <x, y, z> = <x*cos(m)+y*sin(m), -x*sin(m)+y*co(m),
>z>
>>  | 0           0        1 |
>>
>>  Which makes sense if you remember your matrix multiplication
>
>?
>
>>  | a b c |    | x |     | ax + by + cz |
>>  | d e f | * | y | =  | dx + ey + fz |
>>  | g h i |     | z |     | gx + hy + iz |
>
>how can l make a point out of that answer?