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Author translate and rotate
Fenrir

2005-05-26, 4:21 am

I want to animate the
crankshaft..(http://perso.wanadoo.fr/promethee60/3D/world.wrl )

How to do?
First of all ; translation of OA
second rotation determined by cross product;

if OB is on X my vector for cross product are
U | 1 AB | Racine ( Lē - Rē sinē wt )
| 0 | 0 - R sin wt
| 0 |0

also I have a rotation vector W = U^AB and sin RotAB = U^AB / || U ||* ||
AB||
Is It good?
I must apply translation before rotation?


A
|
Soit O--C-----------B

OA | R cos wt OB | R cos wt + Racine ( Lē - Rē sinē wt )
| R sin wt |0
| 0 |0


Thanks


Joerg Scheurich aka MUFTI

2005-05-27, 7:33 pm

Sorry.
For me, your post need a bit more english to understandable.
I found in a dictionary, that "racine" translates to squareroot
but it looks like, some of your mathematical symbols look very french
to me...
Is there a special french notation of mathematics ?

> How to do?
> First of all ; translation of OA


What is a OA, a 2D or a 3D vector ?

> second rotation determined by cross product;


> if OB is on X my vector for cross product are


What is a OB ?

> U | 1 AB | Racine ( Lē - Rē sinē wt )
> | 0 | 0 - R sin wt
> | 0 |0


What is U, what is AB, what is L, what is R ? wt could be a angle
resulting from a spinning object....

What means the symbol of the whole structure ? Matrix, determinate ?
Is this a lazy form with not writing down all | or 0 ?

> also I have a rotation vector


What do you mean with "rotation vector" ?

A Quaternion or a "direction multiplied with the cosinus of the angle" ?

> W = U^AB and sin RotAB = U^AB / || U ||* ||
> AB||


Should i read this as

sin(RotAB) = U^AB / ( ||U|| * ||AB|| )

???

Then it would look a bit like a formula for a cross product, if "RotAB" would
be the angle between the vectors U and AB.

But i never saw someone, who used the ^ symbol for the norm of a cross product.

All books i have seen use "A X B" or "A x B" for the cross product
and || A X B || for its norm.

> A
> |
> Soit O--C-----------B


What is a "Soit" ?

What does the whole symbol mean ?

For the whole question, maybe

http://www.web3d.org/x3d/specificat....html#Transform

| The translation, rotation, scale, scaleOrientation and center fields define a geometric 3D
| transformation consisting of (in order):

| a.a (possibly) non-uniform scale about an arbitrary point;
| b.a rotation about an arbitrary point and axis;
| c.a translation.

points in the direction, you are asking about...

so long
MUFTI
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