 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
JRG wrote:
> Well, this macro worked for me, and it looks quite physically realistic.
You could try having a look at mine, to see how they compare.
http://www.oyonale.com/ressources/english/sources07.htm
G.
--
**********************
http://www.oyonale.com
**********************
Graphic experiments
Pov-ray gallery
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
No strange formula. Just a bit of trig. The right formulae much depend on
your approach to the problem. My macro begins from a rotation value which
depens on the book position in the shelf (the books on the right are more
tilted) and on a random amount. Then it finds the distance of the book from
the previous one. Which is of course based on the rotation of the last book,
but also on the sizes of the two books (which could be different). So you
have to split your macro in several cases, because the formulae can be very
different.
For istance, suppose that the new rotation value is greater than the
previous one (a very common situation) and that the two books have such a
size that the second one leans against the previous one (and not viceversa).
If you indicate dist=(x coordinate of the point of contact between the
previous book and the *floor*) then you have to translate the second book to
dist+x_size_of_last_book/sin(radians(last_book_rotation))+y_size_of_new_book
*sin(radians(last_book_rotation-new_book_rotation))/sin(radians(last_book_ro
tation)) along the X axis. Just make a sketch on a sheet and you'll see
that.
--
Jonathan.
"Peter Hertel" <NOS### [at] hertel no> ha scritto nel messaggio
news:3b74150a@news.povray.org...
> > I've just written a little macro to place books on a library (I needed
it
> > for my irtc entry). The first queue uses a little amount of randomness,
> the
> > second one uses no randomness. Well, not much to say, I just liked the
> > effect and wanted to share it with POV community :).
> > (Oh, well, in my irtc entry I'm using books instead of 60ies coloured
> > superellipsoids...)
> >
>
> I've always wondered how you do things like that :-)
> Is it something like
> bookrotation = lastbookrotation*(some strange formula) ?
>
> Peter
> http://hertel.no/peter
>
>
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Oh, well, yours is far more complete! My 20 lines macro can't compete.
Surely the math involved is the same (I can't understand why people are
frightened by the simplest trig formulae). Here trace() cannot be handy,
because there's no problem about overlapping. BTW, if the angle of a book is
forced to be greater than the previous one, then you get a boring but
physically correct result (just like the queue with no randomness in my
image).
Jonathan.
"Gilles Tran" <tra### [at] inapginrafr> ha scritto nel messaggio
news:3B74F5B0.BE41BBAC@inapg.inra.fr...
> JRG wrote:
>
> > Well, this macro worked for me, and it looks quite physically realistic.
>
> You could try having a look at mine, to see how they compare.
> http://www.oyonale.com/ressources/english/sources07.htm
>
> G.
>
>
> --
>
> **********************
> http://www.oyonale.com
> **********************
> Graphic experiments
> Pov-ray gallery
>
>
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
JRG wrote:
> Surely the math involved is the same (I can't understand why people are
> frightened by the simplest trig formulae).
Must be the same, since both show the same problem, i.e. books standing more or
less upright when they should be sliding. I guess that a complete book macro
would have to take into account factors like mass or friction, and I agree that
trace() doesn't give a solution. But overall, it looks nice enough to be useful.
G.
--
**********************
http://www.oyonale.com
**********************
Graphic experiments
Pov-ray gallery
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Hmm.. figured it out to be something like that. I'll taka a look at it
someday. I guess it uses a reqursive macro, which I honestlty don't
understand, but I'll take a look at that someday, aswell :-)
Thanks a lot for enligtening me!
Great picture btw! I like the pretty colors.. oooh :)
-Peter
> No strange formula. Just a bit of trig. The right formulae much depend on
> your approach to the problem. My macro begins from a rotation value which
> depens on the book position in the shelf (the books on the right are more
> tilted) and on a random amount. Then it finds the distance of the book
from
> the previous one. Which is of course based on the rotation of the last
book,
> but also on the sizes of the two books (which could be different). So you
> have to split your macro in several cases, because the formulae can be
very
> different.
> For istance, suppose that the new rotation value is greater than the
> previous one (a very common situation) and that the two books have such a
> size that the second one leans against the previous one (and not
viceversa).
> If you indicate dist=(x coordinate of the point of contact between the
> previous book and the *floor*) then you have to translate the second book
to
>
dist+x_size_of_last_book/sin(radians(last_book_rotation))+y_size_of_new_book
>
*sin(radians(last_book_rotation-new_book_rotation))/sin(radians(last_book_ro
> tation)) along the X axis. Just make a sketch on a sheet and you'll see
> that.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
JRG wrote:
>
> I can't understand why people are frightened by the simplest trig formulae
Could it have to do with their having been exposed to trig through the
wonderous public education system?
--
David Fontaine <dav### [at] faricynet> ICQ 55354965
My raytracing gallery: http://davidf.faricy.net/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> Could it have to do with their having been exposed to trig through the
> wonderous public education system?
Mostly... I wonder how I hated maths at school. Now I understand that
what I hated was the system, no the things I was learning.
I also think that now maths can be learned in a less "abstract" way: I
myself know some teachers who use pov to graphically show maths to kids,
and they said it works pretty well to have them interested.
--
Jaime Vives Piqueres
La Persistencia de la Ignorancia
http://www.ignorancia.org/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:3B763F40.F0EACEFF@ignorancia.org Jaime Vives Piqueres wrote:
> I also think that now maths can be learned in a less "abstract"
> way: I
> myself know some teachers who use pov to graphically show maths to
> kids, and they said it works pretty well to have them interested.
>
http://www.inetarena.com/~pdx4d/ocn/numeracy0.html
uses POV-Ray and Python to teach math.
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
