s.day schrieb:
> http://www.irtc.org/ftp/pub/stills/2006-08-31/oldroyal.jpg
> 
> I even had a go at animating the wheels..

That's really impressive quality. (You're aware though that the 
animation must be from a train going downhill? The reverse lever is 
apparently at neutral, effectively locking the valve in dead center 
position so it doesn't admit any steam to the cylinder...)

Would you mind me using parts of your code? (Probably not, or you 
wouldn't have published the code in the first place, but I rather ask 
anyway.)

Post a reply to this message

clipka <ano### [at] anonymousorg> wrote:

> That's really impressive quality. (You're aware though that the
> animation must be from a train going downhill? The reverse lever is
> apparently at neutral, effectively locking the valve in dead center
> position so it doesn't admit any steam to the cylinder...)
>
> Would you mind me using parts of your code? (Probably not, or you
> wouldn't have published the code in the first place, but I rather ask
> anyway.)

I didn't know how the levers work and the train was modelled from photos found
on the web so I was pretty sure it wasn't very accurate as most of the images
didn't show the wheels/levers in enough detail to model and I had no idea how
they should move.

When I modelled the train I had lots of scenes in my head that I was planning to
use it in but never got the carriages finished (I ran out of steam :~o ).

I would be glad to see any part of it in another picture so you are free to use
it (if you can make anything from my poorly written/commented code).

Sean

Post a reply to this message

AWESOME good looking animation! Just let the wheels turn in the right 
direction...

The wheels turn clockwise when the motive gear turns anti-clockwise? Is this 
an error in the animation or am I missing something? Even going downhill the 
wheels should turn the same direction as the gears.

BTW: here's a link to an animation (less beautiful - more technical)

http://en.wikipedia.org/wiki/File:Walschaerts_motion.gif


"clipka" <ano### [at] anonymousorg> schrieb im Newsbeitrag 
news:4a946d82$1@news.povray.org...
> s.day schrieb:
>> http://www.irtc.org/ftp/pub/stills/2006-08-31/oldroyal.jpg
>>
>> I even had a go at animating the wheels..
>
> That's really impressive quality. (You're aware though that the animation 
> must be from a train going downhill? The reverse lever is apparently at 
> neutral, effectively locking the valve in dead center position so it 
> doesn't admit any steam to the cylinder...)
>
> Would you mind me using parts of your code? (Probably not, or you wouldn't 
> have published the code in the first place, but I rather ask anyway.)
>

Post a reply to this message

"TC" <do-not-reply@i-do get-enough-spam-already-2498.com> wrote:
> AWESOME good looking animation! Just let the wheels turn in the right
> direction...
>
> The wheels turn clockwise when the motive gear turns anti-clockwise? Is this
> an error in the animation or am I missing something? Even going downhill the
> wheels should turn the same direction as the gears.
>
> BTW: here's a link to an animation (less beautiful - more technical)
>
> http://en.wikipedia.org/wiki/File:Walschaerts_motion.gif
>
>

Thanks for the link, the wheels are turning in the right direction, it is just
an illusion that make it look like they are not. The whole wheel object is
rotated so if they were not turning the correct way the part where the lever is
attached would also go the wrong way.

Even though I knew this I had to colour the spokes individually to make sure I
had not made some mistake somewhere as the effect just doesn't look right.

Sean

Post a reply to this message

"s.day" <s.d### [at] uelacuk> schreef in bericht 
news:web.4a946587d8f21fa2b51465700@news.povray.org...
> This reminds me of a train I modelled several years ago (the royal scot) 
> it was
> pretty much the last image I did, in fact the effort probably finished be 
> off..
> ;-) Hope it doesn't have the same effect on you..
>

That was an inspirational image, I remember. Still one of my top favourites.

I sincerely hope you will be back with us. Pity to have stopped...

Thomas

Post a reply to this message

"Thomas de Groot" <tDOTdegroot@interDOTnlANOTHERDOTnet> wrote:
> That was an inspirational image, I remember. Still one of my top favourites.
>
> I sincerely hope you will be back with us. Pity to have stopped...
>
> Thomas

Hi Thomas,

Thanks, I'm glad the effort was worth it. I recently found out the IRTC has been
resurrected so with only 2 weeks to go have attempted to put together an image
for the first round (this made me realise how rusty I am though, can't believe
it was 2006 last time I did an image..)

Not entirely happy with it but I will submit it and hope to do better in the
next round.

Sean

Post a reply to this message

s.day wrote:
...
> 
> Thanks for the link, the wheels are turning in the right direction, it is just
> an illusion that make it look like they are not. The whole wheel object is
> rotated so if they were not turning the correct way the part where the lever is
> attached would also go the wrong way.
> 
> Even though I knew this I had to colour the spokes individually to make sure I
> had not made some mistake somewhere as the effect just doesn't look right.
> 
> Sean
> 

It's just the same stroboscopic effect you often see in movies where the 
wagon wheels appear to go backward.

It's basically this -- assume for example, the spokes are 10 degrees 
apart and the timing lets them move 8 degrees clockwise each frame. 
This will give the appearance of them moving 2 degrees counterclockwise 
each frame.  Perhaps you can play with the timing to come up with better 
results, but I have no specific suggestions of how to do this.

      -=- Larry -=-

Post a reply to this message

In this case the solution is easy: simply add more frames (or less). I'd try 
either 17 or 34. If I've counted right then at 21 frames the wheels should 
seem to stand still ;-)

Then, since you already have 25 frames, why not go for 50 frames?

Post a reply to this message

> AWESOME good looking animation! Just let the wheels turn in the right 
> direction...
> 
> The wheels turn clockwise when the motive gear turns anti-clockwise? Is this 
> an error in the animation or am I missing something? Even going downhill the 
> wheels should turn the same direction as the gears.
> 
> BTW: here's a link to an animation (less beautiful - more technical)
> 
> http://en.wikipedia.org/wiki/File:Walschaerts_motion.gif
> 
> 
> "clipka" <ano### [at] anonymousorg> schrieb im Newsbeitrag 
> news:4a946d82$1@news.povray.org...
>> s.day schrieb:
>>> http://www.irtc.org/ftp/pub/stills/2006-08-31/oldroyal.jpg
>>>
>>> I even had a go at animating the wheels..
>> That's really impressive quality. (You're aware though that the animation 
>> must be from a train going downhill? The reverse lever is apparently at 
>> neutral, effectively locking the valve in dead center position so it 
>> doesn't admit any steam to the cylinder...)
>>
>> Would you mind me using parts of your code? (Probably not, or you wouldn't 
>> have published the code in the first place, but I rather ask anyway.)
>>
> 
> 
> 
It's just an illusion.
You can, sometimes, see just the same in a movie.

I remember one where you see a big agricole tractor spoked weel complete 
with heavy treads and 2 circles of bolts. You had the illusion that the 
treads and one circle of bolts where turning backward, at different 
speeds, one circle of bolts turned veeeeryyyy sloooowly in the right 
ditection, and the spokes turned to fast in the correct direction.

It was facinating :)


Alain

Post a reply to this message

s.day schrieb:

> This reminds me of a train I modelled several years ago (the royal scot) it was
> pretty much the last image I did, in fact the effort probably finished be off..
> ;-) Hope it doesn't have the same effect on you..

Well, I guess by now I'm getting a feeling of what you're talking about...

(still on the :-) side though... I think.)

Post a reply to this message