Hi,
I've been trying out spline paths for the first time. There are many options
available to do this, and it's all rather confusing. I found that
"spline.mcr" seemed to be the easiest to understand and use. I did not see
any reference in the tutorial or elsewhere to moving multiple objects (such
as a train on curvy tracks or heavy traffic on a winding road) along the
spline. I would guess that it would involve adding some kind of clock
variable to each object, but I have no idea how to go about it. Do any of
you out there know how to do this?
Steve Shelby

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"Steve Shelby" <ssh### [at] rexnetnet> wrote in message
news:3ee09627@news.povray.org...
> "spline.mcr" seemed to be the easiest to understand and use. I did not see
> any reference in the tutorial or elsewhere to moving multiple objects
(such
> as a train on curvy tracks or heavy traffic on a winding road) along the
> spline. I would guess that it would involve adding some kind of clock

Hi Steve.

Well, actually the spline itself can accept 'clock' as the variable (if
animating, as other such animations are done) so you would just apply your
spline to each object for the motion to occur. For a train or traffic you
would need them to use offsets within one originating spline or make several
individual splines having the same path yet different starting/ending 't'
values. Probably some complex way of doing it too but that's the simple
explanation.

Take a look at splinefollow.pov, in the scenes\animations subfolder, since
it shows a good example of what you are wanting to do.

Bob H.

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Hi,
I went back to Chris Colefax's Spline Macro tutorial,
http://www.geocities.com/ccolefax/spline/ , and using one of the example pov
scenes, and making some changes, I was able to get multiple objects, but I
still can't figure out how to keep the spacing the same throughout the
animation. I emailed Chris about this and am still waiting for an answer.
By the way, I found the "roller coaster", and although it is an awesome
animation, The only moving part is a single marble, so that's no help. When
I get the time, I will try out your suggestions about delta time.
Steve Shelby

"squidian" <squ### [at] localhostlocaldomain> wrote in message
news:3ee565cb$1@news.povray.org...
> On Fri, 06 Jun 2003 09:24:51 -0400, Steve Shelby wrote:
>
> > Hi,
> > I've been trying out spline paths for the first time. There are many
> > options available to do this, and it's all rather confusing. I found
> > that "spline.mcr" seemed to be the easiest to understand and use. I did
> > not see any reference in the tutorial or elsewhere to moving multiple
> > objects (such as a train on curvy tracks or heavy traffic on a winding
> > road) along the spline. I would guess that it would involve adding some
> > kind of clock variable to each object, but I have no idea how to go
> > about it. Do any of you out there know how to do this? Steve Shelby
>
> It is not clear how much you know in asking this question. So let me
> start and tell me if I am insulting you.
>
> A spline is just a smooth curve between fixed points. If you remember
> curve fitting back in high school algebra it is basically the same thing.
>
> Adding a clock variable is delta along the spline.
>
> location(object_1) = spline*delta_time
>
> Obviously delta_time is most simply a function of the clock variable.
>
> There is a IRTC winner from a few years ago which is a ride on a roller
> coaster. You might wish to look into that and contact the author.

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Here i have 8 horses running along 4 splines:
http://cvs.buckosoft.com/Projects/pov/ttho/directHoss.inc?rev=1.4&content-type=text/x-cvsweb-markup

The Big Lesson is that life begins at 0 and ends at 1.
When coding an animation, you need to get each movement to run from 0-1.

So i calculate each horse's start and end time and make that a f(0-1).
Each horse that runs behind (starts later) on the track simply has his start
and end time moved down.

dik

(BTW, Press my Caps Lock and call me clueless, but i just recently discovered
the amazing Chris Colefax Spline Macro.  No longer will i have to hand code
my animation splines.)

--

Steve Shelby wrote:
> Hi,
> I went back to Chris Colefax's Spline Macro tutorial,
> http://www.geocities.com/ccolefax/spline/ , and using one of the example pov
> scenes, and making some changes, I was able to get multiple objects, but I
> still can't figure out how to keep the spacing the same throughout the
> animation. I emailed Chris about this and am still waiting for an answer.
> By the way, I found the "roller coaster", and although it is an awesome
> animation, The only moving part is a single marble, so that's no help. When
> I get the time, I will try out your suggestions about delta time.
> Steve Shelby
>

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