Re: Line Tracing

[Roger Guay]

Thanks to all who have responded to this Line tracing thing. Here is another iteration.

Date: Sat, 1 Feb 2003 04:51:22 -0800
To: [EMAIL PROTECTED]
From: Jim Hurley <[EMAIL PROTECTED]>
Subject: Line tracing

I think I see the problem. It is not a difficulty with refreshing the
screen but the very large sampling times in the  trajectory
equations. If you  change "add 1 to T" to "add .05 to T" you  will
get a much smoother motion.  At least it does on my PowerBook running
OS 8.6

I have no problem with the motion . . . it's very smooth on my new iMac and several PC's I use. But you're right about the sampling time being a critical consideration.

But I thought you wanted a line drawn in the wake of the graphic motion?

Yes, that's exactly what I am trying to do. What I am trying to do reminds me of an oscilloscpoe where the persistence of the screen results in a line/trace from a moving spot on the screen.

I couldn't try your sound effects. They should add a nice touch to
the visual. I have seen discussions on this list of problems with
sound effects timing; that could be a conflict for you. I can't help
you there.

Since you're interested, I've emailed you privately to offer the download of my stack along with it's sound files.
I've experienced no timing problems with the sounds on my machines.

You  will find a number of these problems in dynamics illustrated in
the demo on the RR web site on the Education page including  the
projectile motion you are working on as well as planetary motion,
Kepler's 2nd law (planets sweep out equal areas in equal times), the
voyager sling shot effect as it moved around Jupiter and others. The
graphic I use there is the turtle, which I represent with an arrow
icon, which allows me to show heading as well as position. But it is
easily modified to move any one or more RR controls (buttons, fields,
graphics, images, etc.). You have the option of leaving a line in the
turtle's wake or not.

I've briefly looked at your TurtleGraphicsDemo and I'm very impressed. I haven't had time to understand the "Turtle" aspect yet, but I will have a closer look. I've been toying with the idea of simulating a typical Science Museum Foucault Pendulum, where a beautiful pattern is traced in the sand by the pendulum. I would like to generate those patterns by running the equation of motion of the Foucault Pendulum. I think this is not going to be easy because if I recall correctly, this is a non-linear differential equation. But, I'm ignorant enough to proceed anyway.

Thanks, Roger

_______________________________________________
use-revolution mailing list
[EMAIL PROTECTED]
http://lists.runrev.com/mailman/listinfo/use-revolution