[ODE] Initial conditions problem

[Peter Yamamoto]

I'm also trying to understand the relationship between applying an initial force (dBodyAddForce) to an object for projectile motion, velocities, etc.

In particular, I want to be able to have a pretty good estimate/solution for hitting a moving target (given various parameters, fixed target velocity, known position/angle of projectile, etc).

Currently like Thomas, I think I want to frame the parameter/solution in terms of an initial velocity, but currently I am using an initial force value to shoot the projectile.

I've then queried the linear velocity after the first simulation step, but I'm not quite seeing the relationship (eg the one which would allow me to translate a desired velocity into the ODE impulse value that would generate that velocity).

I was just about to look more closely into the ODE stepper function but since somebody seems to be asking a similar question, I thought I'd add my interest in the question/answer.

Peter

-----Original Message-----
From: ode-bounces at q12.org [mailto:ode-bounces at q12.org] On Behalf Of Thomas Paviot
Sent: Monday, December 05, 2005 2:46 PM
To: ode at q12.org
Subject: [ODE] Initial conditions problem

Hello,

A human being throw a stone far away : i want to simulate the movement of the stone. When the stone leave the human's hand, the velocity vector is 1m/s with an angle of 45° with gravity vector.

Before starting an ODE simulation, at initial time, all velocities are equal to 0.0. Is it possible to apply initial velocity to a joint (or a
body) before starting simulation? It seems there is no builtin function to do that.

Anyway, do you have any tip to go around the problem?

Thomas
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