Riddle of the day. (Track rotation)

farss wrote on 5/24/2004, 12:46 AM

I'm trying to get an object to start from stationary, spin up, hold speed for a few seconds and then slow back down to a stop back to the same position. Intention is that this can then be looped to produce a constant rev up, rev down. All would seem simple except for using event velocity to slow down to an exact frame.
I thought I had it in the bag by reversing the event but that also reverses the direction of rotation, damn.

Not really that important but now the idea is in my head I cannot get it out of there.

Comments

TorS wrote on 5/24/2004, 1:45 AM

You have to test this, because it's only a theory:
When you set a velocity envelope to freeze on an exact frame but want it to slow down gradually, you must set the curve the way you want it and then pull the event's lenght to the left, to make up for the time spent on the slowdown.
Tor

Tested it myself. It's worthless. See below. T

TorS wrote on 5/24/2004, 1:59 AM

If you're slowing down from 100% you may try this: Set markers on both sides of the exact frame you want. Make a velocity point on each, and set the rightmost one to zero. That ought to compensate for the difference between slowing down and stopping abruptly.
Tor

farss wrote on 5/24/2004, 2:51 AM

That's pretty much what I've ended up doing. Obviously the right handmost one has to be at zero velocity, I need the rotation to stop for a few frames. I can get it extremely close by moving the point at which the slowdown starts while wtaching just to the right of the righthand node to see at what point its frozen. What makes it hard is there's no way to move the nodes in just one direction at a time.
I've got it to within about 2 deg of being spot on.

The other approach I could try is to go back one step to where I created the rotating object and set more keyframes but that's going to make it hard to create the illusion of the speed ramping up and down.

Thanks for trying, I might need to sleep on this one!

Bob.