View Full Version : Question: Hard FX and Rotation Channel

07-14-2004, 10:46 PM
The dynamics setup is pretty simple and works really well: Some balls fall down, hit the paddle wheel, and the wheel starts rotating.

But the bank rotation channel of the wheel doesn't get affected by the dynamics calculation (it stays at "0.0"). I would like to use the same rotation around the Z axis for another object. I tried parenting another object to the wheel but that doesn't work.

Is there a way to transform the rotation that is calculated by the Hard FX engine into a usual rotation on the bank channel?


07-14-2004, 11:07 PM
Do the balls get diverted a bit depending on how they hit the spoons?
I was working on a similar setup for the trebuchet/catapult competition, and while i could get the arm to be affected when a ball hit it, the ball would essentialy keep falling straight, not bouncing off the arm.

07-14-2004, 11:16 PM
Yes, the dynamics simulation looks pretty realistic. I will post the animation when it's done.

Now I would like to drive the bank channel of another object with the same rotation. Any idea how to achieve this?

07-15-2004, 12:06 AM
lol, you trying the FX Challenge arent you?!

07-15-2004, 12:40 AM
i can't think of an easy way. of course, i'm no expert.
it's probably a feature request for newtek. since the object can be broken into parts, it's probably easier for them to leave the object's axis alone and focus on the polygons and points.

Perhaps it would be possible to write an lscript to calculate the bank, heading, and pitch of an 'edge' on the object and return the result for use in an expression. a clever person could make the script use the first edge found and then calibrate that with the objects heading and report the relative change. too bad i'm not that person.

07-15-2004, 03:29 AM
LOL, just started the Trebuchet myself. The only way I found to get things to not go through each other is to slow the drop down or to increase the density.

allaboutkeys: Do you have a wireframe?

07-15-2004, 07:16 AM
No, I'm not taking part in the challenge. Does my object look like a catapult?!? :)

07-15-2004, 07:17 AM
well, ya, kinda!

im confused tho, about what you want to do with this and the bank channel??
where is the avi?

07-15-2004, 11:21 AM
Kvaalen on spinquad.com found the solution: http://www.spinquad.com/forums/showthread.php?s=&threadid=2160

Ok, here's what I needed it for: I wanted to simplify a Hard FX setup with several collision items. Have a look at the image and the animation below: The wooden disc with the pin isn't part of the dynamics calculation, it's just parented to the null object that was created by the "Make Path" command.

Now I can apply Collision FX to the disc object and let it hit some other items (that are not yet there in the scene). I am trying to setup a kind of "chain reaction" of several hard body objects without putting too much load on the dynamics calculation.

paddlewheel_320x240_01.avi (http://www.allaboutkeys.com/lightwave/paddlewheel_320x240_01.avi) (AVI, DivX 5.0.5, 1.3 MB)


07-15-2004, 02:02 PM
glad to know the fix. much better than what i proposed. :)
I notice that the ball does still fall straight down, even when it touches the paddle. Only when it hits the ground does it bounce in a different direction. I guess I can't have it both ways.

One thing is for sure, I need to read the manuals. I still haven't bothered to download them yet.

CGTalk Moderation
01-18-2006, 05:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.