LW8; expression worked 8.2; doesn't

[neocount73]

Hello all. I created a LW 8.0 (or was it 8.1?) scene in which I rigged a rather intricate 6 wheeled Martian Roving Vehicle with working suspension, steering and an expression to spin the wheels as it moved forward. Everything worked honkey-dory until I installed 8.2. Now, I load the scene, move to a point on the timeline, pull the Master Null allong the Z axis (the wheels are a-spinnin', Chthulhu's in his heaven and all's right with the world), I move to a diffent point on the timeline and *BLIP!!* that sonofabiscut Master Null returns to it's starting point! No animation of it moving to the next keyframe, no spinnin' wheels. I've tried deleting the expressions and re-creating and re-applying them. No results. Any help will be rewarded with creamy, chocolate covered karma, and my heaping thanks. Here are the expressions (derived from the "Pedal Copter" tut on the main Lightwave site) :

MRV_locator
vmag( MRV_mov.pos(Time)- MRV_mov.pos(0))
(applied to the MRV_mov (Master Null) Z axis)

Tire_rot
360*vmag( MRV_mov.pos(Time) - MRV_mov.pos(0))/6.858
(applied to the wheels Pitch)

[Castius]

Do i dare ask if autokey is on?

[neocount73]

HA! OK, should have put that in the main body of the message, Castius, sorry. I have indeed tried it both ways actually (autokey on, auto off+ create key, etc.) Still the same result, or LACK OF result. Even after 8 years using Lightwave I do still make rookie mistakes, and with expressions in LW my experience is liliputian, sadly. This scene DID work before, honest injun, I've got the renders to prove it, HA HA! Has anyone else had problems with their expressions in the switch from 8.* to 8.2?

[Castius]

Is it possible for you to send me the scene so i can try it?

[neocount73]

Well, Castius, I couldn't send you my scene due to file size and ye old "Nondisclosure Blah blah" so I created a scene to send with nulls using the same expressions and heirarchy setup and, lo and behold, it worked. Now it's a matter of choosing wheather or not to redo my vehicle setup or debug my current scene. I'm ****ed either way. :(

[Castius]

Well thats a start. Try ripping down your non working scene till it matches as close as possible too your new one. Then do a difference compare with a text editor.

http://www.vim.org/

This editor has a biult in diffierence compare right in explorer just select two file and right click.

[neocount73]

WOW! Now that's a helpful little application! Thank you. (Do you have any other apps like this in your bag of tricks? [wrings hands greedily]) Unfortunatly, since our Center is in a constant state of crunch time I only have today to fix this problem, and it's allready half over, or I'll have to key each wheel the hard way. If I do find the problem in time I WILL post what it was for closure's sake. wish me luck.

[NigelH]

Given your time crunch, I'd say that the best course would be to re-install LW8.0.1 so you can get back to the last known configuration in which the scene actually worked. Sure, it's a pain, but likely faster than trying to troubleshoot what is most likely a bug. I think I can say that, because I'm experiencing a similar situation in that some expressions that worked fine in 8.0.1 no longer work in 8.2 (while others work just fine. Rather than trying to break down why some work and some don't, it just seems faster to down-grade to 8.0.1 where they all worked.

Hopefully, it will be worked out in the next version.