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Otterman
12-08-2010, 10:24 AM
Hi wavers. I need some help from the community. I'm hoping it's a relatively easy one to answer but it's gottn me stumped.

I have a few toothed cogs (different sizes) that need to mesh. What's the best approach to do this in LW? I need some cleaver script or something that will do or the hard work for me....keyframing and fudging it by eye isn't an option. They are simple coggs adjacent to eachother, just different number of teeth and of course circumferences.

Any ideas?

nickdigital
12-08-2010, 11:26 AM
Have you looked into Relativity?

I believe the gear ratio is a formula. You could do this via expressions.
http://science.howstuffworks.com/transport/engines-equipment/gear-ratio1.htm

Otterman
12-08-2010, 11:54 AM
Relativity-eeik! That's not so user friendly-it never plays well. I'm thinking a simple expression would do the trick but that's one area of lightwave I shy away from. I'm just need to fathom it out. Good Pinter with the ratio thing...now how do I apply the math? And where? Do you know of any tutorial that might give me a heads up?

nickdigital
12-08-2010, 12:03 PM
In the Graph Editor go to the Expressions tab and hit the Builder button. That'll help walk you through the process.

What you probably wanna do is select Channel as an input.

Once you build the expression you'll wanna clean it up so only the expression is in the text field. From there you can adjust the math to what you want.

Using the 2:1 ratio as an example my expression looked like this on a test I just did:
([Cogs:Cog1.Rotation.B] * -2)

It reads as ([Model:ModelLayerName.Channel] [insert your custom math here])

nickdigital
12-08-2010, 12:09 PM
Try here for expressions tutorials.
http://members.shaw.ca/lightwavetutorials/motion.htm#Expressions

If you're looking for a tutorial video you could try the one on this page:
http://www.liberty3d.com/store/training/lightwave/?product_page=4

Otterman
12-08-2010, 12:22 PM
Super-exactly the kick start I need. Your a gentleman. I will have a stab at it in Tje morning when I get to work

Top banana!

gordonrobb
12-08-2010, 12:50 PM
Instead of expressions just apply Follower on the rotation channel of your gear. Point to to the first gears rotation channel and put the right number in the field for percentage. (I think this is as simple as divide the diameter of the first gear, by the diameter of the second and pu that number. if the first gear is bigger the number will be less than 1, I it is smaller it will be more than 1) no need for expressions.