View Full Version : relativity help, new challenge

09-29-2006, 12:30 PM
I'm on to a new expression:

sin(H(SELF,t)) into the z channel of a null. This raises and lowers the null appropriately when it turns other than that the null drops too low. (y, it's turned in space, my z local is y global)

How do I set a lowest value the null can drop to before just stopping? I can't change the origin of the motion and I need the height to remain where it is as well.



09-29-2006, 12:33 PM
There is a limit button on the main panel. You can set upper and lower limits there. Note that these are abrupt limits.

09-29-2006, 12:36 PM
For a more controllable approach, you can do something like :


This basically says CONDitional to sin(H(SELF,t)) being less than the value set in variable slot A, set my value to A. Otherwise use sin(H(SELF,t))

09-29-2006, 01:15 PM
I omitted that the null has a parent. The parent is rotated (causing the local z to be on the global y). I'm having a unexpected difficulty with the expression, so I wonder if it's a local / parent / global coordinate issue?

Either that or I'm bumbling it up.

Any ideas?


Nope, I have it. Thanks again, Phil!

09-29-2006, 01:24 PM
I'll upload an example. Two seconds.....


That seems to do what you wanted. Let me know if I got the wrong end of the stick :)

09-29-2006, 01:32 PM
Thank you. These little learning episodes make so many things so much easier. I really appreciate it.


09-29-2006, 01:37 PM
No problem. As I said, I *love* Relativity with a passion. It was the first plugin I bought for LW back in '98 or so (from version 0.3 or so) and I have used it in every scene since then. It's second nature by now :D I wish I could say the same for Nodal, but I'm blessed with slow old hardware at the moment, so rendering is a fairly annoying experience ;)

I get irritated with Prem for the inordinate delays (worse than Worley!) in getting new builds of his development plugins, but when they come, they are really worth it :)