Expression's Problem

[MCronin]

Is there any particular reason why you aren't just setting the limit using the translate limits information attribute? You can tie it to your custom attribute.

[kpalazov]

The reason is that I don't know about it thankyou for sharing your experiences I have a look in to what you have mentioned.
thanks..if anyone else has any comments on my expression I would be greatlful.

thanks again

Kiril

[playmesumch00ns]

expressions do totally take over your channels. This sort of expression is only really useful when you've got say an IK foot that you want never to go below the ground plane, otherwise you just keyframe your thing to not go below a certain level, non?

Try this. Make an IK leg, then put that exact expression on the heel joint (NOT the IK handle) et voila, it works. From what I gather you are trying to do something like this:

if (myobject.ty < mycustomattr ) myobject.ty = mycustomattr;

It's worth noting that you want to actually set the translate value to the desired level rather than adding some arbitrary number. You can't guarantee how far below that value your object will be when the expression samples it: it may be 0.1, 0.001 or 100! This will cause the object to jump around.

[kpalazov]

playmesumch00ns thanks very much mate what am actually trying to do:
I have a cylinder all rigged- it jumps around and does all kinds of things like that what I wanted to do is make a base which I can move it with . For convenience I wanted to place this expresion on the manipulator grouped with body so that I would not have to worry about constantly going to the attribute panel and and setting translation y to zero, plus for learning sake:)
I will have another look with your expression. Thankyou verymuch for you insight most appriciated.

ALso I wanted to ask, I had a look at the translate limits information attribute but it seems that its only for bones??

thanks again

take care

Kiril

[MCronin]

Any node in Maya that can be translated, rotated or scaled has limit information attributes. For instance, create a locator, go to the attribute panel, click the first tab (locator1, or whatever) go to Limit Information->Translate, and click the checkbox between to Trans Lim Y and the Min fields. Set the now active field to 0. Now you can move the locator all you want, but it will not go below 0 in Worldspace. You can create a custom attribute with an expression, or use a script to determine where your floor is, and feed the result into this limit to prevent a node from dropping below a point in worldspace.

[kpalazov]

Thankyou very very much I am such a fool not to have noticed this , right it front of me dooo:)!

I figured out how to connect an expression to the limit so everything is running exactly to plan.

thanks again

take care

Kiril

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