# Dna Unwind
**URL:** https://forum.highend3d.com/t/dna-unwind/1210
**Category:** Maya
**Tags:** mel
**Created:** [January 10, 2009, 8:00pm UTC](https://forum.highend3d.com/t/dna-unwind/1210 "2009-01-10T20:00:16Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@mindspan](https://forum.highend3d.com/u/mindspan)
#### Post date: [January 10, 2009, 8:00pm UTC](https://forum.highend3d.com/t/dna-unwind/1210/1 "2009-01-10T20:00:16Z")
I am making a strand of dna unwind and attempting to use mel to do it. I have built my DNA with a base and rotated and duplicated it to its spiral shape. I now want to control the rotate y of each (20 individual pairs) with this script.
for ($i=1; $i\<=019; $i++) {
float $rotY = $i \* 0.05;
expression -s ("rotateY = pair020.RotateY \* " + $rotY + ";") -o ("pair" + $i) -ae 1 -uc all;
};
when I run the script I get this error
// Error: Attribute not found or variable missing '$': pair020.RotateY //
// Error: Attribute not found or variable missing '$': rotateY //
Why does this happen as each pair I have has a different rotate Y value in the channel.
Thanks for your help!!!
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### Author:  [@joojaa](https://forum.highend3d.com/u/joojaa)
#### Post date: [January 10, 2009, 8:08pm UTC](https://forum.highend3d.com/t/dna-unwind/1210/2 "2009-01-10T20:08:57Z")
re your objectsnamed pair001 paor002.. or pair01 pair02...
if thsi is your mnaming convention all the apply would be wrong. So the object name after -o must be right for this to work out.
So most likely ("pair" + $i) is just plain wrong. Anyway i would meake his all isnide one expression node.
QUOTE
Why does this happen as each pair I have has a different rotate Y value in the channel.
Thanks for your help!!!
Its a very special kind of syntax error, that happens when the expression is about to be parsed but does not make sense.