Use Set_expression From Tcl Proc

[bjorke]

I want to create some tcl proc for assign some expression to any nodes - knobs

By set_expression {xxxx} I always have this message - "Can't set an expression here"

How i can setup current knob by name for this?

May be some one.. Can give me some examples of usage set_expression or some similar for set expression to knobs ?

[bjorke]

I find some useful script like example for set expression...
It is - expression manager 0.0.0 - http://www.fxshare.com/nuke/downloads/tcl\_scripts/4126.html

Line 62 NOT work and give me error message from nuke
(tested in nuke 4.7.2 + update option in script is on)

#comment line 62
#knob $cur_knob "\"$X_Out\""

#add this...
set CurKnob [lindex [split $cur_knob "."] 1]
eval "knob $CurNode.$CurKnob {$X_Out}"

[user_deleted]

It seems like there has been a slight change to knob names since pre 4.6 versions which causes this to break.
Array knobs have an extra index (i.e. translate.0 and translate.1 for x and y respectively) which is picked up in the analyzing part to make sure that x and y values are looked at separately but now seem to break the re-assignment bit when the knob is locked to one value for both.

The way you're suggesting is a bit dangerous as you're always removing whatever index appears after the first dot therefore assigning y and z values to x leaving y and z un-assigned.

I'll look into it and post an update soon.

thanks for pointing it out.

frank

[user_deleted]

I've updated the Expression Manager to fix a couple of bugs:
http://www.fxshare.com/nuke/downloads/tcl\_...nager-4126.html

thanks again for pointing it out to me.

Konstantin, to come back to your original questions:

By set_expression {xxxx} I always have this message - "Can't set an expression here"
How i can setup current knob by name for this?
May be some one.. Can give me some examples of usage set_expression or some similar for set expression to knobs ? smile.gif

try something like:

CODE
in {set_expression }

example:
CODE
in Blur1.size {set_expression {frame*2}}

you can also just use the knob command but make sure to use curly braces :
CODE
knob Blur1.size {frame*2}

if you're assigning different x/y values to an array knob you will have to assign the entire knob like this using an extra set of curlies to bracket the list of fields you are assigning to:
CODE
knob Blur1.size {{frame*2} {frame*3}}

this is where the set_expression command seems to work nicer as it lets you assign values to single fields not just entire knobs:
CODE
in Transform1.translate.y {set_expression {frame*2}}

hope this helps.

cheers,
frank

[bjorke]

I use yours knowledge for Nuke bake expression script: get selected nodes (get exrp. knobs in array ( get values sampled by time to array (setup empty expression + and set array keys ) ))

CODE
in $cur_knob {set_expression curve}

I grab some big chunk from yours script Big thanks, all work perfect for me !!!

P.S: NDK "Nuke TCL comands" help - is very worst thing.... One big page + w/o (exact description + examples + search)

[user_deleted]

glad it helps.

P.S: NDK "Nuke TCL comands" help - is very worst thing.... One big page + w/o (exact description + examples + search)

That page along with the general tcl commands page is pretty much all you need to get into it but I agree it would be nice to have a few practical examples attached.