Command line pre-render MEL..?

[aaron_johnson]

ok this is a weird one

i'm rendering a series of animations from the command line, each animation is a different pass of the same scene (color, shadow, etc). i have these custom passes setup with shelf buttons, so i can just click a button, save the scene as a new name and render the different files from the command line.

what i would prefer to do, now that i've made the shelf buttons, is not have to save seperate scenes, but just type a variable from the command line that has the effect of clicking on a shelf button before rendering but of course i can't access the shelf button when outside maya.... or can i...?

is there a way i can do this from the command line...? or am i just being too lazy

cheers

[joojaa]

Yes theres aplugin for that. But suprise suprise it can be donbe via mel. All you need is a prerender script that does this. But how to pass messages to the script... well you write the passed argument to a dummy file with >> operator amnd then a & operator for makeing on command line out of this... And it can be batched.

[aaron_johnson]

with pre-render scripts don't you have to first save a scene with them already specified...? if so i need something that works externally from the command line... with maya closed. eg. i want to be able to pass different mel commands to the same scene file... without having to open maya.

its not that Injector plugin is it...? that's also an internal solution.

[joojaa]

No...

The idea is to have a prerender mel call a file wich it the sources thsiway its a external execution, Now thsi file can be exacyted extenrnaly.

Note you dont want to call mayabach as its too slow a solution youd be running maya up 2 times thisway.

Se there must be some mechanism to allwo you to communicate with the extrenal command prompt. Example suppose we have a prerender mel that contains the following statement;

source "c:/temp/test.mel";

okay now it runs mel precs inside that file, now command line can easily overwrite that file with the , had some problems regarding this and mentantalray and creation objects on fly as they didnt get connected to lights, but one can script this.

now call it with a commandline like this

echo mycommand here > c:temptest.mel & render file.ma

ofcourse you can use the mentalray renderer too.. in this manner

[aaron_johnson]

interesting - thanks for the tips - i'll have a play around with it.

[mattias]

Anyone care to explain this a little further? I

[joojaa]

ive evolved this a bit since then to even more confortable way of doing this without any external program. All you need is to write all the layer specific init in a scriptNode (you can do scriptnode sin the expression editor for example, name the appropriately)

then jsyt add a flag -pre "scriptNode -eb yourScriptNodeName;" to your render option.

Theres MR specific layer demo version of this available in my webgarbage bin if you want to looksee. The same works with no problems in software renders (with the exception that the raytracer isnt adjusted to being on and the shadeow ray bias is bonkers, in the demos scene). The reason it uses mr was that at the time i was doing the demo it was for the mf forum!

renderingPassesDemo.zip.

Theres a also some discussion on the render forum that discusses how to get the data from nodes automaticaly to store them in the nodes. And as it is maya has scripts allmost ready for this allready (minor tweaks needed)

Or you can use the rendering pass plugin on this site wichever way you prefeer. My way offecurse needs no plugin and works on all platforms, now all you need is a script to store the differnt settings such as layer/object visibility etc to automate the task of collecting it.