Changing the shading model of an existing material

[goggle]

ya know how if you open a shader up in the Attribute Editor there's that pull down menu where you can change it from one shading model to another (Lambert, Blinn, Phong, Anisotropic, and so on) and it'll keep the attribute connections.

Well I've been trying to figure out how to do that through MEL. I haven't been able to find any reference to it in the manuals. When I look at "echo all commands" it seems that Maya is creating a brand new material, reading the connections from the old one, reconnecting to the new one, and deleting the old one. Makes sense. But AFAIK there is no one single command for that procedure.

I'd really rather not have to re-invent the wheel and go through all those steps manually in my script. So does anyone know of an easy way to accomplish this?

The eventual goal is to turn everything into a Lambert while retaining the Transparency attribute but reconnecting the Color to something else.

Does this make any sense?
Any help or just a push in the right direction would be greatly appreciated.

-James

[jeffd]

I looked at this a little bit, but unfortunately don't have then time right now to totally pull it apart.

It looks as though most of what you need can be figured out by figuring out what is going on in AEshaderTypeNew.mel and replaceNode.mel. It seems that there might be a single procedure in there to call that automates all the rest of that garbage the echo all commands shows is happenning.

Btw, the name of the optionMenuGrp that is the material type drop down box is "typeMenu". And simply editting its value doesn't work since all sorts of new attributes must be created (as well as a whole new node) for your material to truly become a new type.

Good luck.

--JeffD

[shekh]

This is 'almost' copied from AEshaderTypeNew.
This works perfectly, no need to study replaceNode.

    string $old = "lambert2";
    string $new = `createNode blinn`;
    replaceNode $old $new;
    delete $old;

[goggle]

shekh: Thanks, it's working great.

JeffD: AEshaderTypeNew and replaceNode were quite instructive as well.

This is what I wound up with if anyone's interested.

global proc convertToLambert()
{
string $materials[] = ls -materials;
for ( $mat in $materials )
{
string $type = nodeType $mat;
if ($mat != "lambert1")
if ($mat != "shaderGlow1")
if ($type != "particleCloud")
{
string $origMat = $mat;
string $new = createNode lambert;
replaceNode $origMat $new;
delete $origMat;
rename $new $mat;
}
}

}

The reassigning of attribute channels should be a peice of cake after this. I'm trying to automate the setup for a zDepth pass because Maya's default zDepth pretty much sucks.

-James