MRampAttribute

Hey, thanks for posting this. I’m doing research on wire deformers and remembered seeing someone else use a curve like this for shaping, which is exactly what I’d like to do.

Excellent stuff, gave me a nice shortcut around doing too much thinking today. Thanks Chad.

I would add this little snippet of handy info :

When using api ramps with nodes, it’s a good plan to initialize the ramps with single entries to avoid errors when using the Attribute Editor.

Oddly enough this accomplished via the AEtemplate, as in the following code tweak to your AEtemplate ( the extra code runs once & not after a user has added their own ramp entries [seemingly]):

global proc AErampDeformerTemplate( string $nodeName )
{
editorTemplate -beginScrollLayout;

editorTemplate -beginLayout “Ramp Deformer Attributes” -collapse 0;
AEaddRampControl( $nodeName + “.curveRamp” );
AEaddRampControl( $nodeName + “.colorRamp” );
editorTemplate -endLayout;

editorTemplate -addExtraControls;
editorTemplate -endScrollLayout;

// — With Ramps, we have to add some default values
// to avoid an error when displaying them in the Attribute Editor :

setAttr ($nodeName + “.curveRamp[0].curveRamp_FloatValue”) 1.0;
setAttr ($nodeName + “.curveRamp[0].curveRamp_Position”) 0.0;
setAttr ($nodeName + “.curveRamp[0].curveRamp_Interp”) 1;

setAttr ($nodeName + “.colorRamp[0].colorRamp_Color”) -type double3 1 1 1;
setAttr ($nodeName + “.colorRamp[0].colorRamp_Position”) 0.0;
setAttr ($nodeName + “.colorRamp[0].colorRamp_Interp”) 1;
}

Nice example, thanks!

NTaylor, you should also check if some value already presents in the ramp (smth like `getAttr -silent -size ($nodeName+”.”+”curveRamp”` == 0) or it will override stored value.

Andrey, You’re entirely correct about my suggestion leading to the overriding of values. Bad NTaylor. Bad.

Now that I finally have a chance to test this all out properly, I’ve run into the problem you’ve outlined. My values are indeed being overridden.

I’ve tried tinkering with your code, but I always get a size of 1 when running the code you suggested : My ramps *always* have an entry [0] just after createNode has been executed. This is also regardless of the value stored at index [0], so checking against a presumed default value is tricky [impossible].

Which means that I cant seem to find a MEL/AE solution for safely setting default ramp values :

I can wrap the createNode command within a MEL function that sets those default values, but it’d be nicer to be able to simply default initial ramp values so that they’re ‘correct’ if a user makes the node via createNode as well.

With that in mind I’ve tinkered a fair bit and found an ideal solution (via the API) : set initial ramp values from within the ::postConstructor() and set NO values in the AETemplate at all. Ideal.

===Post Constructor===

void YourNode::postConstructor()
{
MStatus status;

postConstructor_initialise_ramp_curve( YourNode::thisMObject(), aYourRamp, 0, 0.0f, 1.0f, 1 );

}

===postConstructor_initialise_ramp_curve===

MStatus postConstructor_initialise_ramp_curve( MObject& parentNode, MObject& rampObj, int index, float position, float value, int interpolation)
{
MStatus status;

MPlug rampPlug( parentNode, rampObj );

MPlug elementPlug = rampPlug.elementByLogicalIndex( index, &status );

MPlug positionPlug = elementPlug.child(0, &status);
status = positionPlug.setFloat(position);

MPlug valuePlug = elementPlug.child(1);
status = valuePlug.setFloat(value);

MPlug interpPlug = elementPlug.child(2);
interpPlug.setInt(interpolation);

return MS::kSuccess;
}

===AE TEMPLATE===
global proc AErampDeformerTemplate( string $nodeName )
{
editorTemplate -beginScrollLayout;
editorTemplate -beginLayout “Ramp Deformer Attributes” -collapse 0;
AEaddRampControl( $nodeName + “.curveRamp” );
AEaddRampControl( $nodeName + “.colorRamp” );
editorTemplate -endLayout;
editorTemplate -addExtraControls;
editorTemplate -endScrollLayout;
}

____________________________________
(Apologies for the formatting)

The above use of the PostConstructor works great. All Ramps can be built with default values and no errors are reported in maya with the original, simpler, AETemplate.

You can call the postConstructor_initialise_ramp_curve() more than once to set more than 1 default entry/position/value for a ramp

This can be easily extended to handle color ramps as well :

MStatus postConstructor_initialise_color_curve( MObject& parentNode, MObject& rampObj, int index, float position, MColor value, int interpolation )

{
MStatus status;

MPlug rampPlug( parentNode, rampObj );

MPlug elementPlug = rampPlug.elementByLogicalIndex( index, &status );

MPlug positionPlug = elementPlug.child(0, &status);
status = positionPlug.setFloat(position);

MPlug valuePlug = elementPlug.child(1);
status = valuePlug.child(0).setFloat(value.r);
status = valuePlug.child(1).setFloat(value.g);
status = valuePlug.child(2).setFloat(value.b);

MPlug interpPlug = elementPlug.child(2);
interpPlug.setInt(interpolation);

return MS::kSuccess;
}

________________________________________
I’ve left out a tonne of MStatus error checkling/trapping in the above code to reduce it a bit.