topic Re: Ramp attribute crash in compound attribute in Maya Programming Forum

Ramp attribute crash in compound attribute

peter.kalmar — Mon, 30 Aug 2021 13:47:36 GMT

Hey,

I am making a C++ plugin and I have a weird crash when using MRampAttributes.

I have an MPxNode, which has a child array of compound attributes.
When I try to add one or more ramp attributes as a child to this compound, Maya crashes when loading the plugin without providing a stack-trace in the Output window.

So the desired structure would be:
node.childCompoundArray[0].rampAttribute

Sometimes the plugin works with one ramp attribute added, but crashes when I add another one next to the first.

(node.childCompoundArray[0].rampAttributeB)

Any ideas why this may happen?

Does Maya prohibit using ramp attributes as child attributes / in an array?

Or can this be the fault of having multiple ramp attributes next to each other?

I have not found anything in the official documentation on this matter.

I am using the Maya 2019 API.

Thanks in advance,

Peter

Re: Ramp attribute crash in compound attribute

jmreinhart — Mon, 30 Aug 2021 22:45:23 GMT

Could you please post a code sample that reproduces your issue?

Re: Ramp attribute crash in compound attribute

peter.kalmar — Tue, 31 Aug 2021 09:11:03 GMT

Sure!

// A static function that is called by the node's initializer. // We pass the references to the static attribute MObjects. // This function is used in several nodes to add the commonly used attributes. // Unrelated code was omitted. // All other attributes are working correctly (numeric, typed, compound, matrix etc.) void SamplerUtils::createCommonAttributes( MObject& sModifiers, MObject& sModifierEnabled, MObject& sModifierScaleRamp, MObject& sModifierScaleFalloff, MObject& sModifierDensityRamp, MObject& sModifierDensityFalloff, ) { MStatus status; MFnNumericAttribute nAttr; MFnCompoundAttribute cAttr; sModifierEnabled = nAttr.create("modifierEnabled", "moden", MFnNumericData::kBoolean, 0, &status); CHECK_MSTATUS(status); nAttr.setDefault(true); sModifierScaleFalloff = nAttr.create("modifierScaleFalloff", "modscf", MFnNumericData::kFloat, 10.0f, &status); CHECK_MSTATUS(status); nAttr.setMin(0.0f); nAttr.setDefault(10.0f); nAttr.setSoftMax(30.0f); sModifierDensityFalloff = nAttr.create("modifierDensityFalloff", "moddef", MFnNumericData::kFloat, 10.0f, &status); CHECK_MSTATUS(status); nAttr.setMin(0.0f); nAttr.setDefault(10.0f); nAttr.setSoftMax(30.0f); sModifierScaleRamp = MRampAttribute::createCurveRamp("modifierScaleRamp", "modscr", &status); CHECK_MSTATUS(status); sModifierDensityRamp = MRampAttribute::createCurveRamp("modifierDensityRamp", "modder", &status); CHECK_MSTATUS(status); sModifiers = cAttr.create("modifiers", "mod", &status); CHECK_MSTATUS(status); CHECK_MSTATUS(cAttr.addChild(sModifierEnabled)); // CRASH! // CHECK_MSTATUS(cAttr.addChild(sModifierScaleRamp)); CHECK_MSTATUS(cAttr.addChild(sModifierScaleFalloff)); // CRASH! // CHECK_MSTATUS(cAttr.addChild(sModifierDensityRamp)); CHECK_MSTATUS(cAttr.setArray(true)); CHECK_MSTATUS(MPxNode::addAttribute(sModifiers)); }

If I add the ramp attributes to the node itself, and not as a child in the compound it works - sometimes. Other times it still crashes Maya.

Péter