Around the Corner

Light Draw Override in Viewport 2.0

If you use MPxDrawOverride class to override the draw of your custom locator class, you will have to register the draw override as below: static MString drawdb("drawdb/geometry/light/customLight"); static MString sDrawRegistrantId("customLightDraw"); plugin.registerNode("customLight", customLightNode::m_id, customLightNode::creator, customLightNode::initialize, MPxNode::kLocatorNode, &drawdb); MHWRender::MDrawRegistry::registerDrawOverrideCreator(drawdb, sDrawRegistrantId, MCustomLightDrawOverride::Creator); However, if you want your locator to be classified as light with the same drawdb as above, Maya won't treat your locator as light, because the above drawdb string is applicable only for geometry override not for light. The node will... Read more →

Maya 2016, Parallel Evaluation and New API’s

When you start Maya 2016, you will automatically be in parallel evaluation mode. This is new default evaluation mode, replacing the legacy DG-based evaluation. Maya 2016 uses the DG’s dirty propagation mechanism to build the Evaluation Graph(EG). Dirty propagation is the process of walking through the DG, from animation curves to renderable objects, and marking attributes on DG nodes as needing to be re-evaluated (i.e., dirty). Unlike previous version of Maya that propagated dirty on every frame, Maya 2016 disables... Read more →

Registering a plug-in to work with Maya archive

To add external dependencies to the archive created by Maya with "File" --> "Archive Scene", a plug-in developer needs to implement the MPxNode::getFilesToArchive() method. The documentation is [here](http://help.autodesk.com/view/MAYAUL/2016/ENU/?guid=__cpp_ref_class_m_px_node_html). This will add the plug-in node's external dependencies to the archive. While you are at it, you can add any file paths to Maya’s File Path Editor UI using this command: filePathEditor –registerType "myNode1.filePath" –typeLabel "Custom" If you wish to add the external dependencies to metadata in the Maya file itself, use... Read more →

How to decide if an input attribute is changed or its value is not valid any more?

When you are working with Dependency Graph and custom node, sometimes in compute() function call you want to check if an input attribute is changed or its value is still up to date. At first glance, the most straightforward approach to tackle this down is to use MDataBlock::isClean(). This function will return false if your attribute value is not valid any more, which means you will need to either retrieve or recalculate a new value on this attribute. However this... Read more →

How to check for error for MDataHandle::child()?

First if you're using the MPlug version, it cannot fail but if you're using the MObject version and if it fails, it would return an empty MDataHandle. I.e. equivalent to: MDataHandle tmp ; and its type() method should return you kInvalid. Unfortunately, if the child attribute is also a compound attribute, type() would also return kInvalid. So what's up? in order to keep MDataHandle operations fast in Maya, minimal checking is performed, which for most methods means no checking at... Read more →

Maya Node Editor and Attributes

The Node Editor takes a number of features that were previously divided between Maya's Hypershade, the Hypergraph and the Connection Editor, and merges them into a single user-friendly workspace. The Node Editor gives us a much simpler way of making advanced connections between any nodes or attributes in your Maya scene. With the Node Editor you can graph, pin and clear nodes from the Node Editor... create nodes directly within the Node Editor, create / connect node attributes... But while... Read more →

Support Soft Selection with custom MPxComponentShape

MPxComponentShape allows the implementation of new user-defined shapes using components, however all the UI related feature (such as selection/drawing) has to be implemented with another class MPxSurfaceShapeUI. In the MPxSurfaceShapeUI class, there are select() and draw() functions you need to implement for your custom shape. The Maya devkit has 2 examples that demonstrates how to use this class: apiMeshShape and apiSimpleShape. The apiSimpleShape shows to how to use MPxSurfaceShapeUI to work with MPxComponentShape to achieve component selection and drawing. But... Read more →

Paintable Attributes on Custom Deformer Node

To create a custom deformer node in Maya, you would need to derive from MPxDeformerNode, and the documentation says to not override the compute() method unless required since the deform() method is called by the MPxDeformerNode's compute() method. There is few exception to that recommendation. Exceptions are namely: Your node's deformation algorithm depends on the geometry type, which is not available in the deform() method, Your node's deformation algorithm requires computing all of the output geometries simultaneously, So if you... Read more →

Using the Microsoft Kinect SDK to bring a basic point cloud into Maya

Today’s post presents a very basic implementation of a point cloud – essentially equivalent to the code in this previous post – which makes use of the Microsoft Kinect SDK to bring the Kinect color image on a Maya image plan live. While for an image it was pretty straight forward to take the Kinect color image and use the Maya API MImage class to read that image. This time we are interested to get the depth information out of... Read more →

Initial fooling around with Kinect and Maya

In a previous post, we talked about the Maya device API and mentioned I may try and write a device plug-in for the Kinect. There is few things I want to try with the Kinect: Some simple model capture using the Kinect’s RGB-D camera Generate a point cloud Simple gesture-based control And finally using the latest Kinect Fusion SDK create object meshes The first seemed a fun approach to test out the Kinect interface, although ultimately the currently-available precision (the... Read more →

Can my custom node survive to delete

When you use MDagModifier to delete the last shape under a transform, the transform is automatically deleted as well. That is the normal Maya behavior. It helps to keep the scene clear of orphaned transforms and is consistent with MDagModifier::createNode(), which will automatically create a parent if none is specified when creating the node. However, you need to know that MDagModifier::reparentNode() would not delete empty parents when that happens. And the 'delete' command doesn't behave the same way since it... Read more →

No 64bit integer attribute in Maya? no way!

Ok, but where is it? If you take a look to the Maya API documentation you will find a lot of things about 64b support, but the only classes specific to 64b will be: the MUint64Array which is an array of MUint64 data type, the MFnUInt64ArrayData class which allows the creation and manipulation of the MUint64Array objects for use in the dependency graph when the MDataHandle::type() method returns kUInt64Array. The MFnUInt64ArrayData / MUint64Array / MUint64 classes are present in the... Read more →

Custom Shapes in the Maya API

A user-defined surface shape is one of the most complex types of nodes that can be implemented within Maya. A number of supporting classes are required, and a number of virtual methods must be properly implemented to get your class working right with the various parts of Maya. The goal of this article is to break down the process of creating the shape into manageable chunks, and to provide details of each step of the process so that you can... Read more →

Autodesk Maya 2013 Extension Release (codename “Barbaretta”)

With the announcement made at SIGGRAPH 2012, there is something important to note about the Extension release! Unlike past releases, this one will not be binary compatible with its major release. In the past, a hotfix, Service Pack, and Extension release were binary compatible with their respective major release; that's not the case this time! Here is an example to illustrate what this means: The Maya 2012 Extension release is binary compatible with the Maya 2012 major release, which means... Read more →

Maya API thread safe?

In general it is not safe to assume any Maya API is threadsafe if it is not documented as being so. There can be internal caching or state being set, meaning functions that may seem threadsafe are in fact not. An example is MFnMesh::getVertexNormal(). These normals are evaluated lazily, meaning the first call to this function may trigger a full recompute of all normals, so two calls simultaneously may have bad consequences. One clunky way around this is to do... Read more →

a Mathematical DG Node

Many of you probably knows about the sineNode available in the Maya devkit written in C++ and/or Python. This example is very useful if you interested running the sin() function. But there is several limitations which make this example a bit dry. First, it is just the sin() function and with this approach it means you would need to create as many 'math' node you want mathematical functions. Second, it has one input and one output parameter only, so it... Read more →

Maya Fluid Shader

Today, we will talk about the dedicated Maya fluid shader workflow. Usually people who has their own fluid shader wants to mimic the Maya one, so we review in details what one needs to do. The general flow of the fluid shading computation is: Compute the desired grid values for a point within the volume for example density or temperature the value at the point is determined by the grid values interpolated using the desired interpolation method (described in the... Read more →

Dirtying a Maya MPlug for Array Attribute

In Maya API, there is no way to explicitly set a plug dirty. However there is a MEL command "dgdirty()" to do exactly that. The MEL command takes the plug name and optionally the index if the plug is an array. I.e. 'dgdirty myNode.myattribute[1]'. In this example you set dirty the second element of your array plug. There is also a MEL command to determine is a plug is dirty or not - that command is simply named "isDirty()". From... Read more →