Maya Station

skin weight normalization in Maya 2011

The skin weights normalization has been updated in Maya 2011, there is a new and improved skin weight normalization, called post normalization.  You can change the normalization settings by using the drop down menu in the Paint Skin Weights tools, it lets you set how you want your weights normalized.  The interactive normalization setting is the same as before, while the post normalization gives you improved results.  So to use the new normalization, the workflow would be do your weighting and then to use the Skin -> Edit Smooth Skin -> Normalize weights.

Instance your LOD groups

Ever tried instancing an LOD group? Well, you'll get some unexpected results if you use the Duplicate Special > Instance option (which would seem to be the way to go)....your instanced LODs will swap at the same time regardless of how far they are from the camera. In fact, they all seem to ape the original LOD group...

Namespaces without referencing

When trying to organize large production files, it is a good idea to use namespaces.   They are easy to set up and can be used without referencing.   If you want to add a namespace to some or all the nodes in Maya you will need to create the name space and then rename the objects to use it. 

So for example I have an object called "sphere" in my scene:

        namespace -add "one";       //will add the namespace to the scene
        rename "sphere" "one:sphere";      //will rename the sphere  

This will do the trick to add the sphere in that namespace.  If you want to change it , you can once again use the rename command to rename it to another namespace.

To keep things organize it’s also very useful to be able to list the available namespace in a current scene.  For this you can use :

        namespaceInfo -lon;

...and off course with the magic of FBX these namespace will get carried to other apps, like Motion Builder, Mudbox. 

how to save user added attributes to a preset

The transform presets are saved in the presets directory, in the application folder.  For example Users/Documents/Maya/2011/presets/attrPresets.   Once you have a preset created through the UI, the transform preset will be saved there automatically.

When you save the presets with user added attributes through the UI, the mel script will list them, but will not actually add them since this is just a MEL script that blends the attributes.   You can add the attributes in it and they will be loaded next time you use the preset.

So for example:

startAttrPreset ("transform")

addAttr -ln myNewAttribute;

blendAttr "myNewAttribute" 0;

The newly added attributes are then available next time you use the presets.

exporting with FBX

When exporting a character rig using the latest version of the FBX plug-in, it is important that none of the geometry is assigned to a mental ray shader. If so, this will cause Maya to crash.

 

Make sure all the geometry is assigned to Maya shaders first before exporting.

 

Autodesk has placed this product issue on development's product modification schedule.

remove reference edits

 If you have made changes to your reference file which has then caused incorrect results, For example making changes to an expression then saving the reference file causes you to lose your expression information; simply reloading the reference file will not be enough to get the original data back.  

You will need to remove the wrong edits.   In order to do this you need to unload your reference from the Reference Editor, and then go to Reference Editor ->List Reference Edits.   In the window that pops up select the wrong edits and click on Remove Selected Edits.  Once this is done you can Reload you reference, through the reference editor.

Use an object's world space position for Set Driven Key.

Every DAG object in Maya knows about its own position in world space. This information is not immediately visible through either the Attribute Editor or the Channel Box, but this quick trick will show how to access the world space transformations of a DAG object, and connect the data to keyable atributes on your object.

How can you constrain an object to vertices and keep rotation

There is a two step process needed to make this work. For this solution I will be using a bird's nest as the object that must be constrained to a tree branch.

 Part 1

1. The tree is one complete mesh. Select a few faces along a length of the branch that the nest will be sitting on.
2. Now extract the selected faces “mesh>extract” This will create a new mesh while maintaining the trees animation history. History is very important!
3. Now select the nest and place it in its spot.
4. Select the newly extracted mesh and shift select the nest and now apply a normals constraint with [Animation] Constrain->Normal
5. If you playback the animation you will see the nest rotate but not follow.

Part 2

This will involve an expression that tells the nest to follow a vertex on the branch.

1. In component mode select a vert that the nest will follow. Make note of the vert number in the channel box. (e.g. 4936)
2. Now select the nest and apply an expression by right clicking on one of the translation attributes in the channel box.
3. Now apply this expression in the bottom field. You will need to change the “birchSpringHeavy1Main” to whatever mesh you want the

nest to follow and change the vtx number to match your vertex number. Finally change to “pCube1” to match your nest name.

float $arrayOfFloats[]=`pointPosition birchSpringHeavy1Main.vtx[2231]`; 
pCube1.translateX = $arrayOfFloats[0]; 
pCube1.translateY = $arrayOfFloats[1]; 
pCube1.translateZ = $arrayOfFloats[2];

Create expression and everything should now be working!

Thanks to Nelson Cruz for providing this tip

In praise of the Geometry constraint, pt 2: a better point constraint?

The Geometry constraint is designed to constrain the position of object A to the surface of object B. Now what happens if you converge all of B's vertices to the same point in 3d space?

You get a point constraint.

Invoke the Expression Editor from the Channel Box

If you're looking to open the Expression Editor from within the Channel Box, you will find that in Maya 2009 it is no longer listed in the menu that appears when you RMB over a highlighted attribute.