MAXScript Language Improvements in 3ds Max 7

The following is a description of internal changes and "tweaks" to the MAXScript language in 3ds Max 7. Other than the "What is new..." topic, these changes do not implement new objects, classes, methods or interfaces, but change the way MAXScript works internally. Usually these changes either improve performance or simplify programming.

Node Access Improvements

new.gif A node name cache has been implemented. It is used by MAXScript to resolve pathnames (like $box01) to scene nodes. This optimization primarily comes into play with script controllers that use pathnames. In a scene with 5001 nodes and a script controller that references the 5001'th node by name twice, the time for 10000 evaluations of the script controller went from 147 seconds to 1.6 seconds.

A new checkbox was added to the MAXScript tab of the Preference dialog: Use Fast Node Name Lookup. When on, scene node names are cached by MAXScript, resulting in significantly faster resolution of non-wildcard pathname values (i.e., $box01) to node values. When off, the scene nodes are enumerated looking for a scene node name that matches the pathname.


new.gif An optimization was introduced in 3ds Max 7 that checks to see if a node has already been invalidated before sending out notifications to it's dependents that it has been changed. It speeds up complex rigs, especially those that involve the new expose transform helper. It is controlled by the preferences.InvalidateTMOpt System Global variable. When set to true, the optimization is enabled and multiple notifications will not be sent out. When set to false, the animation system behaves as in 3ds Max 6 and earlier. It is enabled by default.


new.gif The MakeNameUnique function was changed to use an std::set rather than an a Tab<int>. This reduced the time for creating 2500 nodes of the same type from 145 seconds to 71 seconds. If the nodes are renamed as they are being created, time for creating 2500 nodes reduced from 47 seconds to 11 seconds.


new.gif The getNodeByName function has been significantly enhanced.

Custom Attributes

new.gif refs.dependson now returns the Custom Attributes of an object. In versions prior 3ds Max 7, Custom Attributes were not considered by this method as technically they are not dependent on the object.


new.gif classOf will return the custom attribute definition (MSCustAttribDef) if passed a scripted custom attribute instance. In previous releases, it was returning a MAXClass value.


new.gif The visible name of the MAXCustAttrib class was changed from CustAttrib to MAXCustAttrib. Now you can use: 'CustAttrib.classes' to access the custom attribute classes, and test the superclass of custom attributes against CustAttrib.


new.gif Added .isPB2Based as a property of custom attribute definition MSCustAttribDef. Already a property of MAXClass and MSPluginClass.

new.gif Added .isMSPluginClass as a read-only property of custom attribute definition MSCustAttribDef, MAXClass, and MSPluginClass. MSPluginClass derives from MAXClass, and MSCustAttribDef derives from MSPluginClass. Property is true if the class is a MSPluginClass or MSCustAttribDef. See also the previously defined isMSPluginClass() method.

new.gif Added .isMSCustAttribClass as a read-only property of custom attribute definition MSCustAttribDef, MAXClass, and MSPluginClass. Property is true if the class is a MSCustAttribDef. See also the previously defined isMSCustAttribClass() method.



new.gif In versions prior 3ds Max 7, the user was responsible for re-initializing the mesh to make it valid before calling update. However, most users would not know everything that needs to be done to re-initialize the mesh properly. For this reason, the re-initializing is done when setting the .numfaces or calling the setNumFaces method.

when Change Handler

new.gif A when parameters obj change handler now also picks up topological and geometry changes.

The reason for the previous behavior was the following: if obj was a node, the parameter change message from a changing parameter in most modifiers (including Attribute Holder) was being changed by the ModApp to a geometry change message.

Function Publishing System methods NULL values

new.gif For FPS methods/properties that take a Material, RefTarg, INode, Object, or Control values, 'undefined' is an accepted value and is converted to NULL

getMAXFileObjectNames Strings

new.gif getMAXFileObjectNames now returns an array of string values, rather than an array of name values. The object names used by mergeMaxFile are case sensitive, and name values are not guaranteed to maintain the case of the string they wrap. See 3ds Max File Loading and Saving

Macro Recorder

new.gif The Macro Recorder Path Analyzer has been changed to ignore references that are either DeleteReference restore objects or MAXScript MAXWrapper values. In the past, if the Path Analyzer found one of these references before a reference into the scene, no macro recorder output was generated.

InsertItem for MAXPB2ArrayParam Values

new.gif The insertItem method has been extended to work with MAXPB2ArrayParam values:


plugin helper testObj





parameters main


mtltab type:#materialtab tabsizevariable:true




t1 = testObj parent:b1

append tabtest.materialTab (standard name:"1")

append tabtest.materialTab (standard name:"2")

append tabtest.materialTab (standard name:"3")

insertItem (standard name:"4") tabtest.materialTab 3


Scripted Plugins

new.gif The testing of the 'extends' class type in scripted plugins has been fixed, so a scripted plugin can now extend a scripted plugin.


new.gif The simpleMod 'map' event handler call is now explicitly disabled if no map event handler is defined. This leads to no real execution speed increase, the first call to the map event handler would have returned a non-Point3 value that would result in the event handler being disabled anyway.


new.gif A remap keyword argument was added to scripted plug-in and scripted custom attribute definitions.

This keyword allows parameter names in the definitions to be changed when updating existing definitions. The keyword takes as an argument a 2 element array, where each element contains an array of string literal or name values. The size of the 2 arrays must be the same.

The names in the first array are the existing parameter names, the names in the second array are the new parameter names.

As parameter names are read in while migrating existing plugin instances, the parameter names are searched for in the first array. If the name is found, the data associated with that parameter is moved to the parameter name in the corresponding location in the second array.

If a parameter name is not found in the first array, the parameter name is not remapped. If the parameter name in the second array does not match a parameter name in the new definition, the parameter data is not moved to the new definition.

String to Boolean Coercion

new.gif Coercion of String to Boolean has been added.

Valid string values (case insensitive) for this coercion are:

"on" as booleanClass --> true

"off" as booleanClass --> false

"true" as booleanClass --> true

"false" as booleanClass --> false


All other string values will result in a runtime error

Array to String Coercion

new.gif Introduced a MAXScript variable options.printAllElements and a context with printAllElements <bool> do <expr> for controlling whether the complete Array, MeshSelection, BigMatrix, and BigMatrixRowArray is printed or coerced to string, or just the first 20 elements.

Name Values

new.gif A copy method was defined for name values. The method returns the same name value. This is needed to support deep copying of arrays in a clean way.

SubAnim Values

new.gif New read-only properties .parent and .index have been added to subAnim values. The parent is the true object owning the subAnim, and the index is the subAnim index within that object.


The true object owning the subAnim can be different than what was originally specified when creating the subAnim, and MAXScript automatically hides certain types of subAnims, automatically promoting the subAnims within them.

For example:


sa = s.baseobject[0]






--The actual owner of the Radius subAnim is the sphere's parameter block.

User Interface Controls

new.gif The .text property is now equivalent to the .caption property for all rollout controls that do not define .text separately (for example, the EditText control already has a .text property). Setting a label's text is the same as setting a label's caption. In previous releases, setting the text would not update the UI, but would update the internal .caption value.


new.gif The calculation of the construction height of comboBox and dropdownlist was improved. The mininum value of the height parameter of comboBox, dropdownlist and listBox controls is now clamped to 1.


new.gif #worldUnits is now accepted as a type of Slider, and is equivalent to a type of #float


new.gif Spinner controls with align:#left were not being positioned correctly. Changing the spinner width would move the spinner right or left, with part of the spinner frequently outside the rollout width. This has been fixed so that left aligned spinner controls stay put on the left as width changes.


new.gif The Group UI control has been fixed to handle controls within the group that use the across: parameter. The bottom of the group is now below the largest control within the group, rather than below the last control within the group.

For Example:

rollout test "test"


group "Test Group"


radiobuttons rb_Test labels:#("AA","BB") columns:1 align:#left across:2

label lb_test "Test Label:" align:#left offset:[40,0]



createdialog test width:329


In 3ds Max 6 and earlier versions, the above would result in


In 3ds Max 7, the result looks like



new.gif Rollout event handlers are now accessible as properties of the rollout. For example, <rollout>.open() will call the open handler of the rollout.

Controlling Program Flow

new.gif Fix for continue while mapping across node objectsets.

For example:


b=box();b2=box parent:b

for o in objects do (print; continue)

for o in $* do (print; continue)


would print only Box01, not Box02 in 3ds Max 6 and earlier.

Now it prints both.

Getting the Current Exception

new.gif New getCurrentException() method returns the text of the current exception in conjunction with a catch() statement.

Miscellaneous Tweaks

new.gif no_max_maker was fixed to return MAXNode values instead of MAXRefTarg values for nodes.


new.gif If the first argument of getTransformAxis is the value undefined instead of a node, the viewport common axis is returned instead.

If the Coordinate System Center (returned by getCoordCenter()) is #local or the Ref Coord System (returned by getRefCoordSys()) is #local, #parent, or #gimbal, the last calculated common axis is returned.


See also

What was New in MAXScript in 3ds Max 7

Documentation Changes in 3ds Max 7

Documentation Updates after 3ds Max 7 Release


Documentation Changes in 3ds Max 6

Documentation Changes in Particle Flow Update