Introduction to Maya Programming

1
Introduction to Maya Programming

• Shuen-Huei Guan
• CML, CSIE, National Taiwan University
• 2003/10/7

2
Overview

• Introduction
• Philosophy behind Maya
• Maya programming
• Tutorial exporter
• Assignment

3
Why?

• Maya is everywhere, especially in game / film /
  animation.
• Maya expert Artist Computer Scientist.
• Uncle Sam needs you.

4
Introduction to Alias

• Alias Research, 1983.
• Wavefront Technologies, 1984.
• AliasWavefront under SGI, 1995.
• Alias, 2003.

5
Introduction to Maya

• Released in 1998.
• Rumor has it that
• Implemented by over 200 PhDs.
• Too big s.t. no one knows it well.
• Alias is going bigger.

6
Lets Use Maya

• Basic transformation.
• Selection by object, component.
• Polygonal modeling.
• Mirror.

7
Lecture Outline

• Introduction
• Philosophy behind Maya
• Maya programming
• Tutorial exporter
• Assignment

8
Philosophy behind Maya

• Before being a programmer, be a philosopher
  first.
• Truly, It is ugly. But luckily, it is not that
  ugly as Microsoft things.

9
Philosophy Overview

• Naming Conversion
• Data Structure
• Function Sets

10
Naming Conversion
11
3D Rendering Pipeline

• Static model
• Shading
• Texture
• Animation
• Rendering

12
3D Rendering Pipeline

• Static model
• Shading
• Texture
• Animation
• Rendering

13
3D Rendering Pipeline

• Static model
• Shading
• Texture
• Animation
• Rendering

See test.avi
14
Pipeline Data
Model
Viewpoint of data
Textured Model
Animated Model

15
Pipeline Operators
Polygon Manipulator
Viewpoint of operators
Shader
Animation Curve

16
Structure in Maya

• Node Structure
• Directed Acyclic Graph
• Dependency Graph

17
Node Hierarchy
18
Function Sets

• Objects are hidden as handles (IDs).
• Use Function sets to access objects.

19
Function Sets in Diagram
20
Example Traditional Class

• CMesh poMesh poScene-gtgetMesh(dove)
• poVexArray poMesh-gtgetVexArray()
• iPolyNum poMesh-gtgetPolyNum()
• for (i0 iltPolyNum i)

21
Example Function Sets

• MMesh oMesh oScene.getMesh (dove)
• MFnMesh oMeshFn(oMesh)
• MArray oArray oMeshFn.getVexArray ()
• iPolyNum oMeshFn.getPolyNum ()
• for (i0 iltiPolyNum i)

22
Lecture Outline

• Introduction
• Philosophy behind Maya
• Maya programming
• Tutorial exporter
• Assignment

23
Maya Programming

• 2 choices for Maya programming
• Maya Embedded Language (MEL)
• C API
• Not exclusive to each other.
• Not a set-relationship.

24
Introduction to MEL

• Familiar C-style grammar.
• GUI maker.
• All you do is through MEL.
• Maya DLLs MEL.

25
Lecture Outline

• Introduction
• Philosophy behind Maya
• Maya programming
• Tutorial exporter
• Assignment

26
Tutorial exporter

• Exporter
• Input scene file (.mb/.ma)
• Platform Maya
• Output obj file (.obj)

27
Things you need to know

• Foundation.lib OpenMaya.lib.
• Use Maya wizard to ease life.
• Inherit from MPxFileTranslator.
• Put plug-in in Maya/bin/plug-ins.
• Sample lepTranslator.

28
Exporter

• Traverse all nodes.
• Pick out mesh nodes.
• Extract data.
• Vertices
• Polygons
• Materials
• Animation curves

29
Exporter Initialization

• Entries of plug-in (dll / mll).
• initializePlugin()
• uninitializePlugin()
• Pseudo constructor to Maya
• MPxFileTranslatorcreator()
• Entry for exporter
• MPxFileTranslatorwriter()

30
Exporter extract vertices

• MItDag dagIter( MItDagkBreadthFirst,
  MFnkInvalid, status)
• for ( !dagIter.isDone() dagIter.next())
• MObject obj dagIter.item ()
• MFnMesh (obj, status)
• MPointArray vertexList
• fnMesh.getPoints (vertexList, MSpacekWorld )
• for (i0 ilt vertexList.length() i)
• vertexListi.cartesianize ()
• MPoint point vertexListi

31
Exporter extract polygons

• MItDag dagIter( MItDagkBreadthFirst,
  MFnkInvalid, status)
• for ( !dagIter.isDone() dagIter.next())
• MObject obj dagIter.item ()
• MFnMesh (obj, status)
• MPointArray vertexList
• fnMesh.getPoints (vertexList, MSpacekWorld )
• MItMeshPolygon piter (obj, status)
• for ( !piter.isDone() piter.next())

32
Exporter notes

• Ignore Intermediate nodes.
• Unload plug-in before you replace it.
• Use memory as effectively as possible.
• Maya Developer's Tool Kit.

33
Lecture Outline

• Introduction
• Philosophy behind Maya
• Maya programming
• Tutorial exporter
• Assignment

34
Assignment
35
Reference

• Maya API White Paper
• Book
• David Gould. Complete Maya Programming,
  Morgan-Kaufmann Publishers
• 3D User Magazine
• Web
• http//www.aliaswavefront.com/
• http//www.highend3d.com/
• http//www.learning-maya.com/

36
Appendix

• Maya Personal Learning Edition for Maya Complete
  5
• Free downloading coming Oct. 15, 2003.
• No Maya Dev-kit.
• Plug-ins does not work.

37
Thanks for your attendance