Pyblish Starter

A basic asset creation pipeline - batteries included.

WARNING: Not ready for use.

Table of contents

Install
Usage
Description
Terminology
Information Hierarchy
Contract

Install

Starter takes the form of a Python package with embedded plug-ins.

$ pip install pyblish-starter

Usage

Starter is initialised by calling install() with an interface for your host.

>>> from pyblish_starter import install, maya
>>> install(maya)

From here, you model, rig and animate as per the contract below.

Description

Build your own asset creation pipeline, starting with the basics.

At a glance

Categorise nodes within your workfile as being part of a single asset.
Enable an asset library to identify published data on disk.
Track when, where and from whom each asset come from.

Overview

Asset creation covers all aspects related to building the assets used in the production of film. A film is typically partitioned into sequences and shots, where each shot consists of one or more assets.

This project includes interface and implementation for 3 common types of assets a typical production pipeline.

Modeling
Rigging
Animation

The project illustrates how to (1) devise a contract - known as a family - for each kind of asset and (2) design their interface towards each other. For example, it is important for rendering and effects that the normals of each geometric surface is unlocked.

Batteries included

In addition to contracts, the project illustrates boundaries between publishing and setup. The definition of "setup" being anything that isn't strictly output, such as creating geometry or assigning attributes.

It includes a series of graphical user interfaces to aid the user in conforming to these contracts. These interfaces represent placeholders for your pipeline to fill in; you are invited to either continue from where they finish, or build your own from scratch.

Batteries

In addition to Pyblish cooperative plug-ins, a series of template workflow utilities are included.

...

Terminology

Starter reserves the following words for private and public use. Public members are exposed to the user, private ones are internal to the implementation.

Term	Public	Description	Example
`project`	`X`	Root of information	Gravity, Dr. Strange
`asset`	`X`	Unit of data	Ryan, Bicycle, Flower pot
`version`	`X`	An asset iteration	v1, v034
`representation`		A data format	Maya file, pointcache, thumbnail
`format`		A file extension	`.ma`, `.abc`, `.ico`, `.png`
`shared`	`X`	Public data	v034 of Ryan
`user`	`X`	Private data	Scenefile for v034 of Ryan

Shared/user separation

This project separates between data in progress, and data shared with others.

Data in progress is any data in which a shared data is being produced. It is highly mutable and typically private to an individual artist.

Mutable implies

Shared data on the other hand is immutable, correct and impersonal.

Immutable implies that the data may be dependent upon by other data.
Correct implies passing validation of the associated family.
Impersonal implies following strict organiasational conventions.

Ids

...

Name	Description	Example
`pyblish.starter.container`	Incoming unit of data	`...:model_GRP`, `...:rig_GRP`
`pyblish.starter.instance`	Outgoing unit of data	`Strange_model_default`

Information Hierarchy

The mental and physical model for files and folders look like this.

 ________________________________ ________________________________ 
|          |          |          |          |          |          |
| version1 | version2 | version3 | version1 | version2 | version3 |
|__________|__________|__________|__________|__________|__________|
|                                |                                |
|             asset1             |             asset2             |
|________________________________|________________________________|

Contract

Starter defines these families.

Family	Definition	Link
`starter.model`	Geometry with deformable topology	Spec
`starter.rig`	An articulated `starter.model` for animators	Spec
`starter.animation`	Pointcached `starter.rig` for tech-anim and lighting	Spec

`starter.model`

A generic representation of geometry.

Target Audience

Texturing
Rigging
Final render

Requirements

All DAG nodes must be parented to a single top-level transform
Static geometry (no deformers, generators) *
One shape per transform *
Zero transforms and pivots *
No intermediate shapes *
UVs within 0-1 with full coverage, no overlap *
Unlocked normals *
Manifold geometry *
No edges with zero length *
No faces with zero area *
No self-intersections *

Data

label (str, optional): Pretty printed name in graphical user interfaces

Sets

geometry_SEL (geometry): Meshes suitable for rigging
aux_SEL (any, optional): Auxilliary meshes for e.g. fast preview, collision geometry

`starter.rig`

The starter.rig contains the necessary implementation and interface for animators to produce

Target Audience

Animation

Requirements

All DAG nodes must be parented to a single top-level transform
Must contain an objectSet for controls and cachable geometry
Channels in controls_SEL at default values*
No input connection to animatable channel in controls_SEL *
No self-intersections on workout *

Data

label (str, optional): Pretty printed name in graphical user interfaces

Sets

cache_SEL (geometry): Meshes suitable for pointcaching from animation
controls_SEL (transforms): All animatable controls
resources_SEL (any, optional): Nodes that reference an external file

`starter.animation`

Point positions and normals represented as one Alembic file.

Target Audience

Lighting
FX
Cloth
Hair

Requirements

No infinite velocity *
No immediate acceleration *
No self-intersections *
No sub-frame keys *
Edge angles > 30 degrees on elastic surfaces *
Edge lengths within 50-150% for elastic surfaces *
Edge lengths within 90-110% for rigid surfaces *

Data

label (str, optional): Pretty printed name in graphical user interfaces

Sets

None

Legend

	Title	Description
	Target Audience	Who is the end result of this family intended for?
	Requirements	What is expected of this asset before it passes the tests?
	Data	End-user configurable options
	Sets	Collection of specific items for publishing or use further down the pipeline.
	`*`	Todo

Example

The following is an example of the minimal effort required to produce film with Starter and Autodesk Maya.

Table of contents

Setup
Model
Rigging
Animation

Setup

Before any work can be done, you must initialise Starter.

# Prerequisite
import pyblish_maya
pyblish_maya.setup()

# Starter
import pyblish_starter
pyblish_starter.setup()

Modeling

Create a new model from scratch and publish it.

from maya import cmds

cmds.file(new=True, force=True)

cmds.polyCube(name="Paul")
cmds.group(name="model")
instance = cmds.sets(name="Paul_model")

data = {
    "id": "pyblish.starter.instance",
    "family": "starter.model"
}

for key, value in data.items():
    cmds.addAttr(instance, longName=key, dataType="string")
    cmds.setAttr(instance + "." + key, value, type="string")

from pyblish import util
util.publish()

Rigging

Build upon the model from the previous example to produce a rig.

import os
from maya import cmds
from pyblish_starter.maya import (
    hierarchy_from_string,
    outmesh,
    load
)

cmds.file(new=True, force=True)

# Load external asset
reference = load("Paul_model", namespace="Paul_")
nodes = cmds.referenceQuery(reference, nodes=True)
model_assembly = cmds.listRelatives(nodes[0], children=True)[0]
model_geometry = outmesh(cmds.listRelatives(
    model_assembly, shapes=True)[0], name="Model")

assembly = hierarchy_from_string("""\
rig
    implementation
        input
        geometry
        skeleton
    interface
        controls
        preview
""")

# Rig
control = cmds.circle(name="Control")[0]
skeleton = cmds.joint(name="Skeleton")
preview = outmesh(model, name="Preview")
cmds.skinCluster(model, skeleton)
cmds.parentConstraint(control, skeleton)

# Sets
sets = list()
sets.append(cmds.sets(control, name="all_controls"))
sets.append(cmds.sets(model, name="all_cachable"))
sets.append(cmds.sets(reference, name="all_resources"))

# Organise
cmds.parent(input_, "input")
cmds.parent(control, "controls")
cmds.parent(skeleton, "skeleton")
cmds.parent(model, "geometry")
cmds.parent(preview, "interface|preview")
cmds.setAttr(control + ".overrideEnabled", True)
cmds.setAttr(control + ".overrideColor", 18)
cmds.hide("implementation")
cmds.select(deselect=True)

# Create instance
instance = cmds.sets([assembly] + sets, name="Paul_rig")

data = {
    "id": "pyblish.starter.instance",
    "family": "starter.rig"
}

for key, value in data.items():
    cmds.addAttr(instance, longName=key, dataType="string")
    cmds.setAttr(instance + "." + key, value, type="string")

from pyblish import util
util.publish()

Animation

Build upon the previous example by referencing and producing an animation from the rig.

from maya import cmds
from pyblish_starter.maya import (
    load,
    create
)

cmds.file(new=True, force=True)
cmds.playbackOptions(animationStartTime=1001, maxTime=1050)

# Load external asset
reference = load("Paul_rig", namespace="Paul01_")
nodes = cmds.referenceQuery(reference, nodes=True)

# Animate
all_controls = next(ctrl for ctrl in nodes if "all_controls" in ctrl)
control = cmds.sets(all_controls, query=True)[0]

keys = [
    (1001, 0),
    (1025, 10),
    (1050, 0)
]

for time, value in keys:
    cmds.setKeyframe(control,
                     attribute="translateY",
                     value=value,
                     time=time,
                     inTangentType="flat",
                     outTangentType="flat")

# Create instance
all_cachable = next(ctrl for ctrl in nodes if "all_cachable" in ctrl)
cmds.select(cmds.sets(all_cachable, query=True))

instance = cmds.sets(name="Paul_animation")

data = {
    "id": "pyblish.starter.instance",
    "family": "starter.animation"
}

for key, value in data.items():
    cmds.addAttr(instance, longName=key, dataType="string")
    cmds.setAttr(instance + "." + key, value, type="string")

from pyblish import util
util.publish()

Requirements specification

The following is a details description of each requirement along with motivation and technical reasoning for their existence.

Workout

A workout is an animation clip associated with one or more character rigs. It contains both subtle and extreme poses along with corresponding transitions between them to thoroughly exercise the capabilities of a rig.

The workout is useful to both the character setup artist, the simulation artist and automated testing to visualise overall performance and behavior and to discover problems in unforeseen corner cases.

Self-intersections

Three dimensional geometric surfaces inherently share no concept of volume or mass, but both realism and subsequent physical simulations, such as clothing or hair, depend on it.

Implementation tip: A toon shader provides an option to produce a nurbs curve or mesh from self-intersecting geometry. A plug-in could take advantage of this to test the existence of such a mesh either at standstill or in motion.

Extreme Acceleration

In reality, nothing is immediate. Even light takes time to travel from one point to another. For realism and post-processing of character animation, such as clothing and hair, care must be taken not to exceed realistic boundaries that may complicate the physical simulation of these materials.

Extreme Surface Tangency

In photo-realistic character animation, when the angle between two edges exceeds 120 degrees, an infinitely sharp angle appears that complicates life for artists relying on this surface for collisions.

To work around situations where the overall shape must exceed 120 degrees - such as in the elbow or back of a knee - use two or more edges. The sum of each edges contribute to well beyond 360 degrees and may be as short as is necessary.

Extreme Surface Stretch or Compression

Surface stretch and compression on elastic surfaces may negatively affect textures and overall realism.

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README.md

README.md

Pyblish Starter

Install

Usage

Description

Batteries

Terminology

Shared/user separation

Ids

Information Hierarchy

Contract

`starter.model`

`starter.rig`

`starter.animation`

Example

Setup

Modeling

Rigging

Animation

Requirements specification

Workout

Self-intersections

Extreme Acceleration

Extreme Surface Tangency

Extreme Surface Stretch or Compression

Files

README.md

Latest commit

History

README.md

File metadata and controls

Pyblish Starter

Install

Usage

Description

Batteries

Terminology

Shared/user separation

Ids

Information Hierarchy

Contract

starter.model

starter.rig

starter.animation

Example

Setup

Modeling

Rigging

Animation

Requirements specification

Workout

Self-intersections

Extreme Acceleration

Extreme Surface Tangency

Extreme Surface Stretch or Compression

`starter.model`

`starter.rig`

`starter.animation`