# Knowledege¶

Hopefully you find some of this helpful. It's a collection of places we've beat our heads in the wall.

Last update: 01.30.2018

## Maya Known Things¶

### 2017¶

#### Stability¶

Release 5 has been the most stable for use and improved marking menu speeds immensely. Release 4 is pretty crash happy.

Props to Charles Wardlaw for help on this. This stems from maya changing the way things work and what worked from 2011-2016 broke. However there's a pretty simple fix.

• Changing my previous c = lambda *a:self.reload() to c = lambda *a:mc.evalDeferred(self.reload,lp=True) resolved it.

#### Python update broke zoo.path and other things¶

2017 brought in a new version of Python which broke how strings were handled. Rewrote zoo.path and some other modules as Hamish isn"t developing currently.

#### UI back end changes¶

I don't have a firm answer what specifically changed but Callbacks crash maya where they didn't in 2016 and before. So in general, we try wherever possible to use lambda calls or mc.evalDeffered for ui calls to avoid it. Current understanding of what crashes: * Pushing self initialized instances into a Callback * Sometimes callbacks in general * Calling a new ui from the marking menu. Trying evalDeffered to fix this.

### 2016¶

#### Raycasting issues with OpenMaya 2.0 vs 1.0¶

Calls on OpenMaya 1 and 2 variations after some bugs were discovered with 2016 casting. Sepcifically 2.0:

• when casting at poly edge, fails
• nurbsSurface UV returns a different rawUV than 1. 1 Normalizes as expected, 2"s does not.
• nurbsSurface normal returns junk and broken

#### Hotkey system changed¶

Any previous hotkey setup tools probably broke. We"d been using zoo"s but wrote our own to address. You may find it cgm.core.classes.HotkeyFactory. The biggest add was the addition of workspace which need to be dealt with.

## Lessons learned¶

### General¶

• Sometimes maya doesn't wanna close and the task manager isn't working. In cases like this, try this:
• Windows Run - taskkill /f /im maya.exe

### Preferences¶

• Selection
• [x] Track Selection Order - Pretty important for rigging and technical purposes

### Working on other's rigs¶

Sometimes you get asked to work on other's rigs to improve them. There's a number of questions to get the answers to as you delve in.

• Check asset master control scale - sometimes rigs aren't at 1 because of whatever reason. It's tedious if you start setting stuff up and want to get your stuff in their rig and you have to deal with extra transform nodes when you parent stuff.
• Look at naming/numbering conventions and ask if they aren't clear
• You can use the select Constraints [Get Targets] call in the TD section of the toolbox for finding where the rig bits are. It's like walking through what's driving what.

### Animation¶

• If you see // Warning: Non object-space scale baked onto components. check your scale settings and put it in object mode.
• If you find objects flipping when you go back in the timeline. Select those objects and pick walk up or trace until you find aim or orient contraints. Try chaging the type from noFlip to shortest or know that the flipping will usually resolve when you go to the start of the time line because of how those work.

### Attributes¶

• MultiMessage attributes - In the end, not a fan of multi message nodes for things that we need to track specifically. When an item connected via mult message attr is duplicated. The multiMsg connections are duplicated. While this can be handy for certain things, when you need specific lists of items, it's not so hot. We developed our msgList setup for this reason.

### Joints¶

• When doing chained segments, parenting the root of the roll segment to it"s root and leaving the handle joints clean works best.
• Joints doing funky scale things? Check that the inverseScale is conected to the joint parent.
• segmentScale is a very cool attribute when you wanna do fun scale stuff. Took way to many years of working in maya before discovering it.

### Logging¶

• Log.debugs still take a hit on processing time. Watch em
• Logger is much faster that print
• pprint rules all.

### Blendshapes¶

#### Breakdown¶

• Index -- this is it's index in the blendshape node. Note - not necessarily sequential.
• Weight -- this is the value at which this shape is "on'. Usually it is 1.0. Inbetween shapes are between 0 and 1.0.
• Shape -- this is the shape that drives the blendshape channel
• Dag -- the dag node for the shape
• Alias -- the attribute corresponding to its index in the weight list. Typically it is the name of the dag node.
• Plug -- the actual raw attribute of the shape on the node. BSNODE.w[index]
• Weight Index -- follows a maya formula of index = wt * 1000 + 5000. So a 1.0 weight is a weight index of 6000.

### SkinClusters¶

• Copying skin data from many meshes to one - as in on a game project when you get your final single mesh
1. Select all the various mesh items with skinClusters
2. Add those to a new object set calling it 'sourceSkin' or something
3. Make another object set with just the new mesh in it (I've tried avoiding this step but the results aren't as good)
4. Rigging>Skin>Copy Skin Weights

#### Storage¶

• Blendshape data is stored in these arrays in real time so that if you query the data and your base mesh isn't zeroed out, the transformation happening is baked into that

• The caveat to that is that targets that have their base geo deleted are "locked" in to their respective data channels at the point they were when deleted. Their delta information is frozen.

• BlendshapeNode.inputTarget[0].inputTargetGroup[index].inputTargetItem[weightIndex]
• inputTarget -- this is most often 0.
• inputTargetGroup -- information for a particular shape index
• inputTargetItem -- information for a particular weight index
• Sub items at that index
• inputPointsTarget -- the is the differential data of the point positions being transformed by a given shape target. It is indexed to the inputComponentsTarget array
• inputComponentsTarget -- these are the compents that are being affected by a given shape
• inputGeomTarget -- this is the geo affecting a particular target shape
• Replacing blendshapes - you can 1) use a copy geo function if the point count is exact to change the shape to what you want or 2) make a function to do it yourself. There's not a great way to replace a shape except to rebuild that whole index or the node itself. We made a function to do that

• Once a blendshape node is created with targets, the individual targets are no longer needed and just take up space. Especially when you have the easy ability to extract shapes.

• Getting a base for calculating delta information. As the blendshapes are stored as delta off of the base, the best way I could find to get that delta was to turn off all the deformers on the base object, query that and then return on/connect the envelopes. I'm sure there's more elegant solutions but I was unsuccessful in finding one.

• Once you have that creating a new mesh from a an existing one is as simple as:
• Taking base data
• For components that are affected on a given index/weight: add the delta to base
• duplicating the base and xform(t=vPos, absolute = True) each of the verts will give you a duplicate shape
• Aliasing weight attributes - mc.aliasAttr("NAME", "BSNODE.w[index]")

### cmds/mc¶

• mc all the way. cmds eats toenails, Keith!
• mc.listConnections
• To get plugs properly, you need both source and destination flags set - one True, one False to get expected results. Ran into a bug where the default value in maya changed between versions. Don"t assume.

### Wing¶

Setting up wing auto completion with maya can be a bit tedious but as Josh got a new computer he had to go through it again recently and is putting it here so we don't forget.

https://wingware.com/doc/howtos/maya

Getting things setup can be a little tedious. * Project Properties

• Python executable - Point to maya mayapy.exe. Example: c:Program FilesAutodeskMaya2017binmayapy.exe
• Python path - Set to custom
• Add pi helper path. Example 
• Preferences. edit>Preferences
• Source Analysis -

### Python¶

#### Math¶

• For division, one side must be a float with versions before Python 3. 1/2 = 0 which isn't what we want. 1.0/2 = .5

#### Sys¶

• Pathing uses / on windows. - sys.path.append("d:/repos/cgmTools/mayaTools/")

#### pprint¶

pprint is a fantastic tool for logging data while working. It breaks out dict data in a readable format. Pretty sure maya started using it in 2017 or as results in the script editor got the same readabilty around that time.

• pprint.pprint(vars()) for example will print all active variables in the middle of a function without using some sort of editor to track it.

## General Computer Fluff¶

### Sphinx¶

We use sphinx, this is how we get rolling on new machines.

1. Install Python (2.76 I one we currently use for Maya reasons)
2. Open a command prompt
3. $easy_install sphinx 4. $ pip install sphinx_rtd_theme
5. Walk to doc directory
6. Make changes to rsts
7. \$ make html

### Wacom¶

• When the pen gets stuck when you click doing a right click menu. Try:
• Control Panel\Appearance and Personalization - Pen and Touch/pen Options, uncheck use the pen button as right-click equivalet

## Workflow¶

### Character Rigging¶

#### Requirements¶

New client or new project, getting to the core of what you need as quickly as possible means the faster you get to making stuff. * Ask the questions

• Is this a game rig, for render, for stills?
• What are the specific requirements for the game engine
• Joint count
• Influences per joint
• Blendshapes possible - special setup to get them working?
• Naming conventions
• Do they have one, can you use yours, do you have one?

#### Controls¶

• Zero - Controls should reset properly. If you have non-zero base values it really is helpful if those values are baked into the controls somehow. With user defined attributes this is relatively easily done by setting the default values on those attributes but you may need to do something more special with base transforms.
• Sets - It is typically beneficial to setup some sort of sets for animators to use though many want to set up their own kinds of sets. Character and object sets are usually how this is accomplished.
• DynParent groups - However you want to set them up. Having a way for your animators to change space on ik controls especially is pretty important.
• Direct controls - Typically having direct controls per joint that don't mess with joints above or below is very useful for animators.

### Layout¶

#### Starting¶

• What came before your sequence, what comes after? Sequences are just that, sequential and you need to know where what you're working on fits in that stream so you help facilitate the story or action getting where it needs to and not interupting it. Save rework time too.
• Look at the boards, ask questions, write out a list of beats as you understand them and verify them with you lead
• Technical - What are the base considerations
• Frame rate
• Specific camera or focal length the project needs (VR, etc)
• Scene units - rarely matters until that one time it does.
• Check the rigs
• Constraint groups - do you have a group to constain the whole character if your shot calls for moving in a car or elevator
• Sets - selection sets setup as you like to speed up workflow
• What do I need to hack?
• Props - sometimes a sphere or cube is all you need
• Effects - Do I need to setup lights that change or some explosions (simple spheres with ambient color and scaling work great for this) or something else?
• Set - Are there things in the set I need to sell the shot. For example, one time Josh was animating a scene with an elevator that started and stopped. Just some simple shapes in the back helped to make it clear when that was happening as the camera was following the elevator.
• Mute - Remeber when you having character moving in scene on a vehicle, often times it helps to mute whatever that vehicle is so that your regular cameras don't have to go flying through your set to keep up.

#### Tools in the Toolbox¶

• cgmSetTools - Setup a way to move all your drawings - We use selection sets that cover all referenced rigs, and any hacked stuff that will change in the shot so that you can easily retime stuff in the timeline.
• zooShots - Oldie but a goodie from Hamish. CGM>zooShots

*SnapTools - Mainly the marking menu for matching poses of specific controls when you're moving the master control around and don't want or are able to do lots of space switching on them. * ml_dragBetween - Great linear tween tool by Morgan Loomis. It's in our animation marking menus and a few other places.

## Concepts¶

Not everyone does things the same way and use terms differently. Here's some help in following what we're talking about.

### msgList¶

This was our answer to the limiatations of MultiMessage attributes where we wanted specific defined lists of items. To do this we utilized single message attribute connections in an attribute sequence. More to come

### Object Buffer¶

This is a way we store information to make things happen regardless of what you have selected or storing settings. In general we do this by optionVars As a couple of examples:

• The match buffer stores objects to use with snapping regardless of selection
• The rayCast buffer defines cast targets for raycasting.

### OptionVar¶

Option variables are maya preference items that we use mainly for ui consistancy and saving settings between sessions and between tools. For example, changing the optionVar for rayCasting options will be used by the various tools that use it.

### Raycasting¶

This is the function of using a point and vector in 3d space and shooting those rays at surfaces. We then can do all manner of things with that information.

Some possiblities are:

• Snapping to a position in space
• Getting uv data for follicles
• On interactive aiming