Pixar's Renderman: Analytic Lights and PxrMeshLight

 When I was learning Pixar's Renderman for my student film Delivery, during my research I learned about analytic lights and how they effect render times.  I am not a lighting artist but its still very good to know how Renderman calculates lights especially if you have a special case that is uses lighting differently. 

The primary mode of lights in renderman are called analytic lights because they are economical to render time.  They are highly mathematical modeled lights, highly efficient, and they use aerial lights.  Thus they are calculated cleaner and give us a faster result. 

    Analytic lights include:

• PxrRectLight
• PxrDiskLight
• PxrDistentLight
• PxrSphereLight
• PxrDomeLight
• PxrPortalLight
• PxrEnvDayLight

Autodesk Maya 2022 Renderman's Analytic Lights

An example of a light that isn't analytic is the PxrMeshLight.  If you use this light, you won't get the same speed and cleanliness in the scene.  What the PxrMeshLight does is it makes objects emissive.  It's better than a glow material but it is not economical like analytic lights.  This does not mean to not use this light, sometimes you do need to use this light for objects that are illuminating.  

How to use the PxrMeshLight: 

1. Select an object in your scene.
2. Select it's icon on the Renderman shelf. 
   
   

    3.  To edit it's settings, simply click on it's node under the object you put it on in the outliner. In the channel box you can edit each of the settings. 

Gif of Autodesk Maya 2022 Applying the Renderman's PxrMeshLight

Autodesk Maya 2022 Example of Renderman's PxrMeshLight

The Difference Between FK and IK Controllers

 If you are an animator or someone who is very into rigging, then you have probably heard about FK and IK controllers.  This is just a short write up about the differences between FK and IK controllers with Lucy from the Delivery project as an example.  

Forward Kinematics or FK controllers are often times used when creating expressive animation.  These controllers are very good at capturing realistic movement.  The logic behind these controllers is that the top controllers holds all the controllers underneath it.  It's a parent-child relationship!  Because of the nature of the parent-child relationship they are animated through rotation.  While these are all of the positives about this controller set up, FK is not very good when you need a character or object to rest their weight on something.  You will need to counter animate.  

Autodesk Maya 2022 Gif of Lucy FK Controllers

Inverse Kinematics or IK controllers are used when you need something to independently "stick".  These controllers are interesting because the top controller is independent of the bottom controller.  When you move a controller anything between the two controllers is being solved by the computer.  It is sticky so for example if you put a hand on a table and you try to move the table the hand will go with it if parented.  Because of the nature of how it works, you are animating through translations.  This type of controller does require a more complicated set up and it is more difficult to get realistic animation when you aren't resting weight. 

Autodesk Maya 2022 GIf of Lucy IK Controllers

Rigs can be built with both FK and IK controllers.  Somtimes they may be built with only FK or only IK.  In some cases if you character or object has a specific movement you may even have other set ups such as FK space.   

Idle to Walk Mocap Animation Part 2: Adding the Character

Motion Builder 2022 Trimmed and Plotted Azura Walk Animation

For this week I chose to work on adding the mocap data to a character.  For this animation, I worked with a character named Azura who you may recognize from the Fire Emblem series.  This rig is of her special costume and I got her rig from my grad school mocap rig library.  I though she had a very cool design and she also had some very interesting hair and clothing.  I find hair and clothing very interesting and something I want to learn more about so working with her would give me some more insight on how hair and clothing work when it's time to work with both of those areas.  

To start off I open Azura in motion builder.  I then also add my folder path to my cleaned and characterized mocap data in the asset browser so that it is easier to work with.  After adding my folder path, I drag one of the mocap animations onto the scene and FBX merge.  

Motion Builder 2022 Azura and Mocap Data Rig

From here I select my character in the navigator outline and switch her Input Type to Character under the Character Settings.  I also plot the character so I can delete the mocap data from the scene.   After I plot my character I opened my schematic and deleted the mocap data.  Azura has many nodes in the schematic view!

Motion Builder 2022 Cleaned Plotted Character Schematic

After I plotted my character, I created a new folder for my plotted scenes and saved my scene.  I did the same process for my other animation before I moved into trimming the animation.  

Motion Builder 2022 Short Gif on Azura Idle Animation

Motion Builder 2022 Short Gif on Azura Walking

Once I got both of my animations plotted I began to look at where I could begin trimming.  Because these animations weren't given direction when shooting the mocap, I will have to copy some keyframes for when I merge the two animations together.  What I mean by they weren't given direction I mean that the actor wasn't told to lower their arms first from T-pose before beginning to walk.  

Once I find the frames that I want to cut using the cut filter, I set my set start to 0 and my set stop to the frame I want my animation to begin. I then used the same technique to cut off the animation at the end.  For the walk I kept it simple and short.  For the idle I'm going to be showing that one's trim in the next post!

Motion Builder 2022 Azura First Walk Frame After Getting Trimmed

Idle to Walk Mocap Animation Part 1: Cleaning and Characterizing.

Motion Builder 2022 Short Gif Cleaned and Characterized Walk Animation

Motion Builder 2022 Short Gif of Cleaned and Characterized Idle Animation

I decided that I wanted to gain some more knowledge about mocap animation and learn about the animation process in motion builder.  To start my journey on learning more about this area, I started simple with just a basic walk and idle animation.  I'm starting these animation off separately before I combine them into one.  While I was in grad school,  I went to some of the lectures about mocap animation.  I never got to finish any of the animations but I did learn a lot from my professor.  

To start off, I found my mocap data from the animation I started in grad school.  I'm starting from the very beginning where I have to clean and characterize the data.  I see many red dots in the scene which is data I need to clean.

Motion Builder 2022 Original Walk Animation 

To begin cleaning the scene, I first start with opening the schematic.  I deleted the system, unlabeled markers, markers for props that were not used, and the markers that were on the actor.  

Motion Builder 2022 Unclean Schematic View

Motion Builder 2022 Clean Schematic View 

Motion Builder 2022 Clean Perspective View

To take the cleaning process a bit further, I characterized the scene.  Characterizing allows me to label the joints to transfer the data to a mocap rig.  I first set the starting frame at 0.  I also zero out all of the rotations.  I then selected just the hip joint and rotated the X 90 degrees. Next selected everything and keyed it on frame 0.  Finally, added a template character and renamed it Mocap so I know what the mocap data is.  At this point I save my cleaned file in a new folder. 

Motion Builder 2022 Cleaned and Characterized File

I then run through this very same process for my idle animation.

Motion Builder 2022 Original Idle Animation Short Gif

Jaw Pivot - Good Way To Figure Out Where This Joint Should Be and The Effects You Get

 It's been a while since I have worked on this project.  Sometimes life gets a bit crazy and this is a project I am picking back up. When I was creating my joints for my jaw pivot, I learned something I didn't really think about too much.  I think about anatomy a lot when I work on a character by looking at several real life skeletons and looking at animation.  With the jaw pivot, the whole idea of where it can be placed to get different effects really got me thinking.  

When I placed my joints, I placed it based on realism.   I placed my jaw hinge joint close to the ear and close to where the neck would be connecting to the skull.  It's very similar to a drawing my instructor did in class.

Autodesk Maya 2022 Joint Placement

Drawing from Facial Rigging Class

A really interesting point about the jaw hinge that I learned is that they don't always just rotate.  They will also translate a little bit when it gets to a certain point.  For more realistic rigs, you can leave rotation and translation turned on so that it is easier for the animators.  Animators can adapt it a little bit.  I also learned that with realistic facial rigs you can create the jaw open with shapes and the motion would be build in.  

Cartoon rigs are different from realistic rigs because the design of the character will become a consideration on how you want them to move.  They may have a very long nose like Goofy or very long fingers.  This same idea applies to the jaw.  Where you place your jaw hinge will give you a different effect for how the jaw moves.  An example I looked at was if you wanted your jaw to move almost vertically, your pivot would have to very far away so that when you rotate it would move more vertical.  

Example of Jaw Hinge for Vertical Movement

Another example that was looked at is if the character was designed to have a very sharp rotation.  The pivot point would actually move further way from the ear and closer to the jaw.

Example of Jaw Hinge for Sharp Rotation

A cool trick that I tried for visualizing how the pivot is going to act is to bring a cylinder into the scene and then rotate it 90 so that it's on it's side.  You would be looking at the vertices that create the center of the cylinder.  Then bringing it up into the head geometry and turning on xray.  You can use the center, scale and place it where you think you want to put your jaw hinge joint.  Tip:  The more subdivisions you have the smoother it looks.  Then rotate the cylinder, this will give you an idea as to what kind of effect you will get. 

Gif Example of Sharp Rotation

While I haven't had the experience of creating a rig with a vertical movement or a sharp rotation, I found this to be very interesting and hope I can create a rig with these effects in the future!

Resetting Transformations, Freezing Transformations, and Matching Transformations in Autodesk Maya

 When working in maya you may use several transformation tools to help with your workflow.  The three translation tools I want to talk about are the resetting transformations, freezing transformations and matching transformations.  These three tools are very powerful and help you work in maya in many different ways.  I used these tools in my school days a lot and still do on the daily.  

Resetting Transformations is a tool that put your manipulator tool back at the origin in maya.  So back on the center of the grid.  

How to reset transformations:

1. Select an object you want to reset the transformations on
2. Go up to Modify 
3. Select Reset Transformations

Autodesk Maya 2022 Reset Transformations Tool

Freezing Transformations tells maya that the point where the object is, is the origin.  So if you move the object you can zero out the transformation, scale, and rotation and it will go back to where you froze.

How to freeze transformations:

1. Select an object you want to freeze transformations on
2. Go up to Modify
3. Select Freeze Transforms. 

Autodesk Maya 2022 Freeze Transformations Tool

Matching Transforms is a tool that I learned recently from a friend of mine at work.  Matching transforms copies the translations from one object to another.

How to match transformations:

1. Select the object you want to transform and then the target you want your object to match.
2. Go up to Modify and scroll down to Match Transforms.
3. On the side pop-up you can select a variety of ways you can have your object copy the transforms
1. Match all Transforms
2. Match Translations
3. Match Rotation
4. Match Scale
5. Match Pivot

Autodesk Maya 2022 Match Transformation Tool.

Each of these tools are incredibly powerful and helpful when working in maya.  If you are a tech artist, you may recognize that each of these tools utilizes different matrix. 

Maya 2022: Unable to Playblast using Quicktime and H.264

If you are someone who has used maya for a few years you may have noticed some changes to maya 2022 and maya 2020.  One of the changes I have come across when playblasting my dance animation to Kiss and Make Up, is that QuickTime is no longer an option in the playblasting options.  If you are newer, you would find the quick time option under format in the playblast settings and H.264 disappears from the encoding setting.  These settings are easy to get back but it does require installing QuickTime.  Quick note, I have found this issue on both PC and Mac computers.

To get the QuickTime option back is very simple.

For a PC:

1. Start off with maya closed.  It needs to be closed because we need to install quicktime.  
2. You need to visit the Download Quick Time page.  This download is on an apple support page and is only for PC.
3. Push the big download button on this page and install quick time.  
4. Open maya and check both your playblast settings format and your render settings

For a Mac:

• You need to follow the same steps above but you need to visit Quicktime Downloads by Apple support.

Maya 2022 Playblast Settings with QuickTime and H.264