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TOTAL DURATION: 2h 45m 21s

Learn how to rig, animate and add fur to a two legged character named Fur Dude. Starting with existing geometry, draw the skeleton, capture the geometry then build rig controls for an animation rig. Next keyframe a walk cycle and add fur to the surface of the creature.

This lesson uses KineFX, Houdini’s new SOP-based procedural rigging tools. While these tools are used primarily for retargeting workflows they also include tools for rigging characters and creatures. These tools are still evolving and this lesson offers a taste of what will be currently possible. In future releases, you will see the KineFX and animation workflows expanded and refined.

Houdini Foundations for Houdini 19.5 is now available as Downloadable PDF and a Print-on-Demand book through the Lulu Ebook company. This 224 page book contains 9 chapters designed to help artists take their first steps into Houdini.

Research for this lesson by Marcia Utama. She developed a version of Fur Dude available in the Content Library which was rigged at the Object level. Also thanks to Keith Acheson for creating the original Fur Dude animation.

A quick overview of all the different parts of this lesson. Take a look at the steps you will be completing as you work through these videos.
Open the scene file and review the Fur dude geometry then place joints using the Skeleton tool. This tool will let you create, name and adjust joints to line up with the character you want to animate.
Rigging a character involves capturing geometry to the skeleton joints in such a way that rotating the joints deforms and bends the geometry. Houdini uses a biharmonic capture method that gives great results with your first capture so that you can start testing out your rig right away. Later you will paint capture weights to refine the results to work with your character.
It would be nice to have more bones in the mouth area. The procedural networks in Houdini let you go back and add the joints and all the other nodes including the biharmonic capture will update to reflect the changes. This gives you flexibility when first setting up your creature’s rig.
When you animate the character, the orientation of the joints plays a significant role in how you manipulate the rig. At this point, you will orient some of the joints by hand and then use an Orient Joints node to point all the other joints down the -z axis. Sometimes when you evaluate your rig at a later stage, you may need to come back and tweak the orientations.
Right now you are using the skeleton joints to capture geometry and assign capture weights to each point on your character. To manage this with more control, you can attach curves to the joints that will extend the influence of that joint. This provides a method for achieving your goals as quickly as possible.
The biharmonic capture added weights to the character’s geometry that are associated with the different skeleton bones. You can now use a new node to adjust the capture weights using a brush workflow. For this creature, the goal will be to get the top of the mouth to not be influenced by the lower mouth joint and to tweak how the feet area is weighted.
Earlier you split out the eyes, teeth and claw geometry. Now you are going to pack this geometry then assign each part to a joint using the capture packed geometry node. This is the equivalent of parenting each object to the skeleton since parenting isn’t an option at the geometry level when using KineFX.
The captured geometry and the skeleton can now be wrapped up into a digital asset that can be used as the foundation for the animation rig. To start, you will export the geometry with its capture weights and the skeleton then embed these into the digital asset file. This will help make the capture rig more efficient when animating the character.
You are now going to create a second digital asset that has the capture rig nested inside it. This new asset will be the one that can be animated to create the final motion of the character. This new asset will contain all of the rigging tools such as inverse kinematics and aim constraints that assist with animation. In order to test these controls as you add them, you will set up a test version of the rig that is locked and visible in a second Scene view pane.
To provide more flexibility with the control rig, you can add joints such as a root joint for the whole skeleton, heel joints for a reverse foot setup or a look-at point for you to target with your eyeball. These joints will have the same names as the ones in the original rest skeleton and that will ensure that they are used to drive the motion on the character.
To add kinematics, you need to break the current hierarchy where the feet are under the COG. You can break off a few joints and reparent them to build the hierarchy you need. This reparenting happens off to the side then you will blend the results back into the original skeleton hierarchy which is important to make sure the bone deform functions properly.
To animate a character, Inverse Kinematics allow you to set up the legs so that moving either the feet or the hips causes the knee to bend appropriately. You are again going to pull out some joints from the main skeleton and set them up using KineFX. You will again blend the results back into the original hierarchy.
To control the feet, you will create a classic reverse foot setup where the heel becomes the root then the toe, ball and ankle are parented to that. This can be easily accomplished in KineFX and the results blended back into the original skeleton. In this case you will completely rebuild the right foot but since the joint names align everything works properly.
To make all of the leg and spine controls available to the animator, the parameters need to be promoted to the top level of the asset. This is an important step that is always needed to give the animator the control they need. This also means that you can keep certain parameters hidden that you don’t want animators to work with.
The next step is to set up the eyelids with control geometry to make it easier to select these overlapping joints. You will also set up the eye target joint as a look at for the eyeball using a different section of Houdini called VOPS. When these parts are rigged, you will again promote the appropriate parameters to the character’s asset.
It is time to keyframe a walk cycle for the fur dude character. This will involve new tools such as the Channel List to pin down channels for blocking out the motion. The results will be a quick and dirty walk cycle designed to see fur dude in action. The goal is to map out a basic keyframe workflow to learn a bit about how to animate KineFX rigs.
Fur dude gets his name for a reason and you are going to work with a variety of grooming tools to add and shape the hair. Using a desktop designed for grooming, you will add frizz, clumping and hair dynamics which will simulate as fur dude walks. The end result will be ready to be exported for rendering.
To render the shot, you will reference the USD files into the Solaris Stage then add a backdrop. Solaris is a Houdini context that uses LOP nodes to set up a USD Scene Graph. Next, you will import the fur then add and position a camera and a light. The Karma renderer will then be invoked to create a preview render of the shot then render out the animated sequence.

CREATED BY

rmagee
ROBERT MAGEE

Robert Magee is a Senior Product Marketing Manager at SideFX who has been working with Houdini for 20 years. He has created lots of learning material and demos designed to help artists understand how going procedural with Houdini can benefit their work.

More from Robert Magee

COMMENTS

  • 1h8g9s5 1 year, 9 months ago  | 

    wow KineFX videos updated! I'm diving right into it

    • zero_expectations 1 year, 9 months ago  | 

      Hurray! It's here!
      Thanks Robert!

      • AlfredoSMC 1 year, 9 months ago  | 

        Thanks Robert,
        it is completely excellent,
        I had already followed a large part of this tutorial with skeleton, but now you incorporated the hair, and I already have some experience in hair, but (guide simulate is amazing) it has vellum incorporated.
        thanks again!

        • AlfredoSMC 1 year, 9 months ago  | 

          but to be honest, I prefer the guide process, it is very very complete.

          • jimr@sidefx.com 1 year, 9 months ago  | 

            Is there supposed to be audio on 13?

            • rmagee 1 year, 9 months ago  | 

              It was missing from the video - it has been re-uploaded with sound.

            • BunglebeetTV 1 year, 8 months ago  | 

              How do you select Spacebar to the right view? Thanks in advance.

              • Michael_Mietz 1 year, 4 months ago  | 

                Ctrl+4 or Cmd+4 to go into Four Views
                Then hover over the view you want to make full screen and hit Space+B.
                Space+B again to go back to Four Views

              • li la 1 year, 8 months ago  | 

                Can I get the completed houdini file?
                I'm facing a problem where I can move but can't rotate, and I want to see the difference from the correct node.

                • reductioabsurdum10 1 year, 4 months ago  | 

                  Thank you 100 times for keeping this video up to date!!!

                  • reductioabsurdum10 1 year, 4 months ago  | 

                    Can you make a tutorial on how to model fur dude?

                    • jamalsb176 1 year, 4 months ago  | 

                      Weldone Robert !

                      • 0ldsl0 1 year, 1 month ago  | 

                        When attaching the capture geometry, i get a warning saying that it needs a valid rest_transform attribute and when I check the skeleton it needs does not have one. It only has a local transform attribute and I'm fairly certain I've been following along exactly...

                        • arekrataj 1 year, 1 month ago  | 

                          You need to uncheck "Rest Pose Attribute" option under "Add Shapes" tab of "Attach Capture Geo" node.

                        • Ela_Eichu 11 months ago  | 

                          There is no fur_dude folder in the opdef:/sop/ directory. I'm using Houdini apprentice 20, what did I do wrong?

                          • Ela_Eichu 11 months ago  | 

                            I found it- Houdini 20 adds a few fields when naming a HDA, so the folder had my personal name as part of the Author field.

                          • alesia_karchevskaia 10 months, 1 week ago  | 

                            Great series, learned a lot so far!
                            However, when I promote the parameters to the top of the HDA andsave it, the control geometry doesn't show up on the test rig. I can use the parameters but do not see the controls themselves. What have I missed?

                            • rmagee 10 months, 1 week ago  | 

                              I would have to see your rig - send me your asset (rmagee@sidefx.com) and I will take a look.

                            • mtea9152 9 months, 3 weeks ago  | 

                              Adding the "IK Chains" node will twist the knees.
                              The character's knees twist inward.
                              If you move the knee joint outward with "Knee_offset", the knee will face forward.
                              When the character bends down, his legs become crab-like.

                              • ROGA_high 7 months ago  | 

                                Hi-Hola, it is indeed a great series. I also have that issue. I cant see the CTRLs of the rig. I also ccan use the parameters but cant see the CTRLs. Did you two found a solution for this issue?

                                • Damon_lavenski 4 months, 1 week ago  | 

                                  Assistance Needed with Step 7 in Houdini 20.5

                                  Hi all

                                  I’m having trouble with step 7. I’m using Houdini 20.5 and have noticed that after adding the extra files as instructed in the video and the PDF, the folder for the fur dude hasn’t been created in the “opdef/sop” directory. Since the UI is new and different, is there something I need to name differently to make it work?

                                  Additionally, in the “Edit Output Properties” UI, the “Save to Library” field is pointing to the OneDrive folder. I’m not sure why it’s doing that. Is this part of the new features?

                                  Lastly, I’ve noticed that the file type extension is not showing up when I go into one of the other folders. I think the extension should end with “.sc”. Is there any way I can fix this as well?

                                  I would appreciate a step-by-step explanation on how to resolve these issues. This is a wonderful tutorial, but this is the first time I’ve really gotten stuck.

                                  Thanks in advance for all the help! :)

                                  Best regards,

                                  • Damon_lavenski 4 months, 1 week ago  | 

                                    It's step 7 on the PDF. But it's video 9 the headline for the section is"Create Capture Rig Digital Asset"

                                    • Damon_lavenski 4 months, 1 week ago  | 

                                      I finally figured it out. Here’s what to do if you’re using the new UI for creating assets. In the video and the PDF, the instructions clearly dictate how to name the asset. The difference in the UI is the internal name field, which is segmented into three parts: author in blue, base name in yellow, and version in pink.

                                      There’s also a drop-down list for more options to control adding the author namespace. You have two options at this point: name the author in the blue field, or in the “Add author to namespace” option. You can choose to uncheck the box if you prefer.

                                      Now, regarding the path: as I mentioned above, the path that was created for me by default was not the one I needed. There is also a drop-down list for the “Save to” field, where you can choose the location you wish to save your asset (e.g., the $HIP directory). You might get a couple of errors telling you that the path may not be a Houdini pipeline path, but if you want to follow this tutorial, you can change it to match it.

                                      • rmagee 4 months ago  | 

                                        If you are working with Houdini 20 or 20.5, there is a new rigging workflow - I am working on updating the lesson to include that - no timeline for release but I would suggest waiting and exploring other Houdini 20.5 lessons in the meantime. Also check out the Content Library examples. In the new workflow digital assets will not be required to set up and share the rig.

                                        • AimSouthSideFX 4 months ago  | 

                                          Love you, man... We're waiting for your new rigging tutorials!

                                        • toonafish 3 months, 4 weeks ago  | 

                                          Thanks for the nice tuts.

                                          Been trying to wrap my head around KineFX / Apex rigging and so far nothing but crashes, bugs, Python errors and frustration.

                                          Try using the Joint Capture Paint Spreadsheet and adjust the weights of some selected points, it will crash Houdini to the desktop every time in 20.0 + 20.5. And when it doesn't the auto normalizing of the weights is completely broken. Looks like its limited to only manually painting the weights, all other roads seem to be a dead end.

                                          Does anyone know how to refresh the Joint Capture Biharmonic manually ? Because when I add or remove some geo from the Rest Geometry, the rig often breaks.

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