For the sake of completeness we are going to look at taking a character that is only a mesh, add a skeleton to it, and then animate it before bringing it back into Houdini. You can see the character inside Houdini (fig. 1). The first step is to go to File -> Export -> Filmbox FBX. FBX is a common file format used for 3d file exchange and is recognized by Mixamo.
Once you’ve saved your file, navigate to Mixamo.com and click on the characters tab and click on the Upload character section. (fig. 2)
Click the upload button and locate your character file on your hard drive. Once it has been selected, you will be taken to a screen where you can orient the character to face forward.
Once you click on the rig button, you will be able to place markers, which will allow you to auto-rig. Once the markers are placed you can click preview and your character will auto-rig. (fig.3)
You now have a character in your Mixamo account. Completing the process will take you to the Auto-Rig Success page. Once there you can download your character, or in our case, click on the animate your character button. You’ll be taken to a page where you can search for animations.
For this example, we will pick a free motion, the samba dancing. Click customize under the thumbnail and you should see your character performing the animation. (fig. 4)
If you want to create a cloth simulation with your character then be sure to add a T-pose at the beginning of the animation. Click save to save this particular motion and character in your collection.
Now that you have a character with animation applied to it, you can download it for Houdini. Click on the motions tab and you should see your animation with the character. Click on the clip you want and then select fbx from the Download Format list at the top. Click the orange download button and your file will download. (fig. 5)
Return to Houdini and create a blank scene. Select File -> Import -> filmbox FBX. In the top field, enter the path of the file that you downloaded from Mixamo and select either import or merge. Merge will add the file to your current scene and import will create a new scene that doesn’t matter at this point. (fig. 6)
When you import the fbx into Houdini, the Mixamo motion will be brought into on an animation layer that is called “take” in Houdini. If you click on the Take list window, you will see the hierarchy of takes. Drag the Mixamo take onto the Main take and select “merge with overrides” from the menu that pops up. Then you can delete the two takes under main. This will make the scene easier to work with.
All that’s left is to hit play and see your character animated in Houdini.