Ziva Anatomy Transfer is a set of tools to transfer creature geometry and Ziva rigs from a source creature onto a new creature.

Anatomy transfer makes it possible to design a Ziva creature once, then automatically transfer all of the geometry and rigging work onto another creature. The intent is to transfer creatures that are similar in shape. For example, Ziva Anatomy Transfer can transfer subjects of the same species, such as a horse onto another horse (of different shape/proportions), a slim male to a fat male, or a male to a female. They are also suitable for warping within a related family of species, such as, for example, warp a horse onto a zebra, or a cat onto a lion.

Here, we discuss the various options for warping geometry from the source creature to the target creature. Ziva Anatomy Transfer supports 3 warping methods: harmonic warp, bone warp and radial basis function (RBF) warp.

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‍Bone Warp

This is a specialized tool for warping Maya meshes that represent bones. In contrast to the harmonic warp, the bone warp keeps the bones straight and avoids distorting the boneheads’ geometry. The user provides the source and target cage meshes (such as the skin of the source and target creatures), the bone geometry to warp, and a landmark map. Landmarks are important anatomical features on the bone whose relative positions need to be preserved by the warp. The landmark map can be painted on the bone geometry interactively. A landmark is then placed automatically at the center of each “blob” (connected region with non-zero map values) of the painted landmark map. For each blob, the landmark position is computed as the average position of vertices in the blob, weighted with the painted vertex weights. Landmarks can be visualized by selecting the zBoneWarp node.

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Harmonic Warp (meshes, NURBS, joints, or locators)

This is the general-purpose method to warp the geometry (such as creature anatomy) from the source creature onto the target creature. The user provides the skin meshes of the source and target creatures, as well as the source creature’s geometry (such as internal anatomy) to warp. This feature can warp Maya meshes, representing, for example, tissues (muscles) or cloth objects (fascia). It can also warp Maya joint hierarchies, locators (including their orientation), and Maya curves and NURBS surfaces.

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Cut, Copy, Paste

Ziva Anatomy Transfer supports multiple operations to manage, copy and modify Ziva rigs, all of the options can be found under the Ziva Transfer menu. Once you have the completed geometry of the new creature, the last step is to copy the Ziva rig from the source creature. The Ziva menu include tools for loading and saving a Ziva rig, which will automatically transfer properties such as attachments, fibers, materials, simulation mesh, etc. For example, suppose you already rigged a part of the creature. Suppose you want to rig additional geometry that has the same number of mesh vertices and triangle connectivity (but not same vertex positions) as the already rigged objects. Then you can select those already rigged objects, copy them, and paste their Ziva rigs onto this previously un-rigged additional geometry. Note that for copying an entire Ziva rig of a creature onto a “clean” un-rigged creature, either into the same solver or into a separate solver, you can also use the zRigTransfer script. For more script information, click here.

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RBF Warp

This is a general-purpose warp that is primarily useful to warp geometry that is located externally of the creature’s skin, such as hair or eyebrows. This warp can only warp Maya meshes. In order to execute the warp, select the source creature skin, target creature skin, and one or more meshes to warp.