How Properties Are Propagated

Objects can inherit properties from many different sources. This inheritance is called propagation.

For some properties, such as Display and Geometry Approximation, an object can have only one at a time. If it inherits the same property from more than one source, the source with the highest “strength” is used.

In increasing order of strength, the possible sources of property propagation are:

Scene Default: This is the weakest source. If an object does not inherit a property from anywhere else, it uses the scene’s default values. For example, if an object has never had a material applied to it, it uses the scene default material.

Branch: If a parent has a property applied when it is branch-selected, its children all inherit the property.

Local: If a child inherits a branch property from its parent, but has the same property applied directly to it, it uses its local values.

Cluster: Materials, textures, and other properties applied to a cluster take precedence over those applied to the object.

Group: If an object is a member of a group, then any properties applied to the group take precedence over local and branch properties. Similarly, if a cluster is a member of a group, any properties applied to the group take precedence over those applied directly to the cluster.

Scene Layer: Any properties applied to the scene layer that contains an object take precedence over group, local, and branch properties.

Partition: Properties applied to a partition of a render pass have the highest priority of all when that render pass is current.

For other types of properties, an object can have many at the same time. For example, an object can have several local annotations as well as several annotations inherited from different ancestors, groups, and so on.

Overrides provide a way to impose properties and parameter values outside of ordinary propagation. For more information, see Overriding Properties.

 

 

Simple Propagation
In this sphere hierarchy, each sphere is parented to the one above it. Because the larger sphere was branch-selected when the texture was applied, every sphere beneath it inherits the checkerboard texture.

Branch Propagation
One sphere was branch-selected and given a cloud texture. The remaining sphere retains the checkerboard texture because it is on another branch.

 

 

Local Material/Texture Application
One sphere was single-selected and given a blue surface. This applies a local material/texture that is in turn applied to the selected object only — and none of its children; the sphere’s children still inherit the checkerboard texture, despite assigning a local texture to their parent.

Reverting to the Scene’s Default Material
The larger sphere was single-selected and has had its material deleted. Since other spheres can no longer inherit their texture from the parent (because its been deleted), they revert back to the scene’s default gray (or another color you’ve defined).

Viewing Propagation in the Explorer

The explorer is useful not only for viewing your scene’s elements and their properties, but also for viewing how they are propagated through various hierarchies.

 

A

Properties that are applied in branch-mode, and therefore propagated, are marked with B.

B

Shared properties such as materials are shown in italics. The property’s source (where it’s propagated from) is shown in parentheses.

If no source is shown, then it is inherited from the scene root.

You can also set the following options in the explorer’s View menu:

Local Properties displays only those properties that have been applied directly to an object.

Applied Properties shows all properties that are active on a object, no matter how they are propagated.

Viewing Propagation in the Schematic View

The schematic view offers a hierarchal representation of how an object’s properties relate to one another.

 

A

Sphere2 has a branch material applied to it, which is propagated to Sphere6 and 7.

B

Sphere6 has its own local material applied, which takes precedence over the branch material on its parent.

C

Sphere7 doesn’t display a material node because it is inheriting the one from Sphere2.

What are PropertyFixup Groups?

PropertyFixup groups are created automatically by Softimage when it loads a scene and discovers that the same unshared property or material is applied locally on two or more objects. Although this situation should never happen, certain operations in previous versions of Softimage could cause it.

When this situation is discovered, Softimage creates a group called PropertyFixup, adds the objects to the group, and applies the property to the group.

If you load a scene and find a PropertyFixup group, you can:

• Reapply the property the way you want it and delete the group.

• Keep the group (maybe rename it) if you want to share the property.



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