Overview

ParaView 4 comes with improved support for rendering multi-block datasets. Now, each individual block can have custom rendering attributes such as visibility, color, and opacity. The goal of this post is to introduce the user to the new multi-block visualization capabilities in ParaView 4.

Motivation

Previously, to render individual blocks in different styles in ParaView the dataset would need to be split up into multiple actors. This is both inefficient for rendering and cumbersome for the user. The new functionality allows users to set properties directly on each block and view the result in ParaView’s 3D render view.
Under the hood, new multi-block support was added to VTK’s painter pipeline to manage per-block rendering attributes. The new framework acts like a scene-graph allowing properties to be inherited through the multi-block dataset.

Interface

Multi-block rendering attributes can be modified and viewed through the new Multi-block Inspector panel. Each block is listed in a tree showing the inheritance hierarchy for the dataset along with rendering attributes for the block. By using data-set's natural inheritance hierarchy, large changes to display properties can be made with a single click.

The tree-view also shows the currently selected blocks by highlighting their rows. Changing the block selection either in the render-view or the tree-view will update the global block selection and be reflected in both views. This allows for users to choose blocks in either view (or even both) and get visual feedback before modifying the properties for all selected blocks.

Furthermore, attributes can also be modified directly in the render view through the right-click menu. Simply right-click on a block in the scene and a menu will be displayed allowing the user to toggle the visibility for the block or set individual rendering properties. This menu also considers the current block selection allowing properties for all currently selected blocks to be modified simultaneously.

Conclusion

ParaView 4 provides improved support for rendering multi-block and allows the user to customize display attributes on a per-block basis.