T-H20NEW-004-003

Harmony 20's new Pre-render Cache node provides a way to lighten and speed-up the rendering of complex scenes. You can think of it as a simplified Composite node used to store a cache of rendered frames for selected nodes.

This node can be very useful when working on a scene that contains an element that is extremely long to render, such as a 3D model, a complex special effect or even a scene rendered in 4K.

How to connect the Pre-render Cache node

  1. Do one of the following:

    • In the Node view, press ENTER and use the quick access drop down to search for and select the Pre-render Cache node.

    • In the Node Library, search for the Pre-render Cache node and drag and drop it into the Node view,

  2. In the Node view, connect the Pre-render Cache node between the element you want to Pre-render and the composite. You can give each element its own Pre-render Cache node, or give a group of elements a Pre-render Cache node.

  3. You can connect as many input images as you want to the Pre-render Cache node.

The Pre-render Cache outputs a bitmap image and, contrary to regular Composite nodes, it does not allow vector effects to travel up its node system. Hence, effects such as the Colour Override or the Apply Peg Transformation effects will not work when connected under a Pre-render Cache node.

Properties of the Pre-render Cache node

The Pre-Render Cache node shares some of its properties with the Composite node. Below is a list of the available Pre-render Cache node properties and their use.

Parameter

Description

Enable/Disable

Allows you to enable or disable the node. When disabled, the node has no visible effect on the rendered image, nor on the preview in the Camera, Perspective, Side and Top views.

Colour Swatch

Sets the colour of the layer in the Timeline view, and of the node in the Node view.

Name

Allows you to enter a name for the node.

Input ordering (Requires Cache Rendering)
  • 2D: Elements connected in the node are composited based on their port ordering. The Z-axis (forward-backward) values are ignored. The scaling value will be correct, but the actual position on the Z-axis is ignored.
  • 3D Flat: The Z-axis value of the elements connected in the Composite node are considered, so the visual representation is correct in the Camera view. The output is a flat image.

Output Options
  • Output Z: Identifies which element's front-back value from the current composition is applied to the entire composited image in the next operation. If you select Portnumber, identify the appropriate port by its position using the Port For Output Z menu.
  • Port for Output Z: When using the Portnumber option in the Output Z menu, you can select which port you want to use as the Z value for the Composite node. The port used appears in a bright green colour on the Composite node. By default, the leftmost port is displayed in front and the rightmost port is displayed behind.

Manage Cache
  • All Frames: Select All Frames if you want to pre-render the entire scene.
  • Selected Frames: Select Selected Frames if you want to render a part of your scene. Then, in the field From, type in the first frame of the sequence you want to export, and in the other field, the last frame of the sequence you want to render.
  • Render: Renders the frames into cache images within the prerender.db folder of the current Pre-render Cache node. Those images will be rendered as .rpng files.
  • Clear: Removes every cache image rendered within the prerender.db folder of the current Pre-render Cache node.