The Composite node allows you to use several images and output a single image. You can compare that to doing pre-compositions in editing software. You can connect several drawing, image generators and effect nodes in your Composite node and one bitmap (or vector in some cases) comes out of it.
By default, the image resulting from the Composite node is a bitmap. The layers are composited together depending on their position on the Z-axis (forward-backward) first, then their order in the Composite node. If two images are at the same position on the Z-axis, their order in the Composite will determine which one is displayed in front and which one is displayed behind.
For more information about the Composite node options in a 3D environment context, refer to Managing a Node System with a 3D Scene Setup.
As Bitmap: Composites all images into a single, flat bitmap image. The Z value of the final image is based on the Output Z selection.
As Vector: Composites all the images as a single vector image. The Z value of the final image is based on the Output Z selection. Bitmap elements are ignored and do not appear in the final frame.
As Seamless Bitmap: Composites all the images into a single, flat bitmap image (just like the As Bitmap compositing mode). The main difference between the As Bitmap and As Seamless Bitmap modes is that the seamless version ensures that there is no visible seam between adjacent vector drawings that have matching geometries. This can be useful for cut-out animation, where multiple drawings may align perfectly like pieces of a puzzle (using masking/cutter). This can also be useful when building a 3D set out of flat drawings rotated in 3D. In this case, using the Seamless mode will produce the correct result when two drawings are intersecting or nearly intersecting. When using this mode, the following effects are not supported: Shadow, Glow, Blending and Focus.
Pass Through: No compositing operations occur. No image is merged or flattened. Each individual image keeps its own properties. The compositing operations happen only in the next Composite node connected below. In this case, the port ordering is ignored.
If a Composite set to Pass Through it is the last one in the compositing chain, it will act the same as the As Bitmap option. At that point, the Input Ordering options are considered.
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.
You can use the 2D composite type to create effects such as a camera recording overlay on your scene. Since you always want this element to be in front regardless of the other elementsè Z-axis position, you can set the option to 2D.
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.
3D: 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 image is not flattened. The 3D aspect of the elements are kept. For example, if you rotated elements on the three axes, the information is retained and elements composited in lower levels are able to intersect with the elements coming from a 3D Composite node.
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.
These options are active when you select the As Bitmap mode.
Apply Focus: Activates the Focus effect for this node in the composite operation.
Focus Multiplier: The value entered in this field is used as a multiplier for the radius value specified in the Focus or Focus-Multiplier nodes.
These options are active when you select the As Vector mode.
Palette Name: When you render files using As Vector Composite nodes, use this field to set the name of the palette files that Toon Boom Harmony will create for them.
Flatten: Flattens vector drawings into one vector drawing file. Any transparency will be lost in the process. This creates smaller vector files, but might increase the time required to composite the drawings. This can be useful when reusing drawings. Because they will be vector files, you can still apply vector-based transformations and effects.