Node Description and Purpose:
The Plane object creates a flat plane. You can texture it just like any other object. By default the plane is rectangular but you can also shear it so it becomes a parallelogram.
The plane is single sided. This means that it only shows up when you look at it from the "front". If you look at it from behind then the plane becomes invisible.
The plane has quite a detailed preview. To help you size and orient the plane the A edge is drawn in orange and the B edge is drawn in magenta. The other two edges are drawn as dashed lines. The plane also has a full bounding box. If you can see the edges of the plane in the preview but not the plane itself then that means you are looking at the plane from "behind".
The plane is not the easiest object to position. The orientation of the plane is controlled by setting the direction of two of its edges, using the Edge vector a and Edge vector b parameters. Essentially you set the way the plane faces by pointing those two edges in appropriate directions.
When a plane is created it's horizontal with edge A pointing along the X axis and edge B pointing along the Y axis. Lets say you want the plane to be vertical and facing down the negative X axis. Change the Edge vector b parameter to (0, 1, 0). This makes the B edge of the plane point straight upwards, which changes the orientation of plane as shown in the image below.
If you want the plane to stay rectangular then the two edge vectors need to be at right angles to each other. If you change the edge vectors so they are no longer at right angles then the plane shears and becomes a parallelogram.
Node Type: Object
- Visible to camera: If this is checked the plane is visible to cameras such as the render camera. In other words it will show up in renders. If this is unchecked the plane won't show up in renders. However if, for example, the Cast shadows checkbox is checked then the shadows cast by the plane will still be visible.
Visible to other rays: When this is checked the plane is visible to various rays which are traced during rendering, such as reflections, transparency and GI rays. As an example, if this was unchecked the plane would not show up in reflections.
Cast shadows: This should be checked if you want the plane to cast shadows.
Center: This sets the position of the centre of the plane
Length a: This sets the length of the A edge (orange in the preview).
Length b: This sets the length of the B edge (magenta in the preview).
Edge vector a: This sets the direction of the A edge.
Edge vector b: This sets the direction of the B edge.
Surface shader: You can use this to assign a surface shader to the plane.
Displacement tolerance: TBC
The bounding box is a box which surrounds (or bounds) an object or shader. This box shows the maximum extents of the item inside it. Sometimes abbreviated as "b-box".
A vector is a set of three scalars, normally representing X, Y and Z coordinates. It also commonly represents rotation, where the values are pitch, heading and bank.
A parameter is an individual setting in a node parameter view which controls some aspect of the node.
A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.