Working with Clip Files
What are Clip Files?
Clip files are a way to collect nodes together so you can use them again and again in projects. The name comes about because the files are a bit like "clippings" from a newspaper. The nodes in the clip file are a smaller part of a whole project like a clipping from a newspaper is a smaller part of the whole page.
Let's say you've set up a shader network with a rock texture that you really like. If you save the nodes making up the rock texture as a clip file you can use it again by inserting the clip file into another project. Clip files are also an easy way to share nodes and node networks with others. You can save any nodes in clip files. They don't have to be connected or related to each other in any way.
Much like project files any assets used by the nodes in a clip file aren't saved in the clip file. As an example you might save a clip file containing an Image map shader. If you wanted to send the clip file to someone else you would also need to send the image used by the Image map shader or they wouldn't be able to reproduce your results.
Creating Clip Files
To create a clip file you first need to select the nodes you want to save in the network view. You can then save a clip in two ways. The first is to context click in the network view and choose "Save Nodes as Clip File..." from the context menu. The second is to choose "Save Nodes as Clip File..." from the File menu.
When you do this the Create Clip File dialog will open. The Create Clip File dialog is described in more detail here. You should read that page as this description doesn't completely describe it.
There are two basic things you can do with the Create Clip File dialog. One is to add information about the clip. You can add a description of the clip. There is a separate field for connection tips. You should add any hints or tips here that might help others (or remind yourself!) to connect the clip nodes into the node network. You can also add tags for the clip. This information can be seen in the Library window as well as in file previews in Explorer (pending for Windows) or the Finder.
The other important aspect of the Create Clip File dialog is that it lets you set input and output connections for the clip nodes. This allows TG to insert the clip into the node network automatically, without the user needing to make connections themselves. When the dialog opens the Input and Output connection settings are initialised with TGs best guess at what those connections should be. You can also use the popups to change the connections or say the clip shouldn't have a connection.
Related to this is the clip Category, which is set using the popup at the top of the dialog. A clip file which has a category can be automatically inserted into the appropriate part of the node network if no connections are specified when it's inserted. For example if you have a clip with the Terrain category it'll be inserted in the terrain part of the network just as if you were adding a new terrain from the Add Terrain button in the Terrain node list. This can make it much easier for people to use the clip as they don't have to guess where it should inserted.
When you've finished setting up the clip file click the "Create Clip File..." button to save the file. Saved clip files will be added to the Library automatically, although this behaviour can be turned off in the Library preferences panel.
You can add a preview to a clip file in the Library window. Select the clip file and then click the "Add preview" button in the Library Info panel and select "Choose preview image file". Adding a preview to the clip file saves the preview into the clip file itself, so if you send the the clip to someone else they will be able to see the preview too. If you want to remove a preview from a clip file you can choose "Remove preview image" from the "Add Preview" button.
Adding Clip Files to a Project
Adding a clip file to a project is known as "inserting" it. There are various was you can insert a clip file into a project. The basic way of doing it is to choose "Insert Clip File..." from the File menu. You can also choose "Insert Clip from Library..." which opens a Library window showing all the clips in the Library. When you insert a clip this way TG will try to insert the clip into the network automatically, depending on the category and connection settings in the clip.
You can also specify where a clip is to be inserted using the node network. When you context click on a node in the network there'll be an "Insert Clip File..." item which allows you to choose a clip file to insert. TG will try to insert the clip into the network depending on where you context clicked.
If you clicked on the body of the node the clip will be inserted in between the node you clicked on and the node its output is connected to. The node you clicked on will be connected to the clip input. The output of the clip will be connected to the node that's connected to clicked node's output (if any). If the clicked node has multiple output connections then the output of the clip will be retain those connections.
If you click on a node input there's a different behaviour. The clip will be inserted into the connection between the node input and the output of the node it's connected to (if any). The output of the clip will be connected to the clicked input. The input of the clip will be connected to the output of the node that was connected to the clicked input.
To sum up, clicking on the node body will insert the clip into the network below the clicked node. Clicking on a node input will insert the clip into the network above the clicked input.
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.
A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.
Context clicking shows a contextual menu. On Windows this would normally be done with a right click. On OS X this could be a control-click or a right click.