UV Editor

The UV editing window opens from the 'Windows/UV editor' pull down menu. F11 is the hotkey for opening the window.

With this window, you can edit:

• UV coordinates of NURBS meshes
• UV coordinates and other vertex variables of SDS objects
• UV coordinates of UV Set objects
• Face UV's of SDS objects
• UV coordinates of trim curves

Editing UV coordinates of a SDS sphere

The Popup Menu

The popup menu of the UV editor is context sensitive. Below is a picture of the menu when editing a subdivision surface which has two vertex UV channels and two face mapped materials.

The purpose of these menus are described below.

• Edit: Turns edit mode on/off. Edit mode must be enabled before UV editing can take place.
• Accept, Go Back, Cancel: The standard menus for interaction control.
• Properties: Opens the UV editor property window where various editor settings can be changed.
• Reset View: Resets the windows scale. The window will show exactly the unit square of the UV plane.
• Show all faces: Makes all faces being edited visible. This includes all SDS faces if you are editing vertex UV's. In face UV editing, all faces that have the currently selected material mapped on them become visible. With this and the three following menus, you can reduce excessive UV mesh complexity so that a suitable subset of data is left visible for editing.
• Hide all faces: Makes all faces being edited invisible. After applying this menu, you can make a suitable subset of faces visible with the 'Show selected faces' menu. Note: you can perform the selection in a normal 3D view. Hiding faces in the UV editor does not make them invisible in a 3D view.
• Show selected faces: Makes all faces that are currently selected visible.
• Hide selected faces: Makes all faces that are currently selected invisible.
• Edit Points: Switches the UV editor to edit point handles.
• Edit Edges: Selects editing by using edge handles.
• Edit Faces: Editing with face handles.
• UV coords and my_custom_uv: This menu group shows all UV type vertex variables which are attached to the object. You can change the editing target to one of the vertex variables using these menu items.
• circles and marble: This menu group lists all materials that are face mapped to the selected SDS object. You can select from the menu which face material UV's to edit.
• Detach: Removes the material indicated by the menu group above (marble in this example) from the selected SDS faces.
• Detach All: This menu lists all attached face materials. You can remove the desired material attachment from all faces (regardless of the face selection).

Navigation

The following navigation operations are available:

• Ctrl + RMB dragging (or middle mouse button dragging) pans the UV editor
• Shift + RMB dragging zooms the UV editor in and out

UV Coordinate Types

NURBS surfaces and trim curves have only one UV channel available. Actually a NURBS surface may not have any UV channel at all, but you can attach and initialize the channel using the pull down menu 'Methods/NURBS mesh/Define UV'. When editing this kind of objects, there is no need to select what to edit in the UV editor.

The situation is more complex when editing a SDS object. This object type not only allows several UV channels mapped to vertices, but also supports face mapped materials which have their own parametrization. Vertex UV channels store one UV value per vertex so that adjacent faces share the same UVs. Shared values make this parametrization type automatically continuous over face boundaries.

A face mapped material stores a private UV value for each vertex per face per material. The advantage is that faces can be torn apart in the UV space. A typical disadvantage is that face mapped materials do not run continuously over face boundaries.

UV Editor Backdrop

• The object has a direct UV texture (defined in Property window/Col tab/Texture field). The backdrop is drawn using a maximal accuracy, limitation being the resolution of the UV editor or the texture image itself.
• When editing of a face mapped material of a SDS object is started, the program automatically computes a backdrop image. The backdrop accuracy is defined by the Property window/Wire tab/Texture Quality field.
• You can also drag and drop any image from the select window's image tab onto the UV editor. Note: make sure that you don't have a SDS object selected an in edit mode, because you can assign images to selected faces the same way, too. Alternatively, the backdrop image can be created on the select window and activated using a UV view property window.