Info UV Coord. (2D Global)

The Txt_Oper->Info UV Coord. (2D Global) command in the Matter module lets you convert a 2D global projection texture map into UV coordinates on a polygon per polygon basis, which define its geometry. Once you apply these coordinates, you can also edit their values.

By storing texture coordinates to the polygon mesh object's vertices, a texture map is essentially "tacked" to the object's geometry. This means that when you deform an object, the texture map follows its appropriate vertex. For example, if you place a 2D texture map as a label on a jar, map the texture's coordinates to the jar's vertices, and deform the jar's geometry by twisting it, the label moves with this deformation.

This command works best on models with a single texture applied. If more than one texture is applied, it may lead to "confused" textures since each texture expects different texture coordinates, while the texture coordinates used are those stored with the object's geometry.

For automatically applying texture map coordinates to a polygon mesh object, see Polygon->Automatic Texture.

Procedure

1. Select a polygon mesh object and assign a 2D global texture to it (Texture->2D Global/2D Local).
2. In the 2D Texture dialogue box, select one of these Mapping Methods: XY, XZ, YZ, cylindrical, or spherical.
3. Click Ok to save your settings and close the 2D Texture dialogue box.
4. Choose the Txt_Oper->Info UV Coord. (2D Global) command to store the texture coordinates with the object's vertices. You can also use this command to manually edit the actual texture coordinate values for the polygon mesh object's vertices.
   
   The UV texture coordinates editor dialogue box is displayed.
   
   If there are selected polygons on the currently selected polygon mesh object, only the texture coordinates for those polygons are displayed in this box.
   
   
5. Click Ok to accept the default settings for the texture coordinates, or click Cancel to cancel the operation.
   
   If you want to edit the texture coordinate's values, follow these steps:
   
   
6. Select the Browse order: it is Polygon by default, meaning that all the texture coordinates used by the polygon are adjacent in the scroll box. If you select the Vertex browsing order, all the texture coordinates at that point appear in the scroll box, one for each polygon that shares the vertex.
   
   With either browsing order, the scroll box displays the identifying number of each vertex and the polygon to which it belongs.
   
   
7. Select a vertex in the scroll box for editing. In all SOFTIMAGE 3D windows, the selected vertex is highlighted in green, and the polygon to which the vertex is associated is highlighted in pink.
8. The current values of the texture coordinate for the selected vertex are displayed in the U and V text boxes. Enter a value in the text boxes.
9. Apply the changes to the vertex using the Modify or Modify vrtx buttons.
10. The Cancel button undoes modifications while keeping the dialogue box open, even after selecting one of the Modify buttons. Click Ok to accept all settings and close the dialogue box.

Parameters

Name

Name of the 2D texture map you selected in the 2D Texture dialogue box.

Browse Order

The information about the texture coordinates is sorted in two orders: by Polygon or by Vertex.

• Polygon: By default, textures are sorted by polygon, meaning that all the texture coordinates used by the polygon are adjacent in the list. This gives you quick access to all the vertices of a particular polygon.
• Vertex: Lists all the texture coordinates, one for each polygon that shares the vertex.

Scroll Box

The scroll box displays the identifying number of each vertex and the polygon to which it belongs. There are more texture coordinates than geometry vertices because SOFTIMAGE 3D allows polygons that share a geometry vertex to each have different texture coordinates for the shared geometry. For example, with a textured cube, there are 24 texture coordinates shown in the scroll box. This is because each vertex is shared between three polygons, so there are three texture coordinates for each geometry vertex.

When you select the vertex, the selection of the polygon lets you determine to which polygon a texture coordinate is applied: the selected vertex is highlighted in green, and the polygon to which the vertex is associated is highlighted in pink. This is very helpful when editing texture coordinates on shared geometry.

U and V

The current values of the selected texture coordinate are displayed in the U and V text boxes (the W value is not currently implemented). The values can range between 0 and 1. The u and v values are the pixels in the texture map that are used at the vertex. When two polygons share a vertex, but you edit the values for only one of the polygons (at a shared vertex), the pixel in the texture that is mapped onto the two polygons is not the same at the shared vertex. This makes the texture different along the edge between the two polygons.

Modify Vrtx

If you apply a change to the vertex using this button, the change is applied to the texture coordinates of all the polygons sharing the selected geometry vertex. This method of applying changes ensures that the texture is continuous across the shared geometry.

Modify

If you apply a change to the vertex using this button, the change is applied to the selected texture coordinate only. This means that if the geometry vertex is shared, only one polygon texture is modified.

Last updated 02-apr-1998