Example showing texture discontinuities at a seam. Hence, a 3D artist has to do manual corrections by moving the unwrapped face on the texture until the seams match.įor this reason, seams are often placed in areas which are less visible to the virtual camera. The problem of seams is that they create discontinuities in the texture on the faces.įor instance, if a brick wall texture is applied to a cube, it can happen that the “lines” of brickwork do not match up at the seams. Subsequently, a vertex in the 3D space can be mapped to multiple vertices in the UV-space if the adjacent edges are seams. This means that the faces which are not connected in the texture space. To minimize the stretched textures, edges of the mesh can be marked as seams. This leads to a stretched texture on the cube. In the UV map, the faces do not have the same shape as in 3D. Another UV map which also projects the cube to a texture. A UV map which projects a cube to a texture. Stretching occurs if the shape of a face is distorted in the UV-space.Įspecially curved surfaces like a sphere are difficult to UV-unwrapping without stretched textures. Good UV-unwrappings minimise the amount of stretching. When UV-unwrapping an object, its faces are laid out on the texture. This also means that UV-points are independent of the texture resolution and are scaled with the image. ![]() UV-coordinates range from 0 to 1 with the point (0,0) at the left bottom of the image and (1,1) at the top right. This distinguishes the UV-coordinates which are associated with a texture with points in the 3D room. The 2D texture space is also called UV-space, the two axes are labelled with U and V instead of X and Y. More technical, each vertex of the mesh is mapped to a 2D vertex in the space of the texture and with new connectivity data. ![]() The image texture is applied to this flat representation. Intuitively, the mesh is cut open at some edges so that its 3D shape can be unfolded into a flat form. ![]() The process of creating this mapping is called UV-unwrapping. It defines which texture pixel, also called “texel”, is displayed on the mesh’s face. Since image textures are two-dimensional data, a mapping is needed from the 3D room with the object to the 2D space with the texture. ![]() More details about textures are described in the chapter about Computer Graphics. Textures are images which are applied to the 3D object’s faces, e.g.
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