In computer graphics and video images, the pixel resolution is the number or pixels in the display. Resolution describes the detail an imageholds. The term applies equally to digital images, film images, and other types of images.
Importance of Pixel aspect Ratio for Texture.
Most digital imaging systems describe an image as a grid of very small but nonetheless square pixels. However, some imaging systems, especially those which must maintain compatibility with Standard-definition television motion pictures, define an image as a grid of rectangular pixels in which the width of the pixel is slightly different from that of its height. Pixel Aspect Ratio describes this difference.
Use of Pixel Aspect Ratio mostly involves pictures pertaining to standard-definition television and some other exceptional cases. Most other imaging systems, including those which comply with SMPTE standards and practices, use square pixels.
Pixel aspect ratio 1:1
Pixel aspect ratio 2:1
Any rendering of geometry-based graphics to an image, including text, must take the pixel aspect ratio into account; otherwise it will come out "stretched" or "squished" and blurred due to video quality with non-square pixels. So in the early days of CG, it was important to create a standard that would set the way forward.
So keeping within the 0>1 ratio makes everything a lot easier, as well as keeping texture map dimension either square or dimension to power of 2. E.g. 1024 x 512, 512 x 512, 512 x 256, etc. This can even apply to something like color depth as well.
Resolution vs. Time
While doing rendering map resolution has to be noticed. If map resolution is very high, then rendering take lot of time. If map resolution is more 4k or 6k, then rendering will take more time. To save rendering time, many times low resolution maps are textured on distance objects in scene. Middle object medium resolution Texture & camera near objects are textured with high resolution maps. While rendering sometimes jitter is seen, that time texture resolution has to be check properly, wherever jitter is seen that place sharpness should be reduce.
Unwrapping technique for Texturing
Unwrapping technique of texturing helps to avoid problems of stretching or blurring of textures but in this case also we have to be careful that texture or map should be of appropriate resolution and size. If unwrap is not proper then texture can look stretched though texture is of high resolution. To avoid stretch, uvs has to be opened equally. Sometimes if model is not proper, & if model loops are not proper, then also texture can be stretched. During Skinning process of model if skinning is not proper then also texture can be stretched. All this has to be noticed while doing texture.
These days there are number of software’s (like ZBrush, Deep Paint3D) helps to paint 3D Objects surface directly. Later this surface is exported as unwrapped texture map with uvs. Advantage of these software’s are that they give freedom to artist to paint, shade at any resolution level and export texture without stretch, blur or distortion.
A procedural map is generated by a mathematical algorithm. Consequently, the types of controls you find for a procedural map vary depending on the capabilities of the procedure. A procedural map can be generated in either two or three dimensions. You can also nest texture or procedural maps within another procedural map to add depth and complexity to the material.
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