It increases the polygons count without significant improvement on the visual aspect. Max length : Used to control the maximum length of a polygon (edge).įor a rendering usage, it is often recommended not to use the "Max Length" parameter.This provides more precision on small radius fillets.Īdjust the "Max angle" parameter to keep enough polygons in high curvature areas whose radius is lower than the "Max Sag" value, like fillets for example. Max Angle : The maximum angle allowed between normals of two adjacent polygons (on the same face).The distance values are expressed in millimeters. This parameter ensures that the mesh is similar enough to the original analytical CAD surface (exact geometry).Ī low value means that a very fine mesh is created. Max Sag : The maximum distance between the geometry and the tessellation (also called "Chord error").Several parameters are used to control the tessellation (see the function dialog box), the most important ones being: TIP Want to learn more about the process of tessellating CAD models? Have a look at this keynote ! The "Tessellate" function is available from the "CAD" menu. Pixyz tessellation algorithm has proven to be very efficient at transforming any CAD model into meshes, ready to be displayed and exported, with a perfect balance between visual quality and polygon count. The tessellation step is very important in Data Preparation as it defines the maximum quality of the CAD model. The more triangles used to represent a surface, the more realistic the rendering, but the more computation is required. A mesh is composed of multiple connected polygons, or triangles (1 polygon generally equals 2 coplanar triangles), forming a discretized geometry that is understandable by a GPU, to be rendered in a 3D application. To be displayed in a 3D application, CAD models' faces need to be translated into tessellated surfaces, also called meshes. Opponents note that they cannot technically meet the strictest definition as they are not polygons.NOTE Have a look at About 3D Models Types to understand the difference between CAD models and Polygonal models Similarly, some geometrical artists and mathematicians believe that repetitive patterns involving circles and other curved shapes should be considered tessellations as well. Escher and Robert Fathauer to great aesthetic effect, demiregular tessellations are not considered by most mathematicians to be true tessellations. The above pattern would always be described as a “3.4.6.4” tessellation, and never as a “4.3.4.6.”Īlthough widely used by artists such as M.C. When describing a semi-regular tessellation, always start with the shape that has the smallest number of sides. No matter which point is chosen, the description will be the same: “3.4.6.4.” Choose a starting point, and count the number of sides on each shape that meets up with it. Let’s take a look at a slightly more complicated example to illustrate the point.Ī semi-regular tessellation that uses triangles, squares, and hexagons to create a more intricate pattern will still have the same repeating shapes in the same order around each vertex. They may look more complex, but they still follow the same rules. The same principle is used to describe semi-regular tessellations. So, for example, a regular tessellation that uses only hexagons can be named a “6.6.6” tessellation one that uses only squares or rectangles would be a “4.4.4” tessellation, and one with only triangles could be labeled a “3.3.3.” As noted above, the pattern will be the same no matter which vertex is chosen. Tessellations can be named by listing all of the polygons surrounding a vertex according to how many numbers are in each of them. All together there are eight semi-regular tessellations. However, there are only three types of regular polygons that can be used to form regular tessellations: triangles, squares, and hexagons.Ī semi-regular tessellation is made up of regular polygons as well, but instead of using just one repeated polygon it uses two or more of them to form a more complex pattern. In general, regular polygons can have any number of sides from three on up. Regular polygons are 2-dimensional shapes that have identical angles and sides. This type of tessellation is created using repeated regular polygons. What exactly does all that mean, though? Let’s take a look at some examples to find out. What both of these broader categories of patterns have in common is that the shapes surrounding each vertex, or meeting point, are identical, and it must be possible to repeat the pattern indefinitely without leaving any gaps, or causing any overlaps. All true tessellations fall under one of two categories: regular, and semi-regular. Tessellations are geometrical patterns that can be fit perfectly together and be repeated indefinitely.
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