By centering the dataset at the origin the numerical precision is maintained to a higher degree. A single precision floating point number can only represent 6 digits, so vertex coordinates such as 1000000.12345 will get truncated to 1000000.0 due to numerical limits. This is the default because many ESRI shapefiles are located very far away from the origin, such as 1 million units away.
If this checkbox is enabled then the model will be re-centered at the origin. Hence, enable this option if the dataset does not view properly in a downstream 3D program.
Also, most DirectX and OpenGL realtime displays will not show the shapefile correctly unless it is triangles or quads. Most 3D file formats can only handle polygons with a maximum of 3 or 4 vertices.
ESRI shapefiles often have concave polygons with dozens or hundreds of vertices. If this checkbox is enabled then all polygons will be triangulated prior to import. This will ensure that the best numerical precision is maintained. In general terms, you should scale the model so that it fits in a bounding box of 1x1x1 to 10000x10000x10000 units. Values greater than 1.0 will scale the model larger, while values less than 1.0 will scale the model smaller. This type-in box allows the relative size of the imported dataset to be scaled. The default angle is 45 degrees higher values will make the surface smoother. If the angle between two adjacent polygons is greater than this number then no smoothing will occur (a crease will be evident between the two polygons), else smoothing will occur where the polygons meet. This type-in value sets the cut-off smoothing angle (in degrees) used by the vertex normal computation algorithm. NOTE: for this option to work properly the input data must have its vertices welded together so thatĪdjacent polygons share the same vertices (the 'Weld Vertices' checkbox must be enabled (check-marked)). If this checkbox is disabled (un-checkmarked) then no new vertex normals will be created. The smoothing criterion is based on the angle between adjacent polygons common smoothed vertex normals willīe computed if the angle between their geometric surfaces normals is less than the 'Smoothing Angle' This option, whenĮnabled, will allow smoothed vertex normals to be computed for the data based on the angle between stl files do not contain vertex normals and thus will not look smooth when shaded. Should be set to 0.00015 (which is the default).Īll. stl file should be shorter than 0.00015 units, the minimum value for this threshold value If the distance between two vertices is less than or equal to this number, and the 'Weld Vertices Together'Ĭheckbox is check-marked (enabled) then the two vertices will be collapsed (welded) into one. Large number of vertices since every vertex must be compared against every other vertex (an n-squared Also, the welding operation can become quite slow for objects with The dialog box This welding operation should be performed if the 'Create Smoothed Vertex Normals' Vertex welding collapsesĪdjacent vertices which are within a distance less than or equal to the threshold value specified on To overcome these problems the 'Welding' option can be enabled (check-marked). stl data to be 'smoothed' out using the smoothing option described below. This is quite inefficient andĪlso it will not allow the. Share vertices even if two adjacent polygons are situated side by side. stl file are, by nature, completely separate from each other and do not If this checkbox is enabled then the import converter will print out the number of objects and polygons that were parsed from the file. Report Statistics About the Geometry File These options control how the imported geometry is processed before it is sent to the NuGraf/PolyTrans Simple vector data elements, most often used for GIS datasets and GIS flat maps. The ShapeFile format was defined by Environmental Systems Research Institute, Inc. The 'Center at origin' option to 'on' so that higher numerical precision can be attained. Large-unit shapefiles exceed the single floating point precision of 6 digits. For single precision floating point file formats (which is most 3D file formats), these NOTE: The ESRI shapefile data is often located very far away from the origin, such as 1 cshp file then load that file only, else load in each. cshp (ESRI ShapeFile project file, which makes reference to other. These files are often created using ESRI's ARC/INFO, ARC/VIEW and ARC/GIS. This geometry import converter reads in the point, line and polygon-area geometrical vector data from a ESRI "Shape File". You are here: Home » Import CAD Formats » ESRI ShapeFiles
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