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Importing CAD files

Clara.io can import CAD files such as STEP (Standard for the Exchange of Product model data) and IGES (Initial Graphics Exchange Specification).

Import Options

CAD imports can be controlled with various options available in Edit -> Preferences… -> Import -> CAD.

Levels of Details

The first section control the display quality of the objects. Because CAD objects can end up being very large geometry once converted into triangles, it’s possible to import with various level of details (LoD). Because the geometry needs to be downloaded to be displayed, a lower LoD would allow faster loadings and will allow to move the geometry in the scene to create the final scene.

Option Reduction levels, which accepts values between 1 and 6, allows to control how many more LoD should objects have, not counting the original geometry. Reduction levels set to 1* means that the geometry will be half of the quality of the original geometry (and should have relatively 50% of the amount of vertices and faces). Each extra *LoD cuts in half. For example, Reduction levels set to 3* means there will be 4 *LoD: 12.5%, 25%, 50% and 100%. 100% being the non-reduced geometry.

Options WebGL View and Render View allow to control what should be the default LoD to display in the editor and the renderer respectively. The values available for these options are:

• Bounding Box
• Reduced (default value for WebGL)
• Original (default value for Render)
  The Bounding Box is simply a box defines the boundaries of the geometry.

Options WebGL Reduction Level and Render Reduction Level determines which LoD should be used if the View option is set to Reduced. This is a value between 0 and 1. The range between 0 and 1 is split evenly with the number of LoD. Therefore, with Reduction levels set at 3, it means that values:

• between 0 and 0.25 referer to an LoD of 12.5%
• between 0.25 and 0.5 referer to an LoD of 25%
• between 0.5 and 0.75 referer to an LoD of 50%
• between 0.75 and 1.0 referer to an LoD of 100%

Tolerances

Because CAD geometry is not simply defined with triangles, the various faces need to be triangulated to be easily displayed in WebGL.

The following tolerance parameters are available to control this triangulation procedure and the resulting mesh quality:

• Deviation Angle : The tolerated change in angle (in degrees) along a curved surface before a new face is generated. Values from 1-20 are generally adequate.
  • Default value: 5
• Minimum Element Size : A factor determining the quality of relatively small features of a mesh. General parameters used in the triangulation of CAD geometry may not always account well for very small features in very large geometry. This tolerance provides an extra quality boost to such small features. The smaller the value, the higher the quality, so if you notice small features in a mesh having relatively poor quality compared to the mesh as a whole, try reducing this value. Conversely, if you are unconcerned with the quality of very small features in the mesh and wish to reduce the overall size/complexity of the mesh, try increasing the value.
  • Default value: 0.1

In general, smaller deviation angles and smaller minimum element sizes will increase both the quality and data size (polygon’s/vertices) of the generated mesh.

Editor

Once imported, every objects is represented by a binary mesh (named BinMesh).

Level of Details

This allows to control how the mesh is displayed in the editor (WebGL) and the renderer. The default values are defined in the Preferences described above. It’s possible to change the LoD of a specific object to see how it looks at different level of qualities.

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