Project: HiCAD Basics

Surface Approximation and Limiting Angle for Shading

• Surface approximation
• Limiting angle for shading

Surface approximation

Drawing > Properties > Attr. > Surface approximation

You use this function to define the number of polygon points for 3-D quadrants. This setting is taken into account, for example, in polyhedral approximation and shading of 3-D models.

• Polygon points per quadrant
  Enter the number of polygon points per quadrant (min. 2, max. 100). The default value is 6. If a value of > 10 is selected, this may cause a performance decrease. HiCAD will therefore issue a warning massage. If you want to suppress this warning message, open the Configuration Editor, choose System settings > Miscellaneous, and deactivate the Display error message during polyhedron approximation? checkbox.
• Via distance tolerance
  Enter a distance tolerance for the polyhedron approximation. The default value is 0.1.
• Via distance tolerance with minimum number
  Enter a distance tolerance for the polyhedron approximation and the minimum number of polygon points. If a value of > 10 is selected for the polygon points, this may cause a performance decrease. HiCAD will therefore issue a warning massage.
• Via distance tolerance with maximum number
  Enter a distance tolerance for the polyhedron approximation and the maximum number of polygon points. If a value of > 10 is selected for the polygon points, this may cause a performance decrease. HiCAD will therefore issue a warning massage.

The Via distance tolerance... functions approximate according to a predefined precision value (default = 0.1). The precision value is used to determine the maximum distance permitted between analytical surface and polyhedral surface. The number of polygon points for 3-D quadrants is then calculated separately for each curved surface using this precision value. With minimum number means that the calculated value must not be less that the entered value;with maximum number means that the calculated value should not be greater than the entered value.

Please note:

• Variable approximation is especially recommended for different fillet radii, which is why the parts should, in principle, be created analytically.
• The setting made here has an effect on the display of shaded models. The higher the value, the cleaner and more exact the shading is. However, it also increases the file size!
• In the Configuration Management under Modeling > Part creation > Polyhedron approximationthe default settings predefined by ISD have been changed as follows:

These settings are well suitable for large drawings.

The settings shown above are also used in the Configuration Templates (CSV files) for mechanical engineering and plant engineering included in the scope of delivery of HiCAD, which are loaded via the Parameter Configuration. The steel/metal configuration template uses 4 division points per quadrant.

Limiting angle for shading

Drawing > Properties > Attr. > Limiting angle for shading

The limiting angle is only relevant to shaded 3-D models, in which curved surfaces may show disturbing colour differences at the polyhedral edges. For all edges in which the adjacent surfaces form an angle less than the specified edge limiting angle, a correction is performed to make the edges look "rounded".

Enter the desired limiting angle. The value must be between 0 and 180 degrees. The specified limiting angle applies to all parts of the drawing.

Example: Edge limiting angle 45°

Example: (1) Edge is retained, (2) Edges remain rounded

If you want to use a different limiting angle for individual parts of the drawing, perform the following steps:

1. Activate the desired part.
2. Use the right mouse button to activate the context menu for parts and select Properties .
3. Select Limiting angle for shading.
4. Specify the limiting angle for this part.

Present 3-D Models • Analytical or Polyhedral Model (3-D)