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.

• Constant number of polyhedral points
  Enter the number of polygon points (min. 2). The default setting is 6.
• Variable  number
  Enter the absolute precision for the polyhedral approximation.
• Variable  number with lower limit
  Enter the absolute precision for the polyhedral approximation and the lower limit for the number of polygon points.
• Variable number with upper limit
  Enter the absolute precision for the polyhedral approximation and the upper limit for the number of polygon points.

The Variable number ... 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. "Lower limit" means that the calculated value must not be less that the entered value; "upper limit" 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!

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 adjoining 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.

 Related Topics

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