Tag Properties
Use this setting to define the angle to which two neighboring surfaces should be rounded. To do so, activate the Angle Limit option and enter the desired angle here.
The effect of this function is shown in the example below. A simple cylinder was used as a test object. The image at the left Phong Angle was applied without Angle Limit, in the center Angle Limit was set to 89.5° and the cylinder at the right has no Phong Angle applied.
When calculating smoothed objects, Cinema 4D always assumes the polygons (and their Normals vectors) are oriented uniformly. If they are not, shadow anomalies can occur when the image is rendered. All primitives, though, have a uniform orientation.
When in edge mode, Cinema 4D allows you to break the Phong shading along edges using the Break Phong Shading command (Mesh menu).
The edge breaks in red and the rendered result.
When breaking individual edges, the effect will only occur if the end points of the edge are surrounded by connected polygons (Break Phong Shading – menu). In the following illustration, the effect of breaking will be visible for edge A, but not for edge B.
You can enable or disable the effect via the Use Edge Breaks option.
The following types of Generators object make use of these new Phong features: Extrude, Lathe and Sweep. To see the difference, select the Generator object’s Phong tag and in the Attribute Manager, disable the Use Edge Breaks option. Provided the option is enabled, the edges will be sharp.
Left: Use Edge Breaks disabled; Right: Use Edge Breaks enabled
Click on this button if you want to create a Normal tag from the Vertex Normals currently defined by the Phong tag (see also Normal tag).
If a Normal tag already exists, this button will be grayed out; it will also be grayed out if the Phong tag is assigned to a primitive or a Generator.