Evaluate > Surface Evaluate

Creates curves-on-surface corresponding to highlight lines produced by light sources.

Highlights Control

Light Origin: The 3D coordinates of the origin of the first light (center point).

You can set the origin with the highlight manipulator when you use the tool.
Direction Type: Select either Rotation or Vector.
Light Direction: The direction in which the light sources point.

You can set this vector with the highlight manipulator when you use the tool.
Number of Lights: The number of lights from which to create curves-on-surface highlights.

If you use more than one light, the multiple lights are always parallel to each other.
Light Width: The width of the single light source. This option is only available if Number of Lights is 1.

Set the width to 0 to create a single curve-on-surface. Set the width greater than 0 to create two curves-on-surface corresponding to the edges of a wide highlight.

This option has no effect if Visual is turned on.
Light Spacing: The spacing between multiple light sources. This option appears when Number of Lights is greater than 1.
Vector/Plane/Point: Enter the name of a point/vector/plane to position/align the Surface Evaluate manipulator with it. (You can also click a point/vector/plane to align the Surface Evaluate manipulator with it. Or you can select the point/vector/plane and the surface before selecting the tool.)
Subdivisions: The quality of the curve-on-surface projection, from 1 to 6. The higher the value, the more precise the result. Use low values for draft quality, use higher values for final results.
Visual: Draw fast polylines instead of curves-on-surface.

These lines are mainly for display purposes. Although you can pick them (to delete them, for example), you cannot use them to create geometry.
Tolerance: When Visual is checked on, this value defines the quality of the visual curves independently of the tessellation tolerance. This lets you set the visual tolerance to a smaller value to get better quality visual curves, without reducing the tessellation tolerance used for shading.
Left: visual tolerance = 0.1 mm. Right: visual tolerance = 0.001 mm

Control Options

Create History: Save the history of the new curves-on-surface for later editing. If you turn Create History on, you can modify the surfaces and the curves-on-surface update.
Auto Recalc.: Update the curves-on-surface as you change the values in the window.

Buttons

Recalc: When Auto Recalc. is off, use this button to update the curves on surface to correspond to the current options.
Undo All: Undo all the changes made by the tool and return to the original surface.
Next: Finish creating curves-on-surface on the current surface and prompt for a new surface to evaluate.