When selecting the Conic option () inside the Segment Type frame, you will be presented with the panel shown in the image below. Note that the options common to all curve types have been discussed in the Draw Curves landing page. Here, we will discuss only the options that are unique to the Conic segment type.
Conic segments are true conic sections defined by exactly three points. The first two points are the ends of the conic and the third point, the Shoulder, will lie on the interior of the conic between the first two. Alternatively, the third point can define the conic’s Tangent Intersection. Change the role of the third point using the commands in the Conic Segment Options frame, Shoulder or Tangent Intersection. In both modes the tangent lines and their intersection are displayed for reference. Additionally, the conic's ρ (rho) value can be adjusted using the provided text field.
Note: The Slope Guides checkbox becomes enabled only when the Tangent Intersection conic segment option is selected.
When the Tangent Intersection conic segment type is selected, the Slope Guides option allows you to ensure that the conic curve being created is tangent/orthogonal to an existing curve or normal to a database surface. With the option checked on, the slope at any control point shared between the new curve and an existent curve, can be adjusted to make the new curve either tangent or orthogonal to the existent curve at that point. Additionally, if the existent curve sharing a control point is constrained to an underlying database surface, the new curve could also be made normal to the surface at that point.
In order to adjust the slope of the new conic curve at shared a control point, make sure the Tangent Intersection conic segment option is selected, and simply select and drag the tangent intersection handle as shown in the image below. Note that slope guides tangent and orthogonal to the existent curve at the shared point's location will be shown in the Display window. Moreover, in the case of an existent curve that is constrained to a database surface, an additional guide normal to the surface at the shared point's location will also be shown. The guides are color-coded broken lines (see image below). Dragging the tangent intersection handle near the proximity of one of the guides will lock the cursor motion in the preferred location and highlight the entity providing the selected slope.
In the image below, a new conic curve (New Curve in yellow) has its two control points shared with other existing curves (Curve 1 and Curve 2); one of the existing curves is constrained to an underlying database surface. The top portion of the image (Step 1) shows the initial state of the new conic curve before its slope at the shared control points is adjusted. The lower portion (Step 2), shows the final curve being orthogonal to the Curve 1 at the control point Pt1 and tangent to the Curve 2 at point Pt 2.
Tip: In the example shown below, note that in order for the tangent point defining the conic to be made orthogonal to Curve 1 at the control point Pt 1 and tangent to Curve 2 at the control point Pt2, the orthogonal and tangent lines at Pt 1 and Pt2 need to intersect in 3D space.
Note: Source curves do not provide slope information. This means that slope guides will not be available when creating a new curve (connector, database, or source) that shares any of its control points with an existent source curve.