Creating 3D Curves

Figure 3:22. 3D Construction Dialog.

Using the Cline curves created from the previous step, 3D lines can be created by projecting the Clines onto the section curves which can be done as follows. Select the icon to open the 3D Construction dialog. The default page is Intersect and will be displayed automatically. From this select the set of orthogonal curves (Sections in this case) the Cline will be projected against by clicking on the Toggle buttons located in the With panel. Normally all 3D curves should be created as Plines initially. A Pline is a 3D curve that generates an ordinary data point when interpolated to generate a section, Therefore, for the Type select Pline. Select the cline to project and enter a Name for the 3D curve. The creation of the pline can be limited. For example, to create a pline only in the aft portion, it would be recommended to set the upper limit to FOS. All intersection points forward of the FOS point will then be discarded. Click the Create button to generate the curve. This will generate data points for the required 3D curve, which can be fit and stored in the usual manner.

Where Plines intersect the FOB or FOS regions the user should sort the data points using a near point sort and select the point nearest midships as the start point. This will ensure that the FOB, FOS regions of the curves remain flat.

Plines, tangents and knuckles created in this way can be regenerated at any time by selecting the curve on the Curve Tree, clicking the Right Mouse button and selecting Regenerate.