Smooth control points works exactly the same as straighten controls, except now instead of straightening the control points Maxsurf now projects the control points onto a smooth curve or smooth patch. Smooth control points moves the control points in all directions and cannot be restrained to one working plane.

 View a video that demonstrates the use of the Smooth Controls command to smoothen out the hull surface of a trawler. [Web | Disk]

Smoothen a curve

Ø  Open the BasicFairingSpline_Start.msd file in Profile view

Ø  Switch Compress view on and set your porcupines size to 50% from the Edit | Preferences dialog.

Ø  Select control points A and B as below

Ø  Use the Controls | Smooth controls | Flexible

Flexible

Ø  Undo the last command and now use Smooth Controls | Medium on the same selection of control points:

Medium

Ø  Undo the last command and now use Smooth Controls | Stiff on the same selection of control points:

Stiff

You notice that, especially when you smooth the control points to a Stiff curve, any irregularities in the curvature (eg inflections) disappear. Now let’s apply this to a patch of control points.

Smoothen a surface patch

Ø  Open the BasicFairing_FairingToolsSmoothStart.msd file in Perspective view

Ø  Switch on Longitudinal Curvature rendering

We will use the Smooth Controls command to fair this model.

Ø  Select a fairly large patch by selecting control points A and B as shows below:

Ø  Use a Smooth Controls | Medium and render the model:

Longitudinal curvature rendering after a smooth control points

It is very difficult to explain and/or learn how the smooth control points command works. Best way to learn about this command is by trial and error; aided by the following tips:

§   The larger the number of control points in the selection the better

§   Use medium first and evaluate the result. Use Stiff in case you need more drastic correction or use Flexible if Medium changed the model too much.

§   Stiff, Medium and Flexible may give the same result depending on the surface stiffness and the number of selected control points.

§   You cannot use the smooth command on a selection with only 3 control points

§   Good results can be obtained by using overlapping patches:

This is an example only, individual patches would have to be bigger for good results

§   Switching between smoothing just one row or column and smoothing a patch can give good results

§   Best results can be achieved when all of the above is used in combination with manual control point movements.

Exercise:

Ø  With the model from this section, experiment using the Smooth Control Points command.

Ø  Use what you have learnt so far to fair your design that you created yourself “from scratch” earlier on in this training manual.

Continue reading the Control point net & surface stiffness guidelines section.