GENERATE/PREV.gifGENERATE/NEXT.gif

Point Curve

Point curves are NURBS curves whose points are constrained to lie on the curve.

Tip: Object-level NURBS curves can’t contain surface sub-objects, so you can’t use them as the basis for a full NURBS model. But you can convert the curve object to a NURBS surface object using the Edit Stack button in the Modify panel.

Reference

These creation parameters are the same for both Point Curves and CV Curves.

Interpolation

The controls in this area change the accuracy and kind of curve approximation used to generate and display the curve.

Rendering Controls

You can make curves renderable by assigning them a thickness with these controls. The curve renders as a cylindrical object. Renderable NURBS curves appear when you render a scene using Render; they are not rendered in shaded viewports.surface

Renderable: Turn on to make the curve renderable.

Thickness: Sets the renderable thickness of the curveits circular diameterusing the current 3DS MAX units.

Generate Mapping Coordinates: Generates mapping coordinates so you can apply mapped materials to the renderable curve.

Keyboard Entry for Curves

The Keyboard Entry rollout lets you create a NURBS curve by typing. Use the TAB key to move between the controls in this rollout. To press a button, use ENTER while the button is active.

X, Y, and Z: Enter the coordinates of the next point to add.

Add Point: Adds the point to the curve.

Close: Ends creation of the curve and creates a segment between the last point and the initial point, to make the curve a closed curve.

Finish: Ends creation of the curve, leaving it open ended.

How To

To create a NURBS curve:

  1. Go to the Create command panel and turn on Shapes.
  2. Choose NURBS Curves from the dropdown list.
  3. Turn on Point Curve.
  4. In a viewport, click and drag to create the first point, as well as the first curve segment. Release the mouse to add the second point. Each subsequent location you click adds a new point to the curve. Right-click to end curve creation.

    5. Note: If you begin the curve by clicking without dragging, this also creates the curve’s first point. However, if you release the mouse more than five pixels away from where you initially pressed it, this creates an additional point.

    While you are creating a NURBS curve of either type, you can press BACKSPACE to remove the last point you created, and then previous points in reverse order.

    As with splines, if you click over the curve’s initial point, a dialog appears asking whether you want the curve to be closed. Click No to leave the curve open, Yes to close the curve. (You can also close a curve when you edit it at the Curve sub-object level.) When a closed curve is displayed at the Curve sub-object level, the initial point is displayed as a green circle, and a green tick mark indicates the curve’s direction.

  5. Adjust the curve’s creation parameters.
  6. (Optional.) To add a new NURBS curve sub-object, you can turn off the Start New Shape check box, and then repeat the preceding steps.