Command entry:Select a NURBS object.
Modify panel
Create Surfaces rollout
Dependent Surfaces group box
Extrude
Command entry:Select a NURBS object.
Modify panel
NURBS toolbox
(Create Extrude Surface)
An extrude surface is extruded from a curve sub-object. It is similar to a surface created with the Extrude modifier. The
advantage is that an extrude sub-object is part of the NURBS model, so you can use it to construct other curve and surface
sub-objects.
Procedures
To create an extrude surface:
The NURBS object must contain at least one curve.
- In the NURBS toolbox, turn on (Create Extrude Surface).
- Move the cursor over the curve to extrude, and drag to set the initial amount.
By default, the surface extrudes along the NURBS model's local Z axis. A gizmo (yellow by default) indicates the direction
of extrusion. Transforming the extrude surface's gizmo changes the direction of the extrude, letting you extrude along an
axis that isn't aligned with a local coordinate axis.
The Flip Normals control lets you flip the surface normals at creation time. (After creation, you can flip normals using controls
on the Surface Common rollout.)
- Adjust the extrusion parameters.
Interface
While an extrude sub-object is selected, a rollout with the extrusion parameters is displayed at the bottom of the Modify
panel.
Extrude Surface rollout (creation time)
- Amount
-
The distance the surface is extruded from the parent curve in current 3ds Max units.
This parameter is animatable.
Direction group
- X, Y and Z
-
Choose the axis of extrusion. Default=Z.
- Start Point
-
Adjusts the position of the curve's start point. This can help eliminate unwanted twists or "buckles" in the surface.
This control is disabled if the curve is not a closed curve.
The start point is displayed as a blue circle.
- Flip Normals
-
Lets you flip the surface normals at creation time. (After creation, you can flip normals using controls in the Surface Common
rollout.)
- Cap
-
When on, two surfaces are generated to close the ends of the extrusion. While they are present, the cap surfaces are maintained
so they match the dimensions of the extrude surface. The parent curve must be a closed curve.
The Cap check box appears only on the creation rollout. If you want to remove the caps later, simply select them as surface sub-objects and delete them.
Think of extrude capping as a workflow shortcut rather than a property (or parameter) of extrude surfaces.
To flip the normal of an extrude cap, select it as a Surface sub-object and use the Flip Normals toggle on the Surface Common
rollout.
Extrude Surface rollout (modification time)
- Amount
-
The distance the surface is extruded from the parent curve in current 3ds Max units.
Direction group
- X, Y and Z
-
Choose the axis of extrusion. Default=Z.
- Start Point
-
Adjusts the position of the curve's start point. This can help eliminate unwanted twists or "buckles" in the surface.
This control is disabled if the curve is not a closed curve.
The start point is displayed as a blue circle.
- Replace Base Curve
-
Lets you replace the parent curve. Click the button, then click the new curve on which to base the extruded surface.