Power Box Quick Help

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The Power Box tool provides a convenient way to create a spline cage that consists of 6 Rail Sweep surfaces. The initial shape is a box. The shape of the box can be modified by editing the points and curves of the associated spline cage sketch or using the Sub-Object Point or Sub-Object Curve editing on the Power Box object itself.

Note that the modification of the Length, Width and Height will reset the spline cage to the shape of the box and loose any edits done on the spline cage. Once you have modified the spline cage, you can change the number of segments without resetting the box shape because the new spline cage is generated using the existing surfaces.


1) Create the original box shape using click/drag/click just like the Max Box.
2) Adjust the length/width/height as necessary.
3) Adjust the Segment Counts (typically you will start with a low number 2 or 3 to get a rough shape going first and then adjust to higher numbers to refine the shape more)
4) Either edit the corresponding spline cage or use "Sub-Obj Point" or "Sub-Obj Curve" editing to modify points and curves. Don't worry about pulling the box apart, the edges share vertices so it is nearly impossible to create something bad.


1) You can use "Shift-Ctrl" to select a loop of edges around the box.
2) We find Scaling useful for doing symmetric operations on either side of the box.
3) It is sometimes convenient to hide the Power Box and edit the spline cage directly.
4) Note that the spline cage is attached to the box and can not be moved on it's own.
5) Start with a small number of curves to get the basic shape and then increase the number to add more detail.

  Power Box Parameters  

Length: Size of the Box in the X direction of the local coordinate system (LCS)

Width: Size of the Box in the Y direction of the LCS

Height: Size of the Box in the Z direction of the LCS

  Spline Cage Settings  

Spline Cage Type:

  • Smooth Bezier Curves: the Bezier points will all be "Smooth"

  • C1 Bezier Curves: the Bezier points will all be "C1 Bezier Points"

Length/Width/Height Segs: specifies the number of segments in the X, Y and Z direction. Note that the number of segments is one less than the corresponding number of curves.

Z-Axis Symmetry: specifies that a symmetry will be applied at the local Z-Axis about the X Y plane. Note if you apply symmetry, you should not move any of the points on the X, Y plane off the plane.

  Edge Rounding  

Rounding Turned On: This is a short cut to turn on "Step Back Blending" in the "Power Surface Parameters" panel. Turning this on, sets the blending to "Blend Corners" and the cross section type to "G2 Blend Section" in that dialog. If this is on a blend will be put between all edges and at the corners. If symmetry is turned on, it will also blend the connection between the symmetric pieces.

Round Size: This is a short cut to modify the Step Distance% in the "Power Surface Parameters" panel.