The Effects->Create command in the Motion module allows you to create a wave, which can then be attached to an object to produce a deformation.

Note:

This effect is not currently applicable for NURBS curves.

Procedure

1. Create a curve representing the profile of the wave.
   
   The curve should be drawn in the xy plane, and should not double back on itself. If you create a wave with an invalid profile curve, a warning message is displayed in the status bar. The magnitude of the disturbance is determined by the height (y values) of the profile curve. The portion of the curve with x greater than 0 affects objects as soon as the wave starts to act. The portion of the curve with x less than 0 affects objects as the wave propagates. This part of the disturbance appears to be coming out of the origin of the wave over time.
   
   
2. Choose the Effects->Create command. The Define Wave dialogue box is displayed.
3. Select the type of wave desired (circular, planar, or spherical) and set the parameters as desired.
4. Click Ok to accept the settings or Cancel to cancel the operation.

Parameters

Wave Type

Determines how the wave disturbance propagates from its source. There are three wave types:

• Circular moves out from a point in a circular pattern, like a water drop on a pond.
• Planar moves out from a line in a planar pattern, like a wave on a beach.
• Spherical moves out from a point in a spherical pattern, like an explosion.

Velocity

Determines how fast the wave disturbance propagates through space. Velocity is given in SOFTIMAGE 3D units per second; a value of 10.00 means that the wave moves 10.00 units in 1 second (30 frames).

Acceleration

Determines if the wave speeds up or slows down over time, and if so, by how much. It is measured in units of velocity per second; a value of 5.0 means the waves velocity gradually increases by 5.0 units/second over a period of 1 second. In that case, a wave starting with a velocity of 10.0 at frame 1, has a velocity of 15.0 at frame 31, a velocity of 20.0 at frame 61, and so on. The acceleration can also be negative, corresponding to the wave slowing down (or even reversing direction) over time.

Frame Start

Determines the frame number at which the wave first starts to have an effect.

Frame End

Determines the last frame at which the wave has an effect.

Note:

The wave repeats its effect in a cyclic manner after the end frame if Wave Periodicity is selected, so cycling of the function curve isn't necessary. Do not combine function curve cycling with this command: use one or the other.

Vertical Falloff Start

Determines at what height the wave's effect begins to drop off. The height is measured in SOFTIMAGE 3D units along the y-axis of the wave.

Vertical Falloff End

Determines at what height the wave's effect ends. The height is measured in SOFTIMAGE 3D units along the y-axis of the wave. These two parameters are useful, for example, if a circular wave is positioned at the top of a sphere. By default, the wave affects both the top and the bottom of the sphere, which may not be the desired effect. However, if the sphere has a radius of 5, and the Vertical Falloff Start is set to 0 and Vertical Falloff End is set to 5, the wave does not affect anything below the sphere's midline.

Wave Periodicity in Space

Determines whether or not the disturbance pattern defined by the profile curve extends repeatedly in space. In effect, if this option is selected, the profile curve repeats end to end infinitely.

Wave Periodicity in Time

Determines whether or not the wave repeats its effect over beyond the frame end. It is easy to animate a cyclical effect, such as a faucet dripping into a bowl of water.

Displacement Direction

Determines in which direction the points of an object are displaced. It can have one of three values:

• Wave Up: The points of the object are displaced in the up direction of the wave, which is the y-axis in the local coordinate system of the wave.
  
  Note:
  
  Since the wave can be positioned and oriented like any object, you can modify this direction.
  

• Wave Direction: The points are displaced in the direction in which the wave itself is moving. For example, if you want to make a long thin object sway back and forth, you can create a planar wave with Wave Direction as the displacement direction, then attach it to the object and orient it so that the object's long axis is parallel to the wave's y-axis. If you also want the bottom of the object to remain still while the top portion moves back and forth, then position the wave at the top of the object, set the Vertical Falloff Start to 0.0 and set the Vertical Falloff End to the height of the object.
• Object Normal: A point is displaced in the direction of the normal to the object at that point. This makes a wave appear to be following the contour of an object.

Result

The selected wave icon is displayed. The icon is scaled according to the size of the profile curve. The decay and spread function curves are created and initialized for the wave. They can be accessed through the FcrvSelect->Spread commands. The decay function curve provides an overall scaling factor for the wave amplitude over time (the y values of the defining profile curve). By default it starts at 0, rises sharply to 1, and then decays slowly back to 0. This corresponds to a wave rising rapidly on a surface and then slowly receding back to zero.

The spread function curve gives an overall inverse scaling factor to the x values of the wave profile. For example, a value of 0.5 stretches the profile by 2 in the x direction, which has the effect of spreading the wave. By default the spread function curve is the constant value 1. Certain types of waves, such as a water wave, spread out as they move. For waves, you should edit the spread function curve to start at 1 and end at a smaller value such as 0.5.

Wave Icons

After you create a wave, it is not directly linked to the profile curve used to define it. You can edit or delete the curve without affecting the wave. To change the profile curve of a wave, refer to the Effects->Change Profile command.

Translations and rotations may be applied to the wave icon in the same manner as ordinary objects. The wave's effect on objects changes in the obvious way.

You can apply scaling as well. The icon changes shape accordingly, but the wave's effect on objects changes only in the following ways:

• For scaling in x and y, the effect appears as if the profile curve was scaled correspondingly.
• Scaling in z does not change the effects of circular or spherical waves, but changes the z-extents for planar waves. The planar wave icon makes this very clear.

The Effects->Spread commands.

Procedure

1. Select the wave to be edited.
2. Choose the Wave->Edit command.
   
   The Define Wave dialogue box is displayed as shown for the Effects->Create command.
   
   
3. Select a type of wave and set the parameters as desired.
   
   Refer to the Effects->Create command for a description of the wave parameters.
   
   
4. Click Ok to accept the settings or Cancel to exit the dialogue box.

Note:

All parameters except the wave type can be edited. If the wave's start and stop frames are changed, then the decay and spread function curves are resized and offset to match the new values. Similarly, if the Wave Periodicity In Time option is selected, the extrapolation type of the decay and spread function curves is changed to cyclical (constant).

The Effects->Freeze command allows you to freeze the effect of the wave on an object, keeping the object deformed in this shape.

Procedure

1. Select the wave you want to freeze.
2. Choose the Effects->Freeze command.

The object's points are frozen in their current deformation and the wave is detached from the object. The wave icon remains on the screen, and can be reattached to the same object or a different object.

Note:

Currently, freezing is only implemented for node waves, not for branch waves. The Effects->Freeze command does not freeze the object's transformation, only its current shape. If there are several waves attached to an object, or if there are other effects, such as curve or lattice deformations on the object, these effects are also frozen. This can lead to a doubling of the effects remaining on the object. Removing or detaching the other waves returns the object to its normal undoubled state, since if more than one wave is still attached to the frozen model, they are amplifying their effects to this new object.

The Effects->Change Profile command allows you to redefine the profile curve of an existing wave.

Procedure

1. Create and select a new profile curve either by editing an old curve, or creating a new curve.
2. Choose the Effects->Change Profile command.
3. Pick the wave icon.

The wave icon flashes, indicating the profile curve has been changed.

The Effects->Detach command allows you to detach a wave from an object. The wave icon remains on the screen and may be reattached to the same object or a different object.

Procedure

1. Select the wave you want to detach.
2. Choose the Effects->Detach command.

The wave is detached from the object, and the object is restored to its original geometry.

Note:

The Show->Surface command should work in either case.

Last updated 02-apr-1998