Skew Deformation

Calling the command:

In the skew deformation, the deformation function is specified by displacing the vertices of the bounding box of the given body. The bounding box is calculated with respect to the axes of the global coordinate system or additionally-specified LCS.

The offset of vertices of the bounding box can be realized along any axis of the coordinate system (the axis with respect to which the bounding box is constructed), along the edges of the bounding box, along the face diagonals of the bounding box. For specifying the offsets in the command, the manipulators as well as the command's parameters window can be used.

The magnitude of the vertex offset for a bounding box can be specified both in absolute units – units of model and in relative units – in fractions of length (in percents) of the bounding box along the respective axes. The relative coordinates can be used in cases when it is necessary to preserve proportions of the deformed model no matter what changes in the source operations are made. For example, the picture below shows how the deformed model will be modified when changing the length of the source extrusion depending on in which units the offsets of the vertices of the bounding box have been specified.

The vertices of the bounding box can be snapped to the 3D points. In this case the offset does not depend on modification of the deformed body or on what units of length have been chosen for specifying the offsets.

When attaching the vertex to a 3D point, the offsets of the vertex with respect to the selected 3D point can be specified additionally.

Creation of Skew Deformation

For specifying this deformation it is necessary:

1.Select a body to be deformed;

2.Define LCS for the bounding box calculation (optional step);

3.Define LCS for offsets calculation (optional step);

4.Select fixing points for bounding box's vertices (optional step);

5.Specify the required offsets of the vertices of the bounding box;

6.Complete the operation creation by pressing .

Selection of Deformed Body and LCS of Deformation

For selecting the deformed body, the following option of the automenu is used:

This option is turned on by default upon the entry into the command. The deformed body is selected with the help of in the 3D window or in the tree of the 3D model. The selected body is highlighted, and the contour of the bounding box appears.

By default the bounding box is calculated with respect to the axes of the selected operation's coordinate system. It is possible to switch between bounding box based on global LCS and based on LCS of the selected operation using the following automenu options, which are grouped into a drop-down list:

Upon switching an LCS, the bounding box is automatically recalculated in accordance to the new axes orientation.

Specifying Offsets for Nodes of Bounding Box of Deformation

After constructing the bounding box, in the 3D window a user can select the vertices of the box in any order and specify their offsets (with respect to initial position). To specify vertices' offsets, the 3D manipulators are used.

   

By default, offsets are calculated in the same coordinate system as the bounding box. It is possible to select another coordinate system for offsets calculation using the following automenu option:

After choosing the LCS, offsets manipulators are reoriented in accordance to the selected LCS' axes.

LCS selection can be canceled using the following automenu option:

The offsets of the vertices of the bounding box (with respect to their initial position) can be also specified in the command's parameters window. After selecting the deformed body, the list of all vertices of the bounding box will appear in the parameters window. Under the list, there will be input boxes for input of the offset values (the Offset parameters group ). To specify the offsets, it is sufficient to select the desired node-vertex from the list (it will be highlighted in the list and in the 3D window), and specify the offset values along the axes X, Y, Z in the input boxes of the Offset group.

Units, in which the offsets of vertices are specified, are controlled by the status of the Relative Value, % checkbox. By default this checkbox is disabled, and the specified offsets are absolute (i.e., are measured in units of model). If the checkbox is enabled, the specified offsets will be recalculated in relative units.

For fixing a vertex of the bounding box to a 3D point, select the desired vertex (in the 3D window or in the list of vertices in the command parameters window) and turn on the following option of the automenu:

After activating this option, 3D fixing point has to be selected. The drop down list of this option contains filters for selecting various 3D objects capable of defining a 3D point.

For a vertex of the bounding box fixed to a 3D point, the offsets input boxes in the parameters window will remain accessible. The offsets specified in these input boxes will determine the vertex offset with respect to the 3D fixing point. The offsets with respect to a fixing point can be also specified in the 3D window with the help of the manipulators.

To cancel a fixing to a 3D point, select the desired vertex (in the 3D window or in the vertices list in the dialog of the command) and invoke the following option of the automenu

After invoking this option, the vertex is untied from the 3D point. Note that the offset of the given vertex does not change at that. The vertex will remain in the position specified by the 3D point. However, later, when modifying the original model or location of the 3D point, the offsets of the given vertex of the bounding box will be recalculated as if they were specified by numeric values from the beginning.