 SPLIT                                                              Menu: PEDIT
 ==============================================================================
 Sections a solid entity on a plane, keeping both parts.

         1. (CHAR) option: plane: (o-orthogonal, d-diagonal, f-free) <o>
      if option `o' is selected:
         2. (CHAR) axis of section (x,y or z)
         3. (CHAR) define the section by: v-value, p-point <p>
      if `p' is selected:
         4. (POINT) point on section plane
      if `v' is selected:
         4. (POINT) value on axis
      if option `d' is selected:
         2. (POINT) first point on section plane
         3. (POINT) second point on section plane
         4. (POINT) pick point on first cut entity
         5. (POINT) pick point on second cut entity





      if option `f' is selected:
         2.   (POINT) first point on section plane
         3.   (POINT) second point on section plane
         4.   (POINT) third point on section plane
         5.   (POINT) pick point on first cut entity
         6.   (POINT) pick point on second cut entity
      for all options:
         7. * (IND) entity to be split
         8. * (Y/N) confirm choice
         9. * (Y/N) keep the result ?

 Description:
 This command sections a solid entity along a plane, keeping both parts of the
 entity.
 You have the option to section the entity in three ways:
 1. orthogonally at a specified coordinate value (option `o', the default)
 2. perpendicular to an axial plane (xy, xz, or yz, option `d')
 3. by a free plane defined by three points (option `f').




 For option `o':
 Specify an axis along which the entity is to be sectioned. Then select either,
 `p' (default) to point to the position of the section, or `v' to state
 a coordinate value on the selected axis. The section plane will be normal to
 the axis at the specified value.
 For option `d':
 Pick two points on one of the axial planes (xy, yz or xz). The section will be
 cut through the two points perpendicular to the plane on which the points are
 located. Pick another two points, one on each side of the split plane.
 For option `f':
 Pick three points to define a free plane. Pick another two points, one on each
 side of the split plane. For all the points, indicate (and confirm) the entity
 to section. The two new parts of the original entity will be displayed
 temporarily. You are asked if you want to keep the result or not. Entering `y'
 causes the temporary entities to become permanent new entities. You are then
 prompted to indicate additional entities to be split until you enter a new
 command.
 The result of this process is a complex solid entity (data type 9). A wall
 sectioned using this command keeps the axis of a wall entity to enable some
 wall commands such as \oplac, \apsel, etc. Other wall commands (such as \chaw,
 \fixw, etc.) can no longer be applied. This command works only on walls and
 solids. You may not section lines, arcs, texts, or dimension lines.
 When indicating an entity to cut:
 1. A wall entity must be indicated by pointing to its axial line.
 2. A solid prism or any solid created by two polygons must be indicated by
    pointing to one of the edges connecting the polygons.
 3. A complex solid (data type 9) may be indicated by pointing to any of its
    edges. You are prompted to indicate another entity to be split (by the same
    defined plane), until you enter the next command.
 If the split result is illegal, the following prompt will appear:
 result is not a solid; press <ENTER> and the original solid will be redrawn on
 the screen.

         Example: \split o z v 1 (indicate) y y

 Result: The indicated entity is sectioned along a plane normal to the z axis
 (parallel to the xy plane) at the point where z=1. Both parts are kept.
