UF_DPUD provides the required functions and type definitions for
the creation of drive paths for Surface Contouring

UF_DPUD is used when an operation uses the User Defined drive path
method. When setting up a User Defined drive path, the user must
enter the name of an environment variable which points to a usable
shared library. The Surface Contouring processor expects a single
entry point, dpud(), in this shared library to service
all requests related to drive path generation. The particular
request type is identified by a 'purpose' variable.

The UF program with the name dpud() must identify the
purpose of the request and, accordingly, branch to the proper
service routine.

The entry point function has the following typedef:

extern int dpud ( char param, int status, int parm_len);

The string 'param' contains the data which is communicated back and
forth. To get access to this data, first cast the param to
to UF_CAM_exit_id_t, then get the DPUD specific data using the
function UF_DPUD_ask_dpud.

With this data available, the UF program can service the requests.

The following services are expected:
1. Specify user parameters
This request is made during operation editing through a
dialog button. Any parameters entered through this request
must be maintained by the UF program. To aid this maintenance,
UF_DPUD provides access to the name of the calling operation.
Available objects:
purpose
operation

2. Specify tool axis parameters
This request is also made during operation editing through a
dialog button, when USER_DEFINED tool axis is selected (this
option is only available when USER_DEFINED drive method has
been selected previously. Any parameters entered through this
request must be maintained by the UF program. To aid this
maintenance, UF_DPUD provides access to the name of the
calling operation.
Available objects:
purpose
operation

3. Specify projection vector parameters
This request is also made during operation editing through a
dialog button, when USER_DEFINED projection vector is selected
(this option is only available when the USER_DEFINED drive method
has been selected previously. Any parameters entered through
this request must be maintained by the UF program. To aid this
maintenance, UF_DPUD provides access to the name of the
calling operation.
Available objects:
purpose
operation

4. Initialize the processor
This request is made to allow the UF program to start up and
initialize internal data as required.
Available objects:
purpose
operation
tool axis option
tool axis
projection vector option
projection vector

5. Set user data size
Surface Contouring maintains several positions during processing.
Each position has an associated drive position, the structure of
which has been split into two parts, a system portion and a
user portion. These objects are allocated by the Surface
Contouring processor. While the size system portion is known to
the processor, the user portion, of course, is not known. The
set user data size service is used to provide this size.
Please specify the size in number of bytes.
For purposes of allignment, it is important that the user
data does not contain any elements greater than double, which is
currently the largest size used in the system portion.
Available objects:
purpose
operation
user data size

6. Get next drive position
This request is for the next available drive position along the
drive path. The UF program is responsible for generating
sufficiently many drive positions to satisfy any drive-path
related tolerances.
Available objects:
purpose
operation
tool axis option
tool axis
projection vector option
projection vector
drive position 0

7. Get intermediate drive position
This request is used when the direct path between two projected
drive positions does not fall within the tolerance bands of the
part geometry. The UF program must supply a drive position at
a given ratio (between 0.0 and 1.0) between the two specified
drive positions.
Available objects:
purpose
operation
tool axis option
tool axis
projection vector option
projection vector
ratio
drive position 0
drive position 1
drive position 2

8. Rewind
This request is used to reset the drive path processor back to
the beginning. In other words, after a rewind request, the next
drive position generated with be the first drive position in the
drive path.
Available objects:
purpose
operation

9. Stop the processor
When tool path generation is completed, or when the system
otherwise is interrupted (such as if a user abort is generated),
this request is generated to allow the UF program to free any
allocated internal memory and perform any other required
cleanup activities.
Available objects:
purpose
operation