This macro shows you how to create constraints on published elements.
This macro opens the CAAAsmCstOnPublish.CATProduct
document that contains two parts: a plate, Plate.CATPart, and two
instances of a screw, Screw.CATPart. It retrieves on each Product
object the Publication
objects corresponding to published elements identifying for example the
position of the holes in the plate and the axis of the screws. It creates Constraint
objects to position those elements regarding one another. It then uses the
ReplaceComponent method of the Products
collection to replace Screw.CATPart with NewScrew.CATPart, automatically
reconnecting the constraints on the published elements of the new part.
CAAAsmCstOnPublish is launched in CATIA [1]. No open document is needed.
CAAAsmCstOnPublish.CATScript is located in the CAAScdArrUseCases module. Execute macro (Windows only).
CAAAsmCstOnPublish includes the following steps:
Prolog
The macro first loads CAAAsmCstOnPublish.CATProduct that contains two Part: Plate.CATPart and Screw.CATPart for which two instances have been created: Screw.1 and Screw.2.
Those objects use the Publication capability of CATIA V5 to expose some of their elements using a stable name. The plate published as "Top" its top face and as "Hole1" and "Hole2" the center points of the two holes. The screw publishes as "HeadBottom" the bottom face of its head and as "Axis" its axis.
... ' -------------------------- ' Get the different products ' -------------------------- Dim oRootProduct As Product Set oRootProduct=CATIA.ActiveDocument.Product Dim oPlate As Product Set oPlate = CATIA.ActiveDocument.Product.Products.Item ( "Plate.1" ) Dim oScrew1 As Product Set oScrew1 = CATIA.ActiveDocument.Product.Products.Item ( "Screw.1" ) Dim oScrew2 As Product Set oScrew2 = CATIA.ActiveDocument.Product.Products.Item ( "Screw.2" ) ... |
Once the new product document has been loaded, the oPlate,
oScrew1 and oScrew2 variables are declared to
receive the instance of the plate and the two instances of the screw.
Those instances are fetched in the Products collection of the Root Product
using their names.
Other variables, oPlatePub, PlateRef, oScrewPub
and oScrewRef are declared and will be used in the following
to receive plate and screws publications and the underlying published
elements. Those published elements will be manipulated as Reference
objects.
Creating Constraints
...
' --------------------------------------
' Create offset constraint between plate
' top face and screws heads bottom faces
' --------------------------------------
set oPlatePub = oPlate.Publications.Item("Top")
Set oPlateRef = oPlatePub.Valuation
' ---> Plate/Top Screw1/HeadBottom
Set oScrewPub = oScrew1.Publications.Item("HeadBottom")
Set oScrewRef = oScrewPub.Valuation
Dim oConstraint1 As Constraint
Set oConstraint1 = oConstraints0.AddBiEltCst ( catCstTypeDistance, oPlateRef, oScrewRef )
oConstraint1.Dimension.Value = 2.000000
oConstraint1.Orientation = catCstOrientOpposite
...
|
The Publication object corresponding to the top surface of the
plate is fetched in the Publications collection of tthe oPlate
Product object using its name: "Top". A reference on the
underlying published object is then obtained using the Valuation
method of the Publication object. We proceed the same way for the
bottom face of the head of the screw.
Using those 2 references an offset constraint is created using the AddBiEltCst
method of the Constraints collection. AddBiEltSct is
used to create constraints involving two elements, valuating the first
argument to catCstTypeDistance creates a distance (or offset) constraint
between the two objects passed as second and third arguments. Constraint
types are defined in the CatConstraintType
enum.
The Dimension method is used on the resulting Constraint
object to specify the value of the distance (here 2 mm) and the Orientation
method allows to specify the orientation for the second geometric element
with regard to the first one. Constraint orientations are defined in the CatConstraintOrientation
enum.
Three other constraints are created the same way: offset between the top face of the plate and the bottom face of the second screw and coincidence between the axis of each screw and the center of the corresponding home of the plate.
... ' -------------------------------------- ' Update the Product .. ' -------------------------------------- oRootProduct.Update ... |
The Root Product is then updated to move the parts in a position respecting the contraints to newly created constraint giving the following result.
... MsgBox "Click OK to replace the screw by another standard screw ..." ... |
A message box is displayed allowing to see the intermediary result before going on. On Unix the result will only be visible at the end of the macro.
Replacing the Screw by Another Screw
...
' --------------------------------------
' Replace the screw by another one: constraints on
' published elements are autoatically reconnected ...
' --------------------------------------
Set oScrew1 = oRootProduct.Products.ReplaceComponent ( _
oScrew1, _
sDocPath & "\online\CAAScdAsmUseCases\samples\NewScrew.CATPart", _
True)
' --------------------------------------
' Update the Product with the new Parts
' --------------------------------------
oRootProduct.Update
...
|
The ReplaceComponent method of the Products
collection of the Root Product allows to replace all instances of the
reference product of oScrew1 (Screw.CATPart) by instances of
a new reference product whose full Path is passed as second argument (here
NewScrew.CATPart).
All constraints on published elements are automatically reconnected and updating the Root Product automatically positions the new instances in the assembly:
