0028747: Incorrect result of the section operation after edge refinement

Implementation of the method for simplification of the result of Boolean Operation on the API level.
The method BRepAlgoAPI_BuilderAlgo::SimplifyResult has been added, so the derived classes such as BooleanOpeation and Splitter can also use this method.
The result shape simplification should be called after the operation is done. The simplification is performed by the means of ShapeUpgrade_UnifySameDomain algorithm.

Draw command "bsimplify" has been added to control the simplification options.
Documentation for new functionality and draw commands controlling the options of Boolean operations.
Test cases for the new functionality.

Side-effect change:
The algorithms in Boolean component have been changed to use the BRepTools_History as a History tool.
Now it became possible to disable the collection of shapes modifications during Boolean Operations, which may be useful for performance sake (in draw the option is controlled by *setfillhistory* command).
Draw command "unifysamedom" has been changed to accept the angular tolerance in degrees instead of radians.

dox/user_guides/boolean_operations/boolean_operations.md

@@ -3070,6 +3070,50 @@ generated gf2 com_hist f2
 
 ~~~~
 
+@section occt_algorithms_simplification BOP result simplification
+
+The API algorithms implementing Boolean Operations provide possibility to simplify the result shape by unification of the connected tangential edges and faces.
+This simplification is performed by the method *SimplifyResult* which is implemented in the class *BRepAlgoAPI_BuilderAlgo* (General Fuse operation).
+It makes it available for users of the classes *BRepAlgoAPI_BooleanOperation* (all Boolean Operations) and *BRepAlgoAPI_Splitter* (split operation).
+
+The simplification is performed by the means of *ShapeUpgrade_UnifySameDom* algorithm. The result of operation is overwritten with the simplified result.
+
+The simplification is performed without creation of the Internal shapes, i.e. shapes connections will never be broken. It is performed on the whole result shape.
+Thus, if the input shapes contained connected tangent edges or faces unmodified during the operation they will also be unified.
+
+History of the simplification is merged into the main history of operation, thus it will be accounted when asking for Modified, Generated and Deleted shapes.
+
+Some options of the main operation are passed into the Unifier:
+- Fuzzy tolerance of the operation is given to the Unifier as the linear tolerance.
+- Non destructive mode here controls the safe input mode in Unifier.
+
+For controlling this possibility in DRAW the command **bsimplify** has been implemented. Please see the @ref occt_draw_bop_options "Boolean Operations options" chapter in draw user guide.
+
+
+@subsection occt_algorithms_simplification_examples Examples
+
+Here is the simple example of simplification of the result of Fuse operation of two boxes:
+
+~~~~
+bsimplify -f 1
+
+box b1 10 10 15
+box b2 3 7 0 10 10 15
+bclearobjects
+bcleartools
+baddobjects b1
+baddtools b2
+bfillds
+bapibop r 1
+~~~~
+
+<table align="center">
+  <tr>
+    <td>@figure{/user_guides/boolean_operations/images/bop_simple_001.png, "Not simplified result", 420}</td>
+    <td>@figure{/user_guides/boolean_operations/images/bop_simple_002.png, "Simplified result", 420}</td>
+  </tr>
+</table>
+
 
 @section occt_algorithms_11b Usage