Unification is the process where two touching or connected forms of like materials (parts) are virtually stitched together to present one monolithic representation. In AECOsim Building Designer, a new Dynamic View Unification algorithm is available called “Unification Glue”. This algorithm provides superlative dynamic view unification performance (4 times greater) and enables greater tolerance between touching and connected geometry. Unification Glue is also a multi-thread utility that can support 32 bit and 64 bit processing. It will be most efficient if 8Gb or more of RAM is available.

Unification Glue is enabled and controlled by the configuration variable BB_UNIFICATION_METHOD which allows you to choose from two different Unification algorithms. The default "GLUE" is the newer and superior method, particularly for DVs.

The "MERGE" value is also available. This will use the legacy unification code, where elements that completely intersect each other will still unify. Use of this option is not recommended as it allows inaccurate modelling to be overlooked or hidden. Intersecting or overlapping elements are not representative of the real-world design intent and contrary to best practice BIM processes. They can also result in false positives during clash detection and inaccurate material quantities.

Unification Glue is enabled and set to BB_UNIFICATION_METHOD=GLUE by default.

Unification Glue will perform "only" under the following scenarios:

• Unification Glue does not unify crossing or embedded geometry. Two forms must fall within the unification tolerance (see below) in order for the overlap or gap between them to be unified.
• Unification Glue is applied only to Dynamic Views and is not employed by the Drawing Extraction Manager for drawing extractions.

- Here is a simple example where Unification Glue will not unify these two elements, even though they have the same part assigned, because they are not touching, but instead are completely intersecting each other:

- Another example, notice that the elements are coincident and In this case the “Unification Glue” does perform the unification correctly.  Both elements share the same part:

Unification Tolerance

The unification tolerance is set by the configuration variable BB_UNIFICATION_TOLERANCE_MM. The default value of this tolerance is 7mm. We have found this to be the optimal value during design and testing of this feature.

[Note 14 Apr 2106: ABD help currently lists the name of this variable as BB_UNIFICATION_TOLERANCE, this has been noted and will be corrected in a later release.]

If elements are of are of the same type or have the same unifier assigned in Families and Parts, they will be displayed as unified assemblies, for instance concrete edge beams and slabs, if they touch or are less than 7mm apart. The example below demonstrates this. the two walls on the left are touching, those to the right have small gaps between them, the two on the right overlap:

With the default tolerance of 7mm they unify as shown, the four walls to the left that are touching, 5mm and 7mm apart are unified the others are not. The overlapping walls are not unified indicating that the model should be corrected to reflect real-world construction:

Note that the tolerance of 7mm also applies to overlaps, elements can overlap by less than 7mm and still be unified, If clash detection is in use overlaps should be avoided wherever possible, although these can be managed by appropriate use of tolerances in the clash process.

Setting the tolerance to 25mm includes the two walls with 15 and 25mm in the unification. This is not recommended, we just include this as a demonstration of the effect: