V-REP allows calculating and adding the convex hull of specified objects. The convex hull of a collection of meshes is the smallest convex envelope that encompasses all meshes. V-REP allows extracting the convex hull of measurable objects only. The calculated convex hull might not be "water-tight" (i.e. might contain overlapping triangles or non-shared edges), thus the shape will not be marked as convex. You can however run a convex decomposition function on the generated shape.
To add a convex hull, select objects that you want to have included in the convex hull and select [Menu bar --> Add --> Convex hull of selection]
Depending on situations, convex hulls can drastically reduce calculation times in case of distance calculations or proximity sensor simulations for instance. Collision detection can also be performed faster if a rougher approximation (i.e. the convex hull) of a complex shape is used instead. One can also extract the convex hull of a model (e.g. robot), then make it invisible, but perform all calculations (collision detection, distance calculations, etc.) using the invisible convex hull instead of the complex model.
[Objects forming a robot model (left) and corresponding simplified representation as convex hull (right)]