1) this was official forum
2) look on features in ViaCAD Pro they say something about ACIS in ViaCAD 2d/3d is nothing. Look also that ViaCad 2d/3d has no STEP translator which has been done with using ACIS.

Edit: For that price of ViaCAD Pro is possible to buy parametric Alibre Design (also ACIS).

Edit2: Is it very expensive to include ACIS kernel from MoI modeling tools into even if MoI would cost twice? Is it possible? I mean only those which are better. Or its bad idea to mix more than one kernel in CAD software? I deam loudly about MoI with some ACIS/parasolid filleting, offseting and shelling. I`m asking because in Rhino I use very nice Xnurbs patching plugin which has own kernel only for this single operation and it`s brilliant. I hope there will be more plugins like that.