modeling of complex forms

[deep70]

Hello to all boys,
I would like to ask you if there is an application for the realization of models with complex holes, I have to decide whether to take into charge the modeling of cast iron pump bodies starting from a dwg.
they did not ask me for the creation of the mold, but the model, probably the mold will do it with some different software I imagine.
Thank you all for any given answers, good day and good work to all.
(example)

 

[MassiVonWeizen]

I don't know if there is a dedicated application for this type of modeling, I don't even know how to do some research.
without application is a large sweep of lofts and surfaces and import all possible views of the dwg so as to keep an eye on geometry.
I imagine that being a piece made merges in certain areas is acceptable a margin of error

 

[deep70]

I'm actually evaluating it, I'll try to see how it goes with the first.. also because they use a modeling system to themselves.. thanks many for the massive answer, very kind as always.