We've been buying the products of a supplier of window and door hardware (locking systems etc.) for around 10 years. We spend tens of thousands of GBP with them per year.
They're changing some of their product lines to update them and make their locks more secure etc. and they are discontinuing their old products.
The new products are NOT a direct replacement for the old - some sizes, fixing details etc. change which means we have to change the design of our products to suit.
In doing so, I have asked for some 3D cad files. We model everything already in 3D CAD and so it is relatively easy if we have our suppliers' CAD models to put the right bits in the right places, work out any tolerances, positioning, clashes of components etc.
Our supplier has come back and said that they have a policy of not sharing their 3D CAD files, presumably to prevent reverse-engineering of their products. They'll send 2D CAD files in some instances but not for everything. They do already have 3D CAD models of their components - it's very clear and obvious from their sales and technical literature as there are views of the components from different angles etc. which could only be produced from a 3D CAD model, so it's not as if they'd have to create the files specially for me. The components in question are not particularly complicated in terms of component/assembly design. Holding one in my hand I could learn everything I need to know about how they are made, what they are made of etc. if I were to want to get some of my own made.
There is nothing I could learn from having a 3D CAD model that I could not learn from having the physical item, BUT I could really use the CAD model to make my work significantly easier. As it is, I will have to create a 3D model myself which will be a pain and take time I could be using more productively. Other similar suppliers have given us 3D CAD when asked.
My question is: are there any benefits to this hardware supplier of not giving me the CAD model which I haven't thought of? Also is there some way I can convince them to hand over the goods? I could look for another supplier but this would be a huge pain at this point because of how integrated into our designs this particular supplier's products are. From my point of view this gives them no actual benefits, and only serves to annoy their customers.