Choose the question before choosing the process
For a prototype, decide what you want to learn. For a working part, describe the load, environment and mating features. For a repeat quantity, keep the revision and specification clear. These three starting points help give the enquiry enough context to be useful.
FDM or resin?
FDM builds forms from deposited filament. Resin printing uses a light-sensitive material. Surface detail, geometry, orientation and material formulation all affect the choice. Neither process name is a promise of a particular tolerance or strength.
The materials guide separates general education from confirmed options. For larger parts, discuss the overall dimensions before assuming a printable envelope. If you need a model created or changed, CAD help is a separate scoped route.