STL CAD Design Needed

I have a concept that now needs to leave the sketchbook and become a precise digital model. All I require at this stage is an accurate CAD file delivered in STL format, ready for downstream use. The physical... (Budget: ₹750 - ₹1250 INR, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Print Design, CAD / SolidWorks, CAD/CAM, Product Design, Solidworks)