I had a quick look at your parts, and they are very good ;) The thing that bothers me (related with internal surfaces) is "bleeding ", surfaces that end in the middle of other surfaces (tube ends in the middle of part sides). This is visible even with opaque parts.
Otherwise, my rule of thumb for primitive usage:
- whenever possible, use special primitives for studs, anti studs, bars, clips etc. Not only they simplify part design, they also often provide connectivity automatically, or at least will help defining it.
- it is generally valuable to use primitives for all round elements (cones, cylinders, discs and rings). They improve part look, especially when seen with primitive substitution with high number of segments (using ldview). Getting a good look with substitution can be very tricky though, bad designs can result in gaps or overhangs!
- I use other primitives such as boxes or triangular prisms only when they simplify design. Benefit of using them is pretty low otherwise... Used to be good to reduce file size, but in this era of multi GB hard disk this becomes a moot point !
Otherwise, my rule of thumb for primitive usage:
- whenever possible, use special primitives for studs, anti studs, bars, clips etc. Not only they simplify part design, they also often provide connectivity automatically, or at least will help defining it.
- it is generally valuable to use primitives for all round elements (cones, cylinders, discs and rings). They improve part look, especially when seen with primitive substitution with high number of segments (using ldview). Getting a good look with substitution can be very tricky though, bad designs can result in gaps or overhangs!
- I use other primitives such as boxes or triangular prisms only when they simplify design. Benefit of using them is pretty low otherwise... Used to be good to reduce file size, but in this era of multi GB hard disk this becomes a moot point !