McQuarrie Technical Drawing - Digital Twin
McQuarrie Technical Drawing - Summary
Following a series of concept sketches and concept drawings, this appears to be the the earliest purely technical R2-D2 drawing.
McQuarrie Technical Drawing - Provenance
It's not necessarily intuitive that, in addition to concept art, Ralph McQuarrie is also recognized as an experienced technical draftsman. Star Wars Costumes by Brandon Alinger documents the early technical drawing as credited to McQuarrie.
McQuarrie Technical Drawing - Head Profile
The technical drawing shows the head as being a slight modified hemisphere. The head profiles is elongated with a ring at the bottom of the hemisphere.
McQuarrie Technical Drawing - Diameter
The most basic dimension setting up all the proportions on the drawing is the diameters of the head and body. This early in the production the diameter is called out as 18 inches.
McQuarrie Technical Drawing - Wheels
The drawing includes the packaging of crescent shaped wheel clearance features in the foot. This design appear to be meant to have both wheels and Kenny's feet coexisting inside the foot shell. Although the direction to have the wheel and the motor coexist was dropped, the crescent feature was retained through to production.
McQuarrie Technical Drawing - Antenna
One of the interesting ideas on this drawing include the original concept of a removal screw-in antennae on the top of the dome. The threaded receptacle for this antennae made it through all of the production drawings but was never physically built.
McQuarrie Technical Drawing - Shoulder Bearing
This drawing has the smaller shoulder bearing that persisted in the design all the way through to the last minute horseshoe mod.
McQuarrie Technical Drawing - Rear Throw
The two leg to three leg transition throws the center foot to the rear of the robot. This was later changed to throw to the front of the robot in the final film.
McQuarrie Technical Drawing - Fairings
The design includes rigid fairings between the traction drive foot assembly and the body that are assumed to have the ability to retract. These can be seen as having been fabricated as joined to the lower ring assembly in some of the photos taken at EMI but never made it on film.
McQuarrie Technical Drawing - Horseshoe
This design has inboard facing shoulder horseshoes and the outboard facing legs and ankles. This earlier design not require any of the clearance cutouts in the body that were a necessary last minute after the "horseshoe mod." This was likely the final significant last minute design change before filming.
McQuarrie Technical Drawing - Motor Enclosures
A final observation about this design is the Motor Enclosures attachment to the legs instead of the foot. This requires that the Motor Enclosures have a chamfered relief in order to be able to rotate with the leg during the 2 leg to 3 leg transition. The rotating Motor Enclosure can be seen in the right most view of the drawing which shows the unit in its 3 leg configuration.