No supports needed. I used 3 perimeters to ensure the hinges are strong, this is much preferred over trying to obtain strength through infill. If you use too high infill, the model may become poorly balanced due to the head being too heavy. If you want to improve stability, use a higher infill for the piece with the legs if you can.rnrnThis should move freely right after you take it off the build plate. If you print with hairspray on a glass bed, the Rex should spontaneously jump into a random pose all by itself when it pops off the plate after cooling down. If you need to use force to free the hinges, you still have some optimization work to do on your printing technique.rnrnThis is not a demanding print. If this is one of the first things you're printing and it fails, expect other things to fail as well.
Hinge Design If you want to create your own flexible model, by all means copy the hinge design from this one, or at least use the below image as a guideline. I see way too many u2018flexiu2019 models that still use the weak hinge design from the original model, or other shapes that have way too little material in the most crucial locations, often the end of the shackle or u2018ringu2019 is too thin. Make sure to provide as much material around the axle hole as possible, instead of cutting away as much as possible, as some designers tend to do. You won't gain any flexibility by providing more clearance than needed, the model will only become weaker. This thing was created by Thingiverse user DrLex