3D Model a Robot From Reference Images Using TinkerCAD

This project came about as a request from a father looking to find a specific toy for his son. They were looking for the Music Robot from Outer Space which was a character in an episode of the show "Little Einstein's". There seemed to be no models on the internet to use so we decided to design from scratch. We noticed that the robot was mostly made of traditional geometric shapes like rectangles, spheres and cylinders. This gave us confidence that we can model this object accurately using TinkerCAD.com. This Instructable is meant to show the decisions that get made when trying to 3D model an object from a reference image and prepare it for 3D printing. You will notice that all the steps and decisions are interconnected to each other. If you would like to download the finished model you can find it at this link here on cults.com

Reference images - Music Robot from Outer Space

3D Modeling Software - TinkerCAD

Slicing Program - Prusa Slicer

PLA Filament - Overature PLA 1.75mm

The goal for the next 4 steps is to break down this complex object into parts (arms, legs, head, body). Then we want to break down those parts into their major geometric shapes. Finally we will add the details to get the most realistic look. The arms consist of a cylinder shape in black which is simple. The shoulders in blue are a combination of a "box" and "round roof" which are already available in TinkerCAD to use. For the red claw we took advantage of the new "sketch tool" to draw the shape we wanted from the side. There are usually multiple options to create the shape you want. Once you are happy with the look you can group those objects together. A quick copy and paste will give you two arms.

The legs and shoes are up next. We used a series of spheres that were squished down to make the actual legs in blue. The shoes are made of standard rectangle with a twist. TinkerCAD lets you adjust settings for many of its shapes. We increased the radius and steps of the edges to get a more rounded look for the red and white areas. The white part was cut flat on bottom using a box set to "hole" and grouping them together. This makes for a good starting surface to print on. The yellow wheels with the black dots were made using cylinder shapes turned on their side.

The head has a few more details to work on than the last two parts. There are 3 cylinders making up most of the head with a half sphere shape on top. The eyes are made of 2 sets of spheres sunken into each other. The mouth is another cylinder flatten out to a disk shape. Finally the antennas consist of a sphere, a cylinder and a half sphere. These tiny poles will almost certainly be the first part to break on this toy. It might have been wise to have them placed up against the head so they are attached with no air gap.

The main body has the most details and has more than 5 colors adding to the difficulty. We designed the batteries to be printed separately so we can use pink green yellow, white as additional colors beyond the black, grey, blue, red, yellow. Spaces were left to Glue in these batteries and buttons afterwards. The grey body is much more simple now basically made of 3 cube shapes. We messed around with some pyramid shapes for the emblem in the middle of the chest. The batteries themselves consist of cylinder shapes and then we used a fancy tricky to convert images into 3D objects for the lighting. You can learn that technique in our other instructable found here. Keep in mind if the buttons are 3 mm and the holes you leave are 3mm, they probably wont fit. You will need to leave a bit of gap or tolerance. Something like 0.3 mm difference has worked for us.

The decision to print this object in 1 single color vs multiple colors will depend on the technology you have access to. Single color printers are cheaper, easier to use and more common for beginner hobbyist. There is no need for the filament in the printer to switch colors which causes waste of material and time. The time and cost to print this robot 6 inches tall in single color is roughly 8 hours and $2.50. Compare that to fully multi color which can be as much as 28 hours and $8.00. Clearly an all grey robot is not as interesting as a fully colored one but if you have access to a talented artist, air brushing or painting the colors on after is an option. The correct choice for you may depend on if you are making 1 masterpiece or trying to mass produce your object quickly and efficiently. The 3D printer we use is a Prusa MK3s With a MMU3 upgrade. This machine is limited to 5 colors but with some tricks you can possibly get more into the design. Looking at the reference there are mainly 5 colors to work with if you ignore the batteries and buttons. We found a work around for this issue in the next step.

The decision to make this robot toy as one solid object or multiple pieces that assemble together is closely related to the choice of single color vs multicolor in the previous step. The time and effort to design pieces that fit together correctly is much more than designing one solid object. That being said, toys that move are often much more engaging. Having the arms and head rotate could be a nice addition but would take some time to get the tolerance and fit correct. There is the issue of there being over 5 colors in this model so we ended up taking a hybrid approach. The main body was printed in one piece using red, yellow, blue, black and grey. We decided to print the batteries and buttons separately and glue them in place later. We left cut out holes in their place so these piece fit snug. The design now has more than 5 colors but did not take much more design time.

Now that the model has been created it is time to bring it into a 3D printing slicer. This will set up all the information the 3D printer needed to actual make this model. there are 100's of setting that can be tinkered with but we are focusing on the print orientation and supports in this step. Most 3D printers create objects in layers stacked on top of each other vertically. Choosing which way the model is oriented on the print bed will have drastic changes on the time and cost. Printing this object vertically in full multicolor is 28 hours and $8 as mentioned before. Lying this object on its back would change the numbers to 24 hours and $6 in cost. Another benefit is the legs and arms would be less likely to break as the layers are running parallel instead of perpendicular to the lengths. The downside is there would be tons of contact points between the supports and the back of the object which usually leaves some ugliness when removed. We felt the upright orientation was best since the robot mostly supports itself. The hands and hips were the main areas that would be supported in this case.

If the printing fairies treat you well... you will have a finished prototype designed start to finish. All that is left is to glue the batteries and buttons in place. Take a look at your work and be confident you can apply these techniques to any object. You will find many tasks will become easier by breaking them down into smaller, more manageable pieces. We were very happy to get this project completed in a very short amount of time in order to keep cost down for our customer. They were thrilled with the final product.