Kerbal Space Program is a fun little indie game (currently in early alpha stages of development)
I started playing the game a while back in 2011, approximately 10 days after it was first released to the public.
I found myself spending a lot of time playing the game and especially enjoying the hilarious little Kerbals who would scream or smile with joy during the flights of the rockets you design within the game. Three of these little 'Kerbal' characters got famous within the community pretty fast, they are known as Bill, Bob and of course Jeb (the crazy dare-devil Kerbal rocket pilot)
So after a few days playing KSP, I decided to start an interesting fan-art project...
I wanted to make some 3D printed Kerbal figurines
This was no easy task, Id decided to make the Kerbal character, along with a helmet (which could be put on the character, or taken off) plus a transparent visor which could also be added or removed from the helmet. So this would require 2 different materials, making the design even more of a challenge.
Programs needed for the task at hand:
- 3D modelling program of choice (I used Blender)
- 2D program of choice ie Photoshop (I used GIMP in this case)
- netfab studio and/or
The 3D printing will be done via Shapeways (http://www.shapeways.com/)
(note that as of posting this, I only have 2 of 3 Kerbals printed out, the 3rd and final Kerbal will be printed sometime next month to complete the set, hopefully!)
This also my first instructable, so I hope people like it, make sure to leave a comment and feedback!
Either way, lets get into it:
Step 1: Planning, References, Sizing, Material Choice+Research
First up, its always good to do a bit of planning.
I went directly to the kerbal space program site for reference pictures (theres a very limited amount of pictures of the actual kerbals around, maybe 2-3 pictures in total on the site) The little Kerbal sitting on the preorder/donate button and the 3 in the banner up the top were pretty much all I had to work with, but it was enough.
The next thing I needed to think about was the size of the model, relative to how much I wanted to spend for this project. To work that out, I needed to have information about the material(s) to print the final model in.
(Page with details for all the materials at shapeways - http://www.shapeways.com/materials)
Since I didnt want to paint the models once they were printed (or any additional post-production work for that matter) I decided that the 'Full Colour Sandstone' was a good option. Its an easy choice to make, since theres no other material at this stage which prints full colour models.
For the visor things are a bit trickier, and it took a few test prints before I found the right material. I wanted something transparent (preferably plastic) so the visor is see-though enough to see the Kerbals face behind it.
I ended up choosing the 'Transparent Detail' material, its not perfect, but its the best material Shapeways had to offer for this.
Full Colour Sandstone (FCS) material page for more info - http://www.shapeways.com/materials/fullcolor
Transparent Detail (TD) material page for more info - http://www.shapeways.com/materials/white_detail
So now with the details of the material(s) known, I worked on determining how big to make the model, without having to sell off limbs and cars/houses to fund the project (3D printing *can* be very expensive, if your not careful)
Note - another important thing these material details provide us with, is the 'detail tolerance' of the material. This is important, because it lets us know what level of detail the material can be printed in - ie theres no point modeling in details down to 1mm, if the material only had details down to 4mm printable, this additional detail wont turn up in the final print and will be a waste of time and effort.
Its also important to know if the model will print correctly, ie if you have a tiny tube or wire, or thin part of the character mesh, it might print so thin that the material breaks during transport, or deforms in a way you dont want as its being printed.
To make things even more complicated, it could be worth looking into printing a 'hollow' model, to save on materials and bring the price down, but this is something I didnt do for this particular project, as the models were small enough already, and making them hollow would be troublesome and in the end not worth the effort.
So with all of this in mind, I determined that the models should aim to stand at around 3 inches tall (while wearing the helmet), this would allow for the level of detail needed, and not be too expensive.
Step 2: Modelling the (Kerbal) Character
The next step is to model the Kerbal character, I used Blender (an opensource program you can download for free directly from www.blender.org) but any 3D modelling program should do (as long as it can export the finished model to a useable format for 3D printing and supports UV texturing - I'll get to that soon)
I'm not going to go into much detail here about the actual process, 3D modelling is something which can take a long time to learn and theres plenty of tutorials and learning resources out there on the internet which will cover the topics better than I can here.
The modelling took several days to complete and tweak until I was happy with the result and was confident the model was weighted properly, so it would stand up without falling over.
I paid particular attention to the area where the Helmet would 'join' onto the Kerbal character. This part was tricky to get right and took some testing and iterating of the design. I needed the hole in the helmet to line up with the disc, without the disc attachment area being too large that it looked stupid, and without the hole of the helmet being too small that it wouldnt fit over the kerbals head.
(see the 'pegs' picture, with arrows indicating the particular places designed to hold the helmet)
It was also important to model 3 different expressions (for Bill, Jeb and Bob) as I wanted 3 unique Kerbal models.
I finished by adding some basic colouring to the model, which is to be later used for the final texturing stage.
Step 3: Modelling the Helmet
With the character done I moved onto the helmet, using the same techniques to model the object and all the detail associated with it. The main idea here was to model the opening for the helmet so it was wide enough to fit over the Kerbals head, and small enough to sit neatly onto the pegs of the Kerbals suit/neck disc. (See the pictures with the disc highlighted in red)
Luckily the helmet is vastly out of proportion with the Kerbal character, so all of this worked out ok with a bit of tweaking here and there.
The other requirement is to have the visor slot into the helmet, so I included some holes into the helmet, which is where the visor would plug in and be held in place.
Step 4: Modelling the Visor
The visor was probably the easiest component of the whole project to model.
To make it fit the helmet I simply duplicated the entire inside 'lip' of the helmet, including the holes, and extruded the rest of the visor from that.
This meant the visor was a perfect fit for the helmet, with the usual tweaks here and there.
I should also note that I experimented with several different materials and thicknesses for the visor.
The first visor was printed in Frosted Detail but ended up not being very foggy, and no where near as transparent enough as I needed. Another test print was super thin in the Transparent Detail material I ended up using, but was printed deformed because the walls were so thin. It can take several attempts to get a object right when printing out materials your not familiar with, or objects that are very small - in this case both.
Step 5: Texturing
With the model done it was time to look at texturing so the Kerbal and Helmet would be 3D printed in full colour. The visor, since it was to be printed in Transparent Detail, has no texture so it jumped straight to being exported for printing (the next step).
To texture the models I needed to first 'UV unwrap' both of the objects. Once that was done I could bake two texture maps out of Blender to be combined together in my 2D program of choice.
The two texture maps baked (an Ambient Occlusion pass, and a colour pass) were combined and tweaked to make the final diffuse map.
The max texture size for printing in colour sandstone is 2048x2048 so this is the size I set the textures to for the highest quality.
The model at this stage is *almost* ready to be exported, and sent off to print!
Step 6: Prepairing for Print/Exporting
Before exporting the model(s) I added an armature, this was to allow me to easily and efficiently adapt the base mesh into whatever pose I needed, to add further differences between the Bill, Bob and Jeb models.
Once this is done its time to export.
I chose to use the .x3d format (one of the suggested ones on the Shapeways uploader for coloured model exporting). This format preserves UV's and textures, which is exactly what I needed.
From here I could send the model straight to Shapeways to be printed, but it would probably fail during the automated checking. Theres one thing left to adjust - the size of the model.
This is something Blender isnt the best for, so I downloaded Netfabb and imported the model. This can also be done using MeshLab.
Shapeways has a good tutorial for using both of these programs to prepare a 3D print here - http://www.shapeways.com/tutorials/how_to_use_meshlab_and_netfabb
Once the model is imported into netfabb the dimensions get set to a real world scale, in this case I'm choosing to work in 'mm'. Netfabb also has some useful tools for analyzing a model and will tell you the exact volume of material the model will use when its printed. This is very handy when your dealing with the prices of 3D printing materials (per cm^3), since you can use these numbers to determine the price of the model before its even uploaded to Shapeways. Netfabb also has tools for fixing meshes, displaying any inverted normals and other problems which may arise.
The model was then re-sized using Netfabb, and finally exported to a similar format (.x3db). The final step before uploading is to put the .x3db mesh in a .zip along with the texture (either a .jpg or .png). Then its off to shapeways to upload and order!
~2 weeks later the prints have been produced, shipped and arrive (shipping takes a while to get to us Aussies)
So, thats the process!
Feedback, questions and comments would be great to hear :)
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