Introduction: Mr. Pumpkinhead : Make Your Own Adorable Figure With 3D Printer

A few years ago, I made a short computer animation with my friends for a class project. The animaiton was called "Garageband", which is composed of three band members playing musical instruments. As our theme was kinda monstrous band, we created a halloween pumplkinhead guitarist, a monster drummer, and a skeleton purcussionist. The pumpkinhead was my design.

Recently, I found my school purchased a 3D printer for industrial design students and it is also available for other students. I was so fascinated by this magical gadget and eventually decided to try it out - print my own character model.

I would like to share my first 3D printing experience with you.

Here, you can see the animation that my team made in 2008 and revised in 2011. We created each character animation via fullbody motion capture system with our own performance.

Step 1: Tools and Material

Well, there are not many stuff necessary to do this hobby work since most important part is modeling and printing itself.
Then, some painting material and a few of misc items to finish the project. Here is a list of materials used.

HW & SW
- Autodesk Maya and STL plugin for modeling and exporting model to 3D printer friendly STL format
- Dimension uPrint plus 3D printer: prototyping 3D printer using abs plastic material.

Material used
- Sand paper (600 & 1000 Grit to sand printed model's surface)
- Plastic Modeling Putty (fill rough gaps on layered printing surface)
- Epoxy Modeling Putty (glue parts. i.e. head & body)
- Acrylic paints for plastic model
- Leather Strip (make guitar strap. from local art supply)
- 28 AWG steel wire (guitar strings)
- Ear-loop Mask (quick and easy cloak build)
- CR 2032 battery & holder (power LED light)
- Mini slide switch
- White bright LED

Step 2: Modeling

Since the original guitarist model was designed for animation, there are some parts need to be changed.
For instance, single faced mesh visible from outside does not have inner volume to form a mass in 3D printing.
Therefore, I had to re-design or change its original mesh model, especially a head piece.

Also some parts of arm and leg were slightly changed such as more round ball shape knee and elbow. This is a bit of trick to hide somewhat annoying folding of mesh in cylinder shape near joint area.

From the T-posed model, I scrubbed through entire animation track to pick a interesting and dynamic pose for my model as we can see in the second picture. Then, modified mesh as explained.

After re-modeling mesh, I laid down all parts within 8"x8" plane to see if all components are fit to printing volume. In fact, some parts, head and body, were splitted for later process (i.e. painting and LED lighting circuit).

In fact, I might just print it as it is however, I was not sure what could happen with such thin arms and legs during washing process. It could be broken inside water jet bath. So, I decided split all parts. It can also reduce supporting material usage that saves printing cost.

The height of the original model was about same as me, 6 feet. I scaled it down to 1/10 to make it around 8 inches tall.

Step 3: 3D Printing

Printer
3D printer I used is uPrint plus system from Dimension (see manufacturer's webpage). Its max printing size (size of base pallette and height) is 8" x 8" x 6". The printer looks like small size cabinet with glass window at a glance.

Once my model is ready to print out (file saved in STL format from Maya), then use printing software to nicely layout each model parts and pre-process model data for the printer, so-called packing.
During this step, we can decide its printing quality and material density. Since I liked to have decent weight of my model, I chose solid printing in highest quality setting.

Printing
Alright, ready to roll. Once printing job is queued, just need to push start button on printer's control panel.
Below video clips shows 18 hours printing process as timelapse video. It was clearly overnight process.


18 hours... after all. I got this printed model on palettee. As the printing process itself is layering melted ABS plastic on palettee, all the void area below model surface were filled with supporting material in honeycomb structure.

Washing
Then, it went through washing process which basically desolves unnecessary supporting material from model. In case of a small part, we can use steel cage not to lose parts in that deep tank with full of soap liquid.
After a few hours washing process, all model came out clean and nice. All parts pulled out of tank and rinsed with clean running water.

Hooray! Here all parts came out. Let them dry.


Step 4: Apply Primer

Printed model parts themselves are pretty cute with ivory abs plastic color however, I wanted to make it closer to the original design instead of garage kit type figure.

All parts were sanded with Grit 600 & 1000 sanding paper. Then, applied plastic putty to fill rough holes and thick traces of printing layers. Sand the surface again. Repeat putty and sanding until all surfaces get clean and smooth. Lastly used white primer for better painting.

Two body parts (back and front) were glued. For pumpkin head pieces, I painted inside with yellow first and then glued.
Plastic putty also helps to fill the visible seam on glued part (head and body). Apply putty around seam and sand it again. It will be invisible after painting.

Here are cleaned parts with putty and primer applied.

Step 5: Assemble Hand and Head

To glue hand and arm, foot and leg, epoxy putty was used.
This is because there is a bit of gap between parts, which makes common plastic glue not work that well.
Epoxy putty fills gaps well and it dries out quite strong in a day. It works as almost same as good cement or glue in this case.

Epoxy putty is consist of two separate types of material, resin and hardener. (see dark and white in the picture). Mix them well together, then put a small amount into a hole and stick the part firmly.

Since I did not make all details of my model before printing, some parts need specical care.
Especially, attaching a head on body part was post modeling. There were only holes in each parts considering light LED wiring.

Either I had to glue it or make something to tie together. I found something useful in my toolbox, a plastic pipette.
Cut a top part of it and insert it into a hole in body part. Bingo, perfect fit. Glued and cut off top part to make a hole through for later wiring.

The size of pipette was a bit smaller than a hole in head part. So, added some epoxy putty around to make it tighter.

Step 6: Painting

Painting is a whole lot fun process. Needed lots of thinking, planning, trial and error fix.
There are many different types of paints for hobby project however, my choice was acrylic paints. It is because acrylic paint is hazadous fume, odor free and water based. Good for home use without concerning too much of health issue nor sophisticated tools required in other paint types.


Hands and Arms
Initially, I planned to sand out all printing layers and make my model smooth. However, I realized that it would be cool to leave it as is. Something like carved wood feel to it. For hand, applied black base color first and slightly washed it using a cotton swab so that it does not affect too much on later top color. It's for recess over bright color in the final finish.
Multiple layers of white painting blends well with base black to create smooth natural shade around hand model.
Arm is painted with dark brown like some sort of a tree branch. I used similar color scheme for legs and feet.

Head and Body
Pumpkinhead is the most important part in the whole model. I started with base color, mid-tone orange. Then, created multiple layers of shadow and highlight with various orange tone. Inner part of head is painted with yellowish color before glued them together.
Body is greenish base coat with some dry brushing with brighter greens. 

Here all pieces painted.

Step 7: LED Light Insertion

One thing for sure when I re-modeled body is to prepare for LED lighting circuit insertion. They should be inside the body.
So, I made more room and opening. Made a rectangular hole for switch (in fact, I was not sure which switch I gonna use, so did not make a switch hole in the model at first).

I need a LED light inside of a pumpkinhead. It completes the concept of halloween pumpkinhead. The simplest solution is to use a small bright LED. With coin cell battery, making LED throwie style gadget is easy enough (see the second picture of LED throwie diagram) Found a good battery holder and small switch from local radioshack store.

Glued a small slide switch on the switch panel and soldered wires to a CR2032 battery holder.
Another pair of wires attached for LED connection.

To insert LED inside neck tube made out of plastic pipette, used black sponge I found in my circuit toolbox that came with a little IC components. Cut it round to fit inside the tube and inserted LED leads through it.

As LED assembly is ready, get all pieces inside body. Two wires goes through neck tube to connect LED.

Then, cover its back opening with a switch panel.

Connect LED (sure soldered it) and insert it into neck.

Since this LED is bright white color, I added some orange paint around to help lighting color match to a candle light.

Step 8: Make Cloak

Well, a cloak is supposed to be something like fabric.
The original design was using a kind of fall leaves around it but I thought that it may look strange with pastel tone acrylic colored body. Sure enough I wanted something simple to build. So, I looked around my closet and storage boxes I usually put all misc. stuff at home. Whala, there was one that might work, Earloop Mask. I purchased it when we had life threatening flu years ago (used for international trip :) ).

It has some wrinkles, folds and fabric like texture.

Had cut unnecessary cotton earloop string.

Inserted steel wire around edge to help easy shaping.

Trimmed bottom edge in zigzag. Looks Cool. :)

Step 9: Make Guitar

Final piece of model is a guitar. Well, even though 3D printer has great precision and resolution, a guitar has too much of details such as strings and fixtures. Therefore, I simplified its model quite a bit and did some post-modeling to create details back.

Firstly, made a guitar strap out of a leather string I found in local art supplies.

Many details of modeling parts were not photographed here but pictures show its completed model.

Made two holes using pin-vise to add strap screws. A few more holes for wire fixture. Those wire fixture is made out of a wooden toothpick. :)

Thin steel wire (AWG 28) is used for guitar strings.

Here is the final model assembled and painted!

After painting job done, protective acrylic varnish was applied a few times.

Step 10: Completed

Here, it comes to the end.

Of no doubt, it was a quite fun project. The final figure is slightly different from the original design in shape and color scheme however, I believe that it's well done considering that this is the first time I made it using 3D printer.
I would like to make some more models later using 3D printer again.

Here are some photos of Mr. Pumpkinhead.

Thanks for taking time to look at my project and hope you find it interesting and useful.

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