Introduction: Create a Unique Burial Urn
Hello! My name is Andy de Bruin, I do 3D design and printing as a hobby. I like to find creative solutions for things that are challenging to me. In this particular case, a familymember passed away and I was asked if it was possible to re-create a model of a certain statue in the city of Harlingen (Netherlands) called "De Stenen Man" or translated as "The Stone Man".
A little more background on this project as I find it is important to show what you can accomplish with 3D printing and a bit of design. This certain familymember has always lived it's life in the city of Harlingen and was a proud citizen of this city. His family thought it would be a nice and final tribute to him and his life to have a bit of his ashes contained in a custom-made burial urn. Various sculpters, designers and artists were contacted, but all of them had really high prices or no time. They asked me too but I didn't have the time back then and I just had sold my 3D printer so printing it myself wouldn't be possible. Having a burial urn sculpted or modelled by a artist in clay or even 3D, would apparently cost heaps of money. Months later I was contacted again for advise and I decided to give it a go! The printing would be solved differently.
So here's my take on how to create a personal burial urn for those loved ones. You do have to have some experience with 3D modelling but it all depends on what you want to create ofcourse! It can be simple or you can go complex, that's the beauty of design and 3D Printing: it doesn't matter! If you can make it, you can print it!
Step 1: Planning Ahead and Design
Gather as much reference pictures as you can of the thing you want to model. Without reference you will always miss something in the process. It's probably boring but has to be done in order to create something decent. In this case I was going to model a statue. There were not a lot of good pictures to be found. Preferably it would be nice to have front- and side-reference photo's or even better, a small miniature sculpt or something like that. I had that luck and the family send me a load of photo's and even a small miniature of the statue. They even measured it's height and width of the thing for me as well as the height of each segment! So, gather all the data you can get, it will speed up the process.
This statue has a lot of small details and even what looks like a sort of series of small drawings on it's sides. So here are the considerations I made:
- I came up with the idea of dividing the statue into 2 separate parts so it can function as a container. I would first model the whole thing as accurate as possible, meaning it's size and also the sizes of each segment, so everything would be proportional and sound.
- After that I would split the object in 2 parts and make some cavities and high walls or edges, so I can fit the top-part into the base (which will contain the ashes). Also this needs to be done so the top part wouldn't fall over because of it's size. It would have to fit perfectly.
- I need to make it hollow. Both parts. This is to save on material, weight and money. I didn't know where it was going to be printed so I had to keep in mind that when making it hollow, it had to have a nice thickness to it's walls.
- I need to find a way to have this printed in a very cheap way. The family wanted a small version, 20 cm's in height (between 7 and 8 inches).
For this project I will model the details in Zbrush. I made a basemesh in Modo because I find it a bit easier to create a fast and size-accurate model in this program. Ofcourse you can use whatever 3D package that's out there but for this job I found Zbrush a fast way to create something. The photo's you will see are from Zbrush. I can't go in depth and lengths with how to model in Zbrush, that's a whole other project and there are certainly better people out there who have decent tutorials on that ;-) I give my own view and tips on how I made this, I hope you understand.
In Modo I made a mockup of 20cm in height, just a box actually. I then (almost like tracing) divide it up in the sections you can see on the statue, and I make sure it's all symmetrical. So now I have a decent base to work from. I export this to Zbrush to continue the design process. Zbrush is very much like sculpting something with clay. A Wacom-tablet is very handy for this purpose but it can also be done with a regular mouse though, but working with a tablet is more intuitive and sensitive in my opinion.
Once in Zbrush, I divide the model up to a few million polygons. Zbrush is excellent in handling millions of polygons with ease and I need that much to get the detail in (icons, drawings etc). If you don't you'll get jagged edges and it will look terrible. Don't worry, when we're done with modelling we will bring it's polygon-count down.
To get the small details onto the object you can go multiple ways; you can either model/sculpt them by hand or for instance, mask the details, invert them and extrude them outwards. It's a easy and fast process to get things quickly done. With most of the icons on the top part of the statue, I traced them over from a photo in a graphicseditor and filled those tracings with white. I make a black background an now I have a so-called "Alpha" or stencil that I can use in Zbrush. The white color is high and black is low. This way you can draw accurate shapes and extrude them or do other things with it.
Step 3: Splitting the Model
Next I will need to split the whole object in 2 parts. This easy to do in Zbrush. There are more ways to do this but I just use the "Slice Curve"-brush. Using this brush, draw a cutline were you want the object to divide. I already have the model in "Dynamesh" -mode (Can be found under the Geometry tab). After using the slice-curve brush, you will have 2 different polygroups. Re-dynamesh the model again and you will have to different objects. Split those objects into separate subtools (subtools can be thought of like layers in Photoshop). You can split them using the Split Objects function under the Sub-Tools palette/tab. Now you have to 2 separate objects to work with.
Step 4: Creating Cavities and Support
I want the top-part of the statue to "sink" a bit into the basemesh. Think of it like a key in a hole. I will fit firmly and won't topple over. It's in essence a add and subtract process, nothing more. First I will determine how deep this cavity will be, I don't need it to be all the way to the bottom of the base because I will make it hollow afterwards and it will have to contain some ashes. So I decided to just let it sink in a little bit. In order to have the right size and depth, I also need to create a cube or block that wil extend from the top part. I will be smaller then the bottom of the top part, I just need it to function as a key.
You can easily add a cube with a insert-mesh brush (cube) or add a cube as a subtool and merge it to the existing top part object. If you Dynamesh it again, it will merge and become a solid object. The screenshots will show you what to do. Make a copy of this top-part as different subtool. You will need to subtract this top part with the base and then you will have the desired cavity with it's depth. In this process the subtool that you use to subtract will disappear so that's why you need to make copies if you do this ;-)
Step 5: Making It Hollow
Finally, when I'm happy with the overall look of the statue I need to make it all hollow so it will save on printing costs, material and also on the weight. It's a fairly easy process in Zbrush, you sometimes need to experiment with a certain thickness of the walls and support. It's actually a one-click process, Zbrush does all the calculations.
The way it work is explained in the photo's but here's a fast version. You need to make sure the objects are in Dynamesh-mode. Use a Insert-Brush, cube, to show Zbrush were you want the entry hole to be. You don't need it to extend it or push it all the way through the model or object, just have it protrude a bit into the mesh. The size will determine the entry hole.
When creating the Insert-Brush onto the object, hold down the ALT-key. This wil invert it and be an subtraction-object from then on. When you go to the Dynamesh-palette/tab, you will find a button named "Create Shell". Give it a certain thickness and click the button. You might get a window saying you need to clear the mask first. This is because when you using Insert Mesh Brushes it wil mask everything off except the brush you are inserting. Just CTRL+click/drag and release next to the model and it should be cleared!
Making it hollow can take some time depending on the size of the model (polygon count that is) but if everything's well, you will see a nice entry hole and the whole thing is hollow. You might need to do it again if the walls are to thin so keep that in mind.
Step 6: Prepare to Print
Bringing down the polygon count
After the whole model is finished and approved, you will need to bring the number of polygon's down to a reasonable size. Currently is consists of roughly 1.5 to 2 million polygons. 3D Printing software can't handle that amount well for now and actually for this model it isn't much needed. Zbrush has a plugin called Decimation Master. It will recaculate the amount of polygon's needed to still hold all the detail. Works really well and I brought it down to roughly 500.000. You'll probably say that's still way too much but since I'm not sure on what type of printer this will be printed, I want all the detail I can get! 500.000 shouldn't be a problem either, it's proved and tried by me many times before even with the printer I had back then.
Checking and prepping for printing
After that, I export the .STL to Netfabb and do quick check to see what thickness the walls have. Too thin, it will probably come out warped or messed up and to thick, it will have more printing time and more costs. Netfabb has a quick way of checking thickness. So you might repeat some certain steps to have the correct thickness desired for printing. There are certain materials out there and printers that will have problems with very thin layers or walls, especially if you want your model to be casted in a precious metal. You will have to find a bit of balance in that and do the making it hollow part again. Be sure to safe regularly! When all this is done it can be printed! Yes!
Since I didn't own a printer myself anymore I had to find a way so the family could do this part for theirself. What easier way to have someone or a company to print this is and send it out. They wouldn't need my involvement. So I gave them a bit of advise of what kind of material that was needed (they also wanted to paint it!) and what to look for. This statue could be printed on a reasonable home/desktop printer or on a industrial kind of printer.
Another reason I made the object in 2 parts is that you wouldn't need a printer with a printing buildvolume of 20 cm's, so more options on that end! In the end it was almost 3 times cheaper doing it this way and print it in ABS plastic through a Hub @3DHubs than go to one of the big companies that are out there. So there's a testimony for ya ;-)
Everyone was happy how this turned out and the family had 2 copies made, painted it in silver theirself and were very happy to have something unique close to them. Hope you find this useful! Keep on printing!