3D Joint Tutorial in 13 Steps

Hello Everyone!

After creating my massive previous thread about the creation of my very first 3D doll, I wanted to do a proper tutorial focused specifically on how to create the joints themselves. There are a ton of resources on the net about how to use boolean functions and how to model humans/characters/etc. and even a bit about how to model action figures and their joints for 3D printing, but nothing specifically geared towards making BJDs. So I made this tutorial to help add some dolly resources ^^ You'll also be able to see my newest project whom I've called Yui. I have a few different heads in the works for this body, so this may not be her final, but I'll keep you guys posted.

I'll try to make this a WIP thread as well as a tutorial, but if it needs to be moved to somewhere else, let me know!

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Alrighty! On to the show!
Here's the body that I'm starting out with (awkward hands are awkward and will be fixed in blender later).
I modeled her in Sculptris and will export her as an OBJ file in Blender so those are the two programs we will be using. In the picture you can also see my rough guide in the back which I drew a few years ago. Keen observers will notice that this guide was used as a reference for a previous unfinished project of mine :3




Making the Joint Step 1.
Add a plane to your work space. You'll be using this like a knife to separate whatever parts you may be jointing. In my case it will be the shoulder joint.
Note: I am working in Ortho View which gives you a nice, non-distorted view of your model.




Step 2.
Place the plane you just made where you would like to separate your parts. Scale, rotate, and manipulate if needed to get a clean cut.




Step 3.
Duplicate the part you are separating making sure it is in the exact same spot as the original. In my case, I need to make a duplicate of the body.




Step 4.
Make sure your original part is selected, not the duplicate or the plane you made earlier. Once that is selected, open up the menu for the Boolean modifier by going to Tools > Add Modifier > Boolean.




Step 5.
In the boolean menu, select Intersection for the Operation and your plane as the Object. When done, click apply (if you don't apply after each modifier, everything will start to lag really badly).
Note: Notice that when the preview loads (if you have show preview selected) you should see that the body is now highlighted and the arm is not. This is because the modifier we are applying essentially "deletes" the un-highlighted part. In my case, it's the arm. If you want to know more about why this happens, see my previous post about Boolean Functions.




Step 6.
Repeat Steps 4. and 5. while selecting your duplicate part. This time set the Operation to Difference instead of Intersect. Now you can see why we made a duplicate of our original part.




Step 7.
You now have separate parts! ^^ If you would like, rename your newly separated parts to suit. You may also delete the plane you were using to cut with or move it off to the side to use later.




Step 8.
Time to make the joint itself!
Add as sphere, re-size it, and place it where you would like it to be for your new joint. In my case I squashed and rotated it a bit and stuck it at the top of my arm. Once that's done, select only the part you are adding the joint to (not your sphere) and apply a Boolean Modifier to that part. Select Union as the Operation and your sphere as the Object. This will join your part and your sphere.
Note: You can make your joints as precise and cleaned up as you would like. Mine does not look pretty at the moment because I'm quickly going through the steps of this tutorial, but once I'm done, I'll import my model back to Sculptris and smooth everything out.




Step. 9
Place your newly formed joint where you would like the socket for the joint to be. In my case, the socket I'm making is the shoulder socket on the body. After you place the part with the joint, select the part where the socket will be formed (again, the body for me). With that selected apply a Boolean Modifier with the Difference as the Operation and your joint part as the Object. In a traditional medium, this would be equivalent to squishing clay into a hole and then taking your ball joint and smooshing it around to form the socket.




Step 10.
The socket is all done! Next is the stringing channels.
Note: If you don't want to export and import your model to and from Sculpris and Blender, you can always clean up your model IRL after you've printed it out.




Really Quick Stringing Channels Step 1.
Add a cylinder or rectangle to your work space and flatten it. Use Difference in the Boolean Modifier to create the stringing channel that is found on the top of a joint. If you are unfamiliar with BJDs you can see in my awesome diagram of what I mean or just look up a few dollies with Google-sensei X3




Step 2.
Add another longer, more slender cylinder to the work space and use that to create a channel that runs through the full length of your part.




Step3.
It's kinda hard to see in the picture, but you're all done! You now know how to make doll joints in Blender, just repeat the process about a million more times and you'll have a completed doll X3
Note: If you would like to know more about what you need to do after jointing the doll, check out my previous post ^^





Thanks for reading everyone! Let me know if you have any questions

 

@tevaj
Thanks, I'm glad it was easy to understand ^^ I haven't done so yet, so unfortunately I wouldn't be much help. I know how to rig, it's just been sooooo long since I've done so, that I would need a refresher, plus I'm not sure on collision yet either.