November 18, 2012 at 2:48 am
I am going to start making an effort to document my process. I’d love to make videos.. but I can’t do that until I get a new computer since I have less than 1GB of free space. So, for my first process walk-through, I am going to show how I joint my faces, since it is one of the few parts I have done multiple times. I’m not going to show how I model the face itself right now (since it was done a while ago and tutorials like that are fairly common). I am going to joint my zombie character face.
Some things you should know before I start:
I do almost all of the jointing with booleans. A boolean is an operation using two or more objects. The main functions I use are subtraction, cutting part of a object where a second object overlaps it, and intersection, taking the overlapping part of two objects. Booleans can be a pain – if there are holes in your mesh or other weird things going on that you may not even see, it could bug and not work. Sometimes it won’t work and you won’t be able to figure out why. If it doesn’t work, the best thing to do it first select all open edges to make sure none exist where they shouldn’t. If that doesn’t help, then it may be more complicated. Also, it will by default remove redundant edges. There is a select box at the bottom to only remove invisible edges that I normally choose so I don’t mess of the flow of my meshes.
I work in high polygon – I generally turobosmooth it until I can just make out all the polygons at a reasonably close zoom level. This can make things much more of a pain, but I find it essential. If you cut into a lower polygon mesh and smooth it after, the parts might not flow smoothly. It is also likely that a boolean will result in jagged edges with low polygon models.
A lot of what I am showing you involves things I made a long time ago that I do not have screen-shots of. Since I am making all the faces fit the same headcap, I reuse parts. I also have to do some funny things because sometimes my new faces won’t line up perfectly to my old face parts. I’ve probably changed something at some point without realizing that it changed the way parts of the model line up – it isn’t a big deal but causes me a tiny bit more work.
Since this is all stuff I’ve done with a lot of trial and error, the flow of the guide isn’t exactly the way I originally did this. You will probably need to throw a step or two in to do what you need to do. You may also have to redo some steps a few times if they aren’t working out. Make sure to save a new copy at every major change – it can save you a lot of work (there is a reason my hard-drive is full).
This is assuming you know a bit about 3D modeling, but feel free to ask me questions. Everything is done in 3ds Max – I am not sure how this would translate to other programs.
As a tip, I recommend using a sky blue background. For me, it actually makes a huge difference. It is much more natural than grey and just “feels” better to work with.
Step One – The Neck
So we have our model – I’ve cut off everything below her neck to make it easier to work with. The first thing we want to do is to transform the bottom of her head to fit the neck. Now for the face itself, most of this is will just get cut off. In theory you will be making the back of the head at the same time. I already have that, so to keep this from getting too long, I am just going to focus on the face. The back of the head is done with similar techniques.
Slice The Neck
The first thing I do is make a plane that will help me make the proper slice at her neck. This is something I did a while ago, but I basically just made a plane say, 4 by 4 polygons, and turbosmoothed it few times. Then I manipulated the plane, which was easy since it was low polygon, until I got something that looked like a good shape for the neck slice. The picture here is with a new plane that I made using the edge of an already cut head (it keeps things cleaner). Where it intersects the neck is essentially the same. I selected the outer edge and pulled it down because I find it helps with the boolean.
Once I have my plane where I want it (in this case I just reuse the same plane for all my faces so I don’t change anything), I use ProBoolean to make the cut. First select the face, then create the boolean. ProBoolean is under Create > Geometry > Compound Objects. In the ProBoolean menu on the side, you will want to check Subtraction (should be default). I also recommend going under Advanced Options and under Planer Edge Removal, selecting Remove Only Invisible, so you don’t loose any edge loops. Then click Start Picking (the button on the top), and select your cutting plane. It should cut off everything below the plane. If all went well, convert back to an Editable Poly (if not, you are going to have to try to figure out what broke it). You may have the faces that made up the cutting plan attached to the part you just cut. If so, just delete those new faces. They should be selected automatically. If not, they probably have a different smoothing group so you can try selecting by that. You’ll have a bunch of vertices along the border that aren’t part to the edge loops of the head. I highly recommend using Vertex Killer
to remove all the extra vertices. The script works by removing the ones that are only attached to 2 edges – it is extremely usefully when working in high polygons (I used to manually delete all the extra ones, it took forever).
Her face is a bit smaller than Oriana’s whose I based the cutting on originally. It would be better to have the cut closer to the jaw, so that there is just a little space between the jaw line and the cut. I have to keep it consistent for now so this will have to do. I can make it better later once everything is all together.
Create the Inner Joint
Now we want to actually make the inner part that is going to rest on the neck. Obviously, this should be in the shape of the neck, which is generally a sphere. This is another thing I have already done and is a bit more complicated – now I just reuse the inner part by attaching it to the head, but I will show how to do it.
So I have a sphere that I also used to make the top of the neck. I want to somehow connect this to the head as we have it. Now, I could have just used this to cut, but then the faces of the head would not flow nicely with the faces of the sphere, which would make it hard to smooth. So, I want to select the open edge of the neck, and copy the edges by holding down shift, and scaling down.
I am going to detach these new faces to make things easier to work with. Just select the open edge loop, right click and click “convert to face” and detach. Now we want to keep copying edges of this to surround the sphere. Just keep selecting each new edge, and scaling/moving it (don’t move it side to side, just up and back/forward) to surround the sphere – it doesn’t have to be perfect, just make sure everything is outside the sphere. Don’t change the edge that matches the edge on the neck
– we will be reattaching it so it needs to stay exactly the same. The pictures are kind of misleading – the bottom border in the picture on the left is the border we took from the face. I took the first copied border from the picture above and re-scaled it out, so the highlighted border in that picture is the second edge loop from the bottom on the left picture. The more layers, the smoother it will be. I am not going to bother with many for this example. I cap the top, and flip the normals.
Now we want to conform this thing we made to our sphere. Select the top face, and select down to everything except the last two faces. Then, convert the selection to vertices, so that everything but the bottom two loops is selected. Now we can conform it. Conform is in the same menu as ProBoolean. With the piece selected, click Conform, and gown down the options and choose “Towards Wrapper Center,” make the Projection and Standoff 0, and choose Use Selected Vertices (so the bottom doesn’t change). Now, click Pick Wrap-To Object and choose your sphere. If it looks funny, mess with Vertex Project options. My model is not that great – I should have copied more edges so we had more of the top of the sphere, but I didn’t bother for this example. You are probably going to have to mess with it and try a few time to get it better. The sphere probably does not need to be complete up top since you are most likely going to be making a hole for the elastic to fit, so a flat plane will do until it is later cut. Just make sure it small enough so that the hole you eventually cut will cut off the part that doesn’t cover the sphere.
Delete the spheres so you are left with just that piece we conformed (you probably want to keep the main sphere and hide it for future reference – it is useful if you want to know the exact pivot point). We want to fix it so the part that connects to the neck flows smoothly into sphere part. Luckily, there is a function called Relax that won’t mess up the border. So, select the Border, and go to Smooth Selection. We want our Smooth Selection to cover the part that juts out, plus a bit more. For me that is an Edge Distance of 2 and a Falloff of 10mm. With that selected, go to your modifier list and choose Relax. Make your Relax Value 1, and keep upping the Iterations until it is smooth – for me it is at around 80. Make sure Keep Boundary Pts Fixed is selected! You might have to mess with the Smooth Selection parameters. Once you have it how you like it, collapse the modifier.
Now we can reattach this to the head! Just select the object and flip back the normals. Unhide your head, and select it. Attach the neck piece to the head, and select the open vertices (or all of them, but I prefer just the open ones). This is under the Selection menu up top, or you could select the borders and convert it to vertices. Then, in the Edit Vertices menu, click the button right next to the Weld button. I change the value to .005 or something small to make sure nothing gets welded that shouldn’t be. Weld it, and then select open vertices to make sure everything was welded (it should be – we didn’t change that border). Now we have a head that will fit on a neck joint!
Smoothing the Neck Edge
Since we made the inner neck part by copying the border, it will smooth pretty nicely. I changed the inner neck part to the part that is consistent with my other heads, which is why it is different than the pictures above. I also have a bunch of numbers written down with pictures of edges to select so I remember what to do to make sure everything is consistent. What we want to do here is round out that hard edge. Select the hard edge for the neck – this is pretty easy by choosing Select Hard Edge on the menu at top, while you have edges selected, and removing all of the edges that aren’t part of what you want. I make sure I don’t have anything extra selected by just dragging the vertices out seeing if something moves that I wasn’t planning. Choose soft selection and adjust it how you see fit. Then relax it as before, and keep adjusting the relax values and soft selection until it is how you want it. When it is good, collapse the modifier.You might be done after one relax, but you’ll probably have to do a few more to get it looking right. I had to relax the front of her neck a few times to smooth out that lip, and then fix a couple bumps that created. It is okay if it isn’t absolutely perfect. You have going to have to do some post-printing-work anyway, but obviously the less you have to do the better. Sometimes it is more worth it just to plan on sanding down some areas, but you should try to get it as close as possible.
Next we will separate the face from the head. Here is Part 2.