Monthly Archives: January 2012

Dem Bones

Toe bone connected to the foot bone. . . .

Thank you, James Weldon Johnson (1871-1938) for penning a catchy title I can borrow for my latest blog post!

Bones. Ah, yes. Currently the bane of my existence. I’m still working on Amanda’s book trailer for Syzygy, but it’s a slow go. With iClone and 3DS Max I’m not exactly starting from scratch–the concepts are all basically the same as Milkshape, but the processes are something else again. Thank God I got a decent understanding of bone assignments when meshing custom content for Stonehaven. If I hadn’t, there’s no way under God’s yellow sun I could grasp anything I need to do now.

Let me show you what I mean.

This is a shirt I made for Amanda’s character Tom, in his scenes before the Hawaiian shirt and pajamas:

I feel rather pleased with the meshing effort here, and although it took me nearly a week to learn my way around 3DS Max without relying on a step-by-step tutorial, I feel I could probably create similar pieces now in the space of a single afternoon.

However, there’s more to it. Muuuuch more.

With Sims 2, a handy-dandy little plug-in called Unimesh allowed the transfer of bone information between similar meshes, therefore I didn’t have to start from scratch every time I tweaked a mesh.

With iClone and its two-mesh-element system (which I will actually prefer, I think. . .once I get used to it) there is a nude torso element plus whatever clothing elements you add combined into one object called RL_Upper. This allows skin tone adjustments within the iClone engine as well as independent color and texture adjustments to the clothing. In other words, within iClone I can move a slider or two to change a red shirt to blue without making my character look like a Smurf.

But I discovered when I pulled a G5 character template into 3DS Max to make aesthetic adjustments to the mesh, I lost the bone assignments connecting the clothing mesh to the G5 skeleton. Below is a picture of what happened when I moved the arm bones to the classic “T” pose. The shirt sleeves should have moved with the bones, as demonstrated by the two nude torso pictures you’ll also see below.

See, here’s where it gets tricky for me. So in case anyone has wondered why it takes me so long to do ANYTHING lately, let me give you a peek into one itty bitty corner of my 3D world.

With Sims 2, there was a single skeleton. It looked like this:

Now, I’m working with an iClone skeleton that looks like this:

To further complicate matters, G5 characters have not one but TWO sets of bones, both of which are visible in the picture above. But both serve different purposes, and now I have to remember which bone to “skin” and which bone will wreck the entire skeleton if I skin it by mistake. Or I might have that backward. It might be which bones will wreck the skeleton if I animate them. Uggh.

Here are the two groupings:

At this point in the process, I’m still with the program. I’ve already committed the bone sets to memory and no longer have to refer to the skinning and rigging chart provided by Reallusion for iClone developers.

But the complications don’t end here. Now comes the tedious, detail-oriented part I wonder if I will ever master.

I managed to connect the shirt mesh to a G5 skeleton rig in 3DS Max. Yay! But here’s the result:

I’m sure you see the problem. The sleeves do indeed move with the arm bones, but there are some very disfiguring artifacts that distort the mesh and make it unusable in its current state. Believe it or not, this is not a mistake or even a disaster. This is simply the result of default bone assignments given automatically by 3DS Max. And this next picture demonstrates exactly what is happening to the mesh, and why.

If you look carefully, you’ll see that the artifact vertices are all red, as are most vertices in the trunk area of the shirt. Also, there is a smattering of blue vertices in the sleeves and trunk as well. 3DS Max assigns colors with the bone weights to visually demonstrate priority. Red vertices come under much greater influence of the individual bone than blue. Non-colored vertices are not influenced at all.

In the little rollout to the right of the shirt you might be able to see that the RL_Pelvis bone is selected. If the picture is too small in your browser and you can’t see that, just take my word for it. 😉 This means that every colored vertex you see is influenced by the pelvis. No wonder those pieces of shirt sleeve don’t move with the arm bones. They’re assigned to move with the pelvis, and at the absolute highest priority!

The last picture I’ll show you reflects my up-to-the-minute progress with this issue. Selecting those offending sleeve vertices and setting their pelvis bone weights to zero won me this small victory:

But as you can see, I now have to tackle those incorrect shoulder bone weights and, although I’m not uploading more screenshots to prove it, some extremely wonky weights in the abdomen area that create distortions when the skeleton bends forward at the waist.

*Sigh.* I’m not stumped. I know what to do. I just wish there were shortcuts. Yes, I can refine bone assigments on one side and mirror them on the other. That’s a huge time saver. But still. Even the tutorials say that this stage of the creation process is trial and error–that you just have to keep tweaking those bones until they affect the mesh the way you want.

Til next time,
Your bone-weary friend Rhonda.

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