Adding Unity Tools

Waiting on videos to render is the perfect time to add and update site content, because everything else is bogged down. In that respect, I wanted to note that my Unity tools page is now open for business, where I will be posting more components and editor scripts in the future. For starters, I have uploaded two basic components (each zip file contains a UnityScript and a C# version).

The first component is an aim constraint, to simply mimic the behavior of Maya’s aim constraint. The benefit of using this over a simple call to Quaternion.LookRotation() is that you can specify arbitrary forward and up axes on the constrained object (just as in Maya). You could use this with the AssetPostprocessor class to automatically import constraints in your asset files (FBX, Maya, etc.).

The second component is a look rotation constraint. It allows you to not only specify arbitrary forward and up axes on the constrained object, but also constrain it to a world forward-vector and world up-vector (so it does not need to aim at a target, but can mimic the “pointing” direction of another transform).

Hip Constraint and Shoulder Constraint Update

Following in my pattern of frequent updates, I uploaded more revisions this morning to both the shoulder constraint and hip constraint.

The revision, which is the same in both, is another exception to handle a possible singularity. I never actually had it happen to me in practice, but I realized it was possible when I stopped to think about it. Enjoy!

Hip Constraint Release and Shoulder Constraint Update

This morning I finally finished the hip constraint! You can now download it here. Just like the shoulder constraint, it comes with MEL scripts designed to assist in setup.

Speaking of the shoulder constraint, I found some pretty egregious math errors in my shoulder constraint node, so I have uploaded another update to it. Not only does it actually work as intended now, the math is greatly simplified and more closely resembles what you need to do to port it into game code.

Enjoy, and please let me know if you have any problems while using it!

AM_ShoulderConstraint Update

I have been working the past couple evenings on another Maya plugin, a hip constraint. It is finished, but the setup tools are not yet ready for it, so expect it probably by this weekend! While working on, however, I discovered a couple bugs in my shoulder constraint node, so I have uploaded an updated version of that (1.1). The update is not a big deal and the chances of it affecting anyone are very slim, but I did primarily two things.

First, I now cast the incoming enum for rotateOrder as short instead of as int, as there is a known problem in Maya Python accepting pointers to integer as reference to enums. For whatever reason it did not appear to cause a problem in my plugin, but I would rather be safe than sorry.

Second, I slightly adjusted the math for building the final quaternion. Though I never actually saw a problem with it, there was the possibility of building a weird rotation if the shoulder’s pretransformed up vector was exactly 180 degrees from the world-space target up vector (i.e. there are infinite different possible quaternions to build the rotation from one to the other). The problem can still happen only if the pretransformed up vector is exactly 180 degrees from the world-space target up vector and the shoulder’s transformed (world-space) up vector is exactly 180 degrees from the target up vector. Because the chances of this happening in a human range of motion are infinitely small, and the chances of this configuration of vectors is infinitely small, I didn’t bother to devise a more elegant solution. However, please do let me know if any of you have a different suggestion of how to address it!