Nicole continued to familiarize herself with Python in Maya. The Maya documentation on Python commands was very useful. She can now write basic python scripts that do things like drawing curves, creating objects, and getting/setting attributes of objects.
She did run into one problem. She was able to get joint position at a certain time with cmds.getAttr(‘joint_name.translate’, time = t). However, this returns the joint position in local coordinates, which never changes. (This makes sense, because bones can’t stretch.) Is there any way to get the position in global coordinates, aside from matrix multiplication, which would likely be too expensive to compute at every frame? Some commands have a 'global' parameter, but she's not sure how to add this to the getAttr call, since getAttr has no global parameter.
Once she figures out the world/local coordinate problem, she should be able to draw the translation curve along one joint, then extend it to the other joints.
Moving forward, any tips on how to compute the control points once we have the exact points along the curve?
Omar took time to try to figure out the best way to manipulate beta-splines in Maya. After working with the Maya C++ API, he found that MEL scripting may still be the better option. He made progress on the MEL UI, thanks to the help of the tutorials that he posted last week. Here's a screenshot of part of the UI:
Currently, a first window pops up, asking the user to specify the number of control points. This then brings up the Control Points window above, with the number of float field groups that the user previously specified. The user can input the x,y,z values for each control point. Hitting the Draw Spline button does exactly that. The above screenshot shows what it looks like after hitting Draw Spline. Also, if the user were to input new values into the window, it would just update the curve, not create a new one.
Next, Omar needs to add a way to manipulate the beta and/or alpha values of the curve (probably float sliders). Then, he would be about at the stage where he could use Nicole's control points. Right now, the control point input is interactive. Omar is still not sure exactly how the control points will need to be input/retrieved from Nicole's part, since Nicole is not exactly sure how to get them yet. They will figure that out together.
Question for Joe: For the beta review, what type of presentation do you want? Will we be talking over a video like the alpha reviews?
That's it.
Much lava,
Nelskati
Hi Nicole,
ReplyDeleteMaybe you could try the MEL command (or some other equivalent commands) "xform -query -worldSpace -translation;" to check the joint's translation in world scene.