Ok, I’ve got a workaround.
- Whenever you query an attribute at a given time, query it at time - 1
first
Now the result is always correct, with or without IK, at the expense of one
more query.
*Example*
One quick way of achieving the effect is wrapping any call to getAttr with
this.
def getAttr(attr, time):
cmds.getAttr(attr, time=time - 1)
return cmds.getAttr(attr, time=time)
*Full working example*
from maya import cmds
# Build Scene# o o# \ /# \ /# o#
cmds.file(new=True, force=True)
a = cmds.joint(name="Root", position=(0, 0, 20))
b = cmds.joint(position=(0, 0, 0), relative=False)
c = cmds.joint(position=(0, 10, -20), relative=False)
handle, eff = cmds.ikHandle(
solver="ikRPsolver",
startJoint=a,
endEffector=c,
)
def getAttr(attr, time):
cmds.getAttr(attr, time=time - 1)
return cmds.getAttr(attr, time=time)
assert cmds.getAttr(a + ".rx") == 0.0assert cmds.getAttr(a + ".rx",
time=1) == 0.0
# Move handle
cmds.move(0, 15, -10, "|ikHandle1")
assert round(cmds.getAttr(a + ".rx"), 0) == -14.0assert
round(getAttr(a + ".rx", time=1), 0) == -14.0
# The above call also enables this other node to evaluate properly#
Which means we only need to call the special function once# per IK
node.assert round(cmds.getAttr(b + ".rx", time=1), 0) == 49.0
cmds.move(0, 15, -15, "|ikHandle1")
assert round(getAttr(a + ".rx", time=1), 0) == -4.0
This (luckily) works consistently across all current versions of Maya.
- https://github.com/mottosso/maya-test/pull/1/files
- https://travis-ci.org/mottosso/maya-test/builds/416763142
<https://travis-ci.org/mottosso/maya-test/builds/416763142?utm_source=github_status&utm_medium=notification>
It doesn’t quite jive with my understanding of IK and what Joe mentioned,
that it uses this internal callback. This workaround *shouldn’t* work, so
I’m a little weary still. Finally, I found that the Cycle Warning only
happens on Maya 2018, no other version; not even 2019. So I’m tempted to
just ignore it.
On Wed, 15 Aug 2018 at 07:43, Marcus Ottosson <konstrukt...@gmail.com>
wrote:
> Thanks Joe, that confirms my own research into this. I'm seeing traces of
> this all the way back in Maya 6.0, and not just related to IK, but
> time-related queries in general.
>
> - http://forums.cgsociety.org/archive/index.php?t-188420.html
> - https://forum.highend3d.com/t/non-correct-result-in-mdgcontext/38047/12
>
> Challenging, to say the least..
>
--
You received this message because you are subscribed to the Google Groups
"Python Programming for Autodesk Maya" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to python_inside_maya+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/python_inside_maya/CAFRtmOBt5p3jBZhFzfgVdJDnYfQ8N9fn019m8CtqL51pR_vYDQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
