Aligorith: since you seem to be active on the list again, can you spare some time to weigh in on this?
Thanks! --Nathan On Wed, Mar 7, 2012 at 11:39 AM, Nathan Vegdahl <[email protected]> wrote: > Poke poke, to Aligorith. Can you please weigh in on this? > > --Nathan > > > On Tue, Feb 28, 2012 at 11:04 PM, Nathan Vegdahl <[email protected]> wrote: >>> Hmm, I think we shouldn't change this without Joshua weighing in first, >> >> Agreed. He is the master of the animation system. :-) >> >>> but... it might be good to have an operator for it in the meantime? >> >> Good idea. This would be easy to whip up as a python operator. I can >> whip one up after I'm done with the rigging DVD, or if anyone else >> wants to whip it up it should be simple. Just something that loops >> over selections and normalizes quats on objects/bones set to >> quaternion rotation. >> >> --Nathan >> >> >> On Tue, Feb 28, 2012 at 2:18 PM, Bassam Kurdali <[email protected]> wrote: >>> Hmm, I think we shouldn't change this without Joshua weighing in first, >>> in case something dangerous will happen, but... it might be good to have >>> an operator for it in the meantime? so at least there's a way to >>> normalize/fix (I realize that that conflicts horribly with Nathan's goal >>> of not forcing animators to think about that stuff, something I agree >>> with completely, but just as a stop-gap) >>> >>> On Tue, 2012-02-28 at 13:16 -0800, Nathan Vegdahl wrote: >>>> Thanks Brecht! >>>> >>>> Yes, I think there are problems with this approach too, and I can see >>>> why it would cause confusion. But I think it's better to have this >>>> for now until we figure out something better. >>>> >>>> One possibility would be to only have normalization happen when >>>> inserting keys. It's only a problem when things are animated, after >>>> all. That could also be confusing, though, since people will wonder >>>> why the values change when they insert keyframes. >>>> >>>> Or perhaps we could have auto-normalization happen on frame changes? >>>> >>>> In any case, I think it's important that--however we set it >>>> up--animators should not need to understand all of this to animate >>>> with quaternions. >>>> >>>> --Nathan >>>> >>>> >>>> On Tue, Feb 28, 2012 at 12:26 PM, Brecht Van Lommel >>>> <[email protected]> wrote: >>>> > Hi, >>>> > >>>> > Ok, I found the commits that removed this auto-normalization. First it >>>> > was changed for pose bones in r27200, and then for objects in r33523 >>>> > to make it consistent. For pose bones it was changed by Joshua with >>>> > the comment "This was a constant source of confusion in the past, so >>>> > let's see if we can do without it now :)". >>>> > >>>> > I can definitely see the interpolation issue when they are not >>>> > normalized. So the question then is, what was this confusion? >>>> > >>>> > One issue perhaps is when you want to enter a particular value for the >>>> > quaternion, if it keeps normalizing each time you enter a value, that >>>> > would be a problem. >>>> > >>>> > Another issue with the implementation that I can see is that the >>>> > normalization was done in object update, so not on editing only but >>>> > also on any object animation evaluation. If you then animate only one >>>> > of the quaternion components, the other values keep changing as you >>>> > scrub through time and actually alter the animation. So perhaps that >>>> > should be done differently, though it's not something you would do >>>> > often I guess. Doing it immediately in RNA would also be problematic >>>> > if you're setting the quaternion component by component in a script, >>>> > the normalization does need to be delayed somehow. >>>> > >>>> > Further, probably Joshua knows, mailing this to him as well to get his >>>> > opinion.. >>>> > >>>> > Brecht. >>>> > >>>> > On Fri, Feb 24, 2012 at 9:37 PM, Nathan Vegdahl <[email protected]> >>>> > wrote: >>>> >> Hi Brecht, >>>> >> You are right that it appears there are a lot of releases with this >>>> >> regression! I'm not sure how I didn't notice before. Guess I wasn't >>>> >> animating anything with large rotations. >>>> >> >>>> >> It appears the regression was introduced in version 2.56. Versions >>>> >> 2.55 and earlier behave as desired. >>>> >> >>>> >> 2.4x and earlier _do_ auto-normalize (I just tested). In the 2.4x >>>> >> series quats are displayed as eulers in the n-panel, so you have to >>>> >> set keyframes and look at the values of the keys in the Ipo editor to >>>> >> see the actual quat values. Try, for example, keying a bone unrotated >>>> >> on frame 1, then rotated 180 degrees on frame 21. On frame eleven >>>> >> it's clear that the values given by the Ipo curves are not normalized. >>>> >> However, if you move to frame 11 and set a key, the inserted keys are >>>> >> normalized. >>>> >> >>>> >> This is a highly desirable behavior, because it keeps quaternion >>>> >> values from drifting and causing rotation speed issues with >>>> >> interpolation. >>>> >> >>>> >> Perhaps we could just normalize quaternion values upon inserting >>>> >> keyframes? That is the primary use-case here. >>>> >> >>>> >> --Nathan >>>> >> >>>> >> >>>> >> On Fri, Feb 24, 2012 at 7:51 AM, Brecht Van Lommel >>>> >> <[email protected]> wrote: >>>> >>> Hi Nathan, >>>> >>> >>>> >>> I tried manually typing in non-normalized values in the N key >>>> >>> transform panel in the 3d view, and rotating objects/bones after that >>>> >>> with transform, but could not see it auto-normalize the values in any >>>> >>> version I tested (2.49, 2.57, 2.60, 2.62). >>>> >>> >>>> >>> Probably I'm misunderstanding something, but I can't find any traces >>>> >>> of this feature. >>>> >>> >>>> >>> Brecht. >>>> >>> >>>> >>> On Thu, Feb 23, 2012 at 11:03 PM, Nathan Vegdahl <[email protected]> >>>> >>> wrote: >>>> >>>> Hi guys, I wrote to the list about this before but received no >>>> >>>> response. >>>> >>>> >>>> >>>> I don't know when this was changed, but quaternion rotations for >>>> >>>> objects and bones in Blender are no longer auto-normalized for the >>>> >>>> user. I am frustrated that a release (2.62) made it out the door with >>>> >>>> this being the case, as it substantially harms the practicality of >>>> >>>> animating with quaternions. It is not "incorrect" behavior per se, so >>>> >>>> I am hesitant to file a bug report. But it is something that needs to >>>> >>>> be changed. >>>> >>>> >>>> >>>> I think we either need to revert behavior back to how it was before >>>> >>>> (quaternions being auto-normalized in the transform panel), or find >>>> >>>> another solution. But as things are right now, quaternions are >>>> >>>> impractical to animate with in many circumstances (especially doing >>>> >>>> blocking on characters involving large rotations). I will be happy to >>>> >>>> provide a technical explanation of why that is the case, but at the >>>> >>>> moment I am swamped trying to finish my rigging DVD. >>>> >>>> >>>> >>>> I just want to make sure this doesn't slip into the next release as >>>> >>>> well! It is a serious regression. >>>> >>>> >>>> >>>> --Nathan >>>> >>>> _______________________________________________ >>>> >>>> Bf-committers mailing list >>>> >>>> [email protected] >>>> >>>> http://lists.blender.org/mailman/listinfo/bf-committers >>>> >>> _______________________________________________ >>>> >>> Bf-committers mailing list >>>> >>> [email protected] >>>> >>> http://lists.blender.org/mailman/listinfo/bf-committers >>>> >> _______________________________________________ >>>> >> Bf-committers mailing list >>>> >> [email protected] >>>> >> http://lists.blender.org/mailman/listinfo/bf-committers >>>> > _______________________________________________ >>>> > Bf-committers mailing list >>>> > [email protected] >>>> > http://lists.blender.org/mailman/listinfo/bf-committers >>>> _______________________________________________ >>>> Bf-committers mailing list >>>> [email protected] >>>> http://lists.blender.org/mailman/listinfo/bf-committers >>> >>> >>> _______________________________________________ >>> Bf-committers mailing list >>> [email protected] >>> http://lists.blender.org/mailman/listinfo/bf-committers _______________________________________________ Bf-committers mailing list [email protected] http://lists.blender.org/mailman/listinfo/bf-committers
