[Robotics] Part 2 IK Armature Chains in GameEngine?
Florian Lier
blender at icram.de
Sat Jun 6 12:31:35 CEST 2009
Hey Benoit,
I created two blend files:
GE_IK_A.blend: is a simple IK chain where the IK solver is the head of the whole IK chain.
I inserted two KeyFrames as you'll see. When playing the animation only the head moves...
www.icram.de/GE_IK_A.blend
GE_IK_B.blend: the target IS NOT part of the Armature but the animation works this time
www.icram.de/GE_IK_B.blend
Adding a target for the IK solver which is also a part of the whole chain, let's assume the bone
after the IK solver bone doesn't work for me...
Maybe you can take a look and HOPEFULLY you can help me out. Would be great.
Thank you for your patience and your support.
cheers, Florian
---
MA
----- Original Message -----
From: benoit.bolsee at online.be
To: robotics at blender.org
Date: 05.06.2009 17:49:05
Subject: Re: [Robotics] Part 2 IK Armature Chains in GameEngine?
> If you post a blend somewhere, I can have a look.
> I repeat what I said before: in the GE the IK solver will only follow
> the target if it is a bone of the same armature.
>
> This is for 2 reasons: 1) the GE doesn't have its own IK solver, it uses
> Blender's 2) the constraint system that computes the IK target is
> ineffective in the GE: it is based on Blender's Object data (position,
> bones, etc.) that are not updated by the GE.
> Only actions are supported explicitely in the GE: while the GE is
> running an action, the Blender pose information is swapped to GE
> computed pose values to force Blender IK solver to use them. This
> swapping is effective only for the armature running the action. This is
> why the target must belong to the armature.
>
> Note that I'm working on a new IK solver for which some of these
> limitations will be lifted, if I have time.
>
> If you're not planning to use the game player, you should be able to get
> around these limitations by directly controlling the Blender objects
> inside the GE, using the Blender python API (versus the GE python API).
> The Blender objects are still present and fully accessible during the GE
> session.
>
> Benoit
>
> > -----Original Message-----
> > From: robotics-bounces at blender.org
> > [mailto:robotics-bounces at blender.org] On Behalf Of Florian Lier
> > Sent: vendredi 5 juin 2009 16:23
> > To: robotics at blender.org
> > Subject: [Robotics] Part 2 IK Armature Chains in GameEngine?
> >
> >
> > Hello Benoit,
> >
> > "> > > Yes, IK solver is fully supported in the game engine, at
> > > > least if you
> > > > > take a bone of the same armature as target. Add a floating
> > > > bone, make
> > > > > it the target of the IK chain, create Actions to control it
> > > > and play"
> >
> > Okay that's what I tried first, to avoid confusions I'll
> > describe my approach:
> >
> > Very simple:
> >
> > 1) I created 4 cubes
> > 2) Added 4 Armatures/Bones to the cubes (1 per cube) and
> > parented the bones to the cubes in PoseMode (Ctrl+P) - the
> > chain is calles "Armature"
> > 3) I added another "floating" bone to the 3D scene which is
> > not part of the chain mentioned before, let's call it "floater"
> > 4) Added a constraint to the last bone of the chain -> IK
> > Solver / ChainLen: 4 (orange line through all bones)
> > 5) I targeted (OB:floater) the IK Solver to the "floater"
> > bone (BO: Armature)
> > 6) By moving the floater bone in ObjectMode the IK Chain
> > follows perfectly
> >
> >
> > In ObjectMode
> >
> > A) Select the floater bone, press I
> > B) Go 50 frames forward move the floater bone (G) to another
> > position (Press I again)
> > C) Now I can replay the recorded action in the 3D window with
> > alt+a, the Action is called ObAction
> >
> >
> > In LogicPanel:
> >
> > D) Add a sensor (always), controller (AND), actor (Action)
> > E) Combine them and add an action Actuator (AC: ObAction)
> > F)Press P in 3D Window == NOTHING HAPPENS :/
> >
> >
> > 2nd Scenario
> >
> > "That's why you must go
> > > through an action that moves one target bone of the
> > armature itself."
> >
> > This is similar to the frist scenario, just without the
> > "floater" target, I'm moving the tip of the
> > IK chain, the rest is following, I can also record actions
> > similar to the first scenario.
> > The problem here is: I can play the action in GE but ONLY the
> > tip bone, which should be
> > the IK Solver moves, the rest of the chain doesn't move...
> >
> >
> > That's been a lot of text I hope I was precise enough. To
> > focus it: It's still a mystery to use
> > IK in GE - I'll do some research on using phyton this weekend -
> >
> > I appreciate EVERY consideration concerning IK and GE...
> >
> >
> > ---
> > MA
> >
> >
> > ----- Original Message -----
> > From: benoit.bolsee at online.be
> > To: robotics at blender.org
> > Date: 03.06.2009 17:40:08
> > Subject: Re: [Robotics] IK Armature Chains in GameEngine?
> >
> >
> > >
> > >
> > > > -----Original Message-----
> > > > From: robotics-bounces at blender.org
> > > > [mailto:robotics-bounces at blender.org] On Behalf Of Florian Lier
> > > > Sent: mercredi 3 juin 2009 14:00
> > > > To: robotics at blender.org
> > > > Subject: Re: [Robotics] IK Armature Chains in GameEngine?
> > > >
> > > >
> > > > Hey Benoit,
> > > >
> > > > First things first, thanks!
> > > >
> > > > Okay, as far as I understood you can "play" actions in the
> > > > GE... Maybe I wasn't precise enough: What I want is to
> > > > controll the IK chain "live" in the GE with a keyboard or
> > mouse....
> > > >
> > > > I have an empty object which is the target for the IK chain,
> > > > when I create
> > > > a Sensor, Controller, Actuator for moving the empty object in
> > > > the GE the chain/arm doesn't move at all...
> > > >
> > >
> > > That's correct: the IK solver uses the Blender's object position to
> > > solve the chain, but this position is not changed during
> > the GE session
> > > (GE converts blender object to GE object). That's why you must go
> > > through an action that moves one target bone of the armature itself.
> > > It's possible that you can change the bone position by Python but I
> > > don't know.
> > > You can do something a bit tricky: create 3 actions that
> > only drive one
> > > coordinate of the target bone: X, Y, Z. Make these actions strictly
> > > linear (1 frame = 1 meter + linear extension) and bind them to
> > > properties in the GE. Now you can control the bone in x,y,z by
> > > activating the 3 actions at the same time (same priority and no
> > > blending) and writing to the 3 properties the coordinates
> > you would like
> > > to put the target.
> > > I didn't test but I think it can work.
> > >
> > > > Is there any tuorial or howTo?
> > > >
> > > >
> > > > Cheers, Florian
> > > >
> > > > ---
> > > > MA
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: benoit.bolsee at online.be
> > > > To: robotics at blender.org
> > > > Date: 03.06.2009 12:13:45
> > > > Subject: Re: [Robotics] IK Armature Chains in GameEngine?
> > > >
> > > >
> > > > > Yes, IK solver is fully supported in the game engine, at
> > > > least if you
> > > > > take a bone of the same armature as target. Add a floating
> > > > bone, make
> > > > > it the target of the IK chain, create Actions to control it
> > > > and play
> > > > > the actions in the GE with the Action actuator: the IK
> > solver will
> > > > > compute the chain in real time in the GE.
> > > > >
> > > > > Benoit
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: robotics-bounces at blender.org
> > > > > > [mailto:robotics-bounces at blender.org] On Behalf Of
> > Florian Lier
> > > > > > Sent: mercredi 3 juin 2009 11:37
> > > > > > To: robotics at blender.org
> > > > > > Subject: [Robotics] IK Armature Chains in GameEngine?
> > > > > >
> > > > > >
> > > > > > Hello everybody,
> > > > > >
> > > > > > I've modelled a robot arm including an IK Solver which works
> > > > > > quite well. The next step would be, moving the robot arm with
> > > > > > some input device in the GameEngine - my questions is: Is it
> > > > > > possible to include the IK Chain in the GameEngine?
> > > > > >
> > > > > > cheers,
> > > > > >
> > > > > > Florian
> > > > > >
> > > > > > ---
> > > > > > MA
> > > > > >
> > > > > >
> > > > > >
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