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I have a snowman with a hat. Link here: https://www.dropbox.com/s/jji57qkhwe3yhhp/robotHat3_childOf.blend?dl=0

I want to animate the snow mans hand grabbing the hat and throwing it on the ground in front of him.

How would you go about animating the hat being released from the hand and falling to the ground. I need a simple and quick technique as I will be creating a variety of such motions.enter image description here Link to successful result; https://www.youtube.com/watch?v=kwYacsbW5Pg

Franck Louis
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2 Answers2

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Here I explain how to use Child Of constraint to make your character pick and hold his hat.

Also, give your hat Physics > Rigid Body > Type: Active. Give the ground Physics > Rigid Body > Type: Passive. At frame 0, enable the Rigid Body > Animated option of the hat and create a keyframe. The frame before he releases the hat, create a second keyframe. The moment he releases the hat deactivate Animated and create a third keyframe, the hat should fall.

moonboots
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  • Should the Child Of constraint be applied to the object being picked up or the hand? In your linked answer above you wrote that the target is the hand. I would have thought more logical to make the target the object? – Franck Louis Dec 03 '19 at 14:57
  • yes give the constraint to the object, and in the constraint there's a field called Target where you choose the hand – moonboots Dec 03 '19 at 14:58
  • Ok great this seems to do the job, Thanks. – Franck Louis Dec 03 '19 at 15:00
  • in theory it should work but I was too lazy to test so I hope I haven't missed anything in my explanation ;) – moonboots Dec 03 '19 at 15:08
  • Actually because my hat is parented to the snowman head, I am having some problem with the hat changing in size when I try to set the first influence value of 1 just before the hand throwing action of the hat begins. Any ideas what I might be missing? – Franck Louis Dec 03 '19 at 21:09
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    don't parent the hat to the head, use the Child Of to link the hat to the head bone? – moonboots Dec 04 '19 at 09:00
  • I still cant get this to work! Maybe its my version of 2.8 that's the problem. – Franck Louis Dec 04 '19 at 21:09
  • Please share your file (only keep the important parts) – moonboots Dec 04 '19 at 21:17
  • I think I may have found the problem; I removed the Visual RotLocScale and it seems to have done the trick. I will play around a bit more with the file to make sure there is no other problem and get back to you. – Franck Louis Dec 05 '19 at 09:51
  • Ok I have added link of Blend file in my original post. Still having problems with this. Can you help with getting the transforms to work correctly, Thanks. – Franck Louis Dec 05 '19 at 11:22
  • Why don't you use bones? It would make things much easier – moonboots Dec 05 '19 at 13:31
  • I just wanted to do it this way to see if I can get it working without using bones. – Franck Louis Dec 05 '19 at 14:40
  • plus you haven't applied the scales... :/ in my opinion that's not the good way, instead you should rig your character, it will make it much easier – moonboots Dec 05 '19 at 15:01
  • I'll try applying scale to see if it makes a difference. The problem starts when I set the first influence value to 1 and then press set inverse button; the inverse does scale back correctly. – Franck Louis Dec 05 '19 at 15:16
  • Yes not only you don't use bones but you haven't apply the scales, you should use the wise method for this kind of animation: Rig your object to an armature – moonboots Dec 05 '19 at 15:21
  • If you are curious, I have added a link to a successful result of the above in my original post. – Franck Louis Dec 05 '19 at 20:55
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Just solved it, after 3 days working on it! The cause of the problem ended up being something simple, as usual.

Just needed to unparent the hat from the body, which was the cause of the funny business caused by the "child of" constraint also being applied to the same hat.

Franck Louis
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    ok so that's what I actually told you: don't parent the hat to the head, use the Child Of to link the hat to the head bone ;) – moonboots Dec 06 '19 at 08:09
  • Exactly, so I gave your answer a tick. The problem is this whole process is very finicky, and sometimes doesn't seem to want to work even if it appears you have taken all the necessary steps, and in the correct order. – Franck Louis Dec 06 '19 at 09:48
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    Yes you can do a lot of things with Blender so you need to keep everything in mind so you don't mess up – moonboots Dec 06 '19 at 09:54